Heat and Corrosion Resistant Alloys
Episode 3
June 6, 2020
Rob Hamm:
We are excited for you to join us today on this latest get sparked episode. I’m your host, Rob Hamm, along with Pete Koegel and Allen Stoltzfus from R-V Industries today. Pete and Alan will be talking with Marc Glasser, a metallurgist from Rolled Alloys. Rolled Alloys is a supplier in the metal industry for both heat-resistant and corrosion-resistant alloys.
Rob Hamm:
Good morning, Mark. I was wondering if you could share with us today a little bit about your journey of becoming a metallurgist.
Marc Glasser:
Thank you, Rob. I started out 40 something years ago when I was in college at RPI in Troy, New York. I started out as a science major and I quickly realized that my particular interests were more in patients rather than pure science, which meant engineering. And I wasn’t sure exactly which way I wanted to proceed, but because of another activity that I was involved in, which was managing or division one hockey team, I had the opportunity to get to know a lot of people in the school’s administration, particularly in the engineering groups. And I got to talk with them quite a bit and they helped me to realize that my particular interests were pointing me straight in the directions of the materials engineering department. So I changed my major and the rest was history.
Pete Koegel:
That’s interesting. How much have things changed just in the science and the alloying technology seems to do a double every decade. What would you say is the biggest difference since you came into this field and the things that you’re operating and working on today, Mark?
Marc Glasser:
Well, I think the biggest difference is actually in the personnel area because when I was in school material, science was basically metallurgy and it’s evolved to the point where there are so many areas now of material science, that there aren’t as many metallurgists. And I think as a country, we need, we need to bring back metallurgy curriculum to the schools so that we can restaff in the next couple of decades.
Allen Stoltzfus:
What are some of the other focuses within the material science field now that it’s changed outside of just metallurgy?
Marc Glasser:
Well, it started back in the late eighties and I think it was facilitated because of the weakness in the steel industry in the eighties, because in the late eighties, early nineties, you saw a lot of bankruptcies. And the reason that people went into metallurgy was because there were jobs and that started changing the next place that started really hiring materials people was the semiconductor industry. I actually started on a master’s degree at night in 1989. I finished it up in 1994. The emphasis was on semiconductor materials.
Pete Koegel:
That’s where the industry was headed at that point?
Marc Glasser:
That’s the industry that I was working in. It was the metals aspect of semiconductors. Sputtering targets that we used to put on the layers on the chips. But as that evolved, it moved on to nanomaterials, which is where there’s a lot of focus now, thin films, which are used in the areas of solar power. And they’re back to composite again. A lot of emphasis on plastics. But what you’re seeing now is with the baby boomers retiring there’s, I believe there’s going to be quite a need for people in the metals producing industry and the heat treating industries and in the fabrication industry. So I think there’s opportunities for those who see it and are willing to seek it out.
Pete Koegel:
Yeah. Agreed. And something I’ve always thought about more from a future perspective, everything you see in space, even call it next generation stuff. There’s obviously ceramics and composites involved, but structure, it’s all, aluminum and titanium and alloying, at least from my view, metals and metallurgy is not going away. Fabrication of those metals is not going away anytime soon. That’s at least in my perspective.
Marc Glasser:
And I would tend to agree with that with the proviso that there are a lot of people trying to figure out how to use additive manufacturing as a supplement. The basics of what we do of fabrication. That’s not going to change because when you’re dealing with big parts where you’re bending them and forming them and shaping them and welding them. Still, the fastest, the most productive way to make things is still by having plate and sheet and making it as opposed to an additive manufactured part where it might take you a day or a week or a couple of weeks to print the part like that.
Pete Koegel:
Alan was actually just working on a small little additive project with one of our design engineers, working on getting some costing and some different material types, including plastic. But yeah, it’s it’s becoming more popular, but the size and the scale of the stuff that we’re typically building and the applications that you’re supporting with, metallurgical review, be it high temperature, high oxidation, isn’t typically a good candidate for additive. And it would be the conventional subtractive manufacturing, I guess, is the, is the opposite term there? What kind of specialty do you work in now within Rolled Aalloys? You know, what is your day to day look like?
Marc Glasser:
We have two classes of alloys corrosion-resistant alloys and heat resistance. My particular area of expertise is the heat resistant area. Okay. So I try to feel the questions in that area of the business. And one other person on my staff is more expert in the corrosion-resistant area. And I try to fan those questions out to him, but because of the way we’re set up, we try to do enough work in question-answering in each other’s areas so that we can keep up and learn from each other. We’re going to be adding some new ideas to our routine so we can cross-pollinate and learn from each other going forward as we bring the next generation of people into the business. From a day-to-day perspective, I think there are several areas that I get involved in. The first one is proactive, technical marketing, where I’m going out and I’m finding people who are using our materials and there may be better ways for them to use the materials or maybe better ways for them to use. And I’m trying to find the people who have been good to us and work with them, get them into even more good things so that they can improve their business and grow their business. The second area would be what I call reactive technical marketing. And that’s where people call in and ask questions. They send in email questions. We try to answer those within, within a day.
Pete Koegel:
Got it. So if I’m a mechanical engineer and I’ve got something that I’m walking out to my plant and it’s just rotten away and it’s in a high heat application and we’ve got another one spare that we’re going to throw in, but we’ve got to figure out a new solution, and we’re currently not using any Rolled Alloys products. I send in the design conditions. Can you help me out? You’re the guy giving me a call to find out exactly what the application is and stresses and temperatures.
Marc Glasser:
Correct. We may play 20 questions, but I’m going to ask you all these questions so I can zero in on the right options for you. To support this kind of work. Some of the other things that we offer as a company that makes us very unique, we have a metallurgy lab where we can do metallurgical investigations, which can cut materials apart see what’s really going on and help guide you to the right solution. We have a sample inventory. So if, as you say, your parts are not lasting, as long as you expect them to, and you put in a spare at your customers, but it’s the same thing. You know, it’s not going to last as long as they expect it to, or you at least have a reasonable expectation that it may not last as long, we can sit and talk and figure out what the candidate alloys would be. And then we can send you samples of three different alloys that you can insert in your atmosphere. You can weld structure and do a live reality check, so to speak. Evaluate which ones really are going to be the best for you.
Pete Koegel:
Interesting. Say it’s a boiler application. You could put something right on a boiler tube or boiler wall on a specific elevation where you’re seeing a combination of specific temperatures. And you can put a couple of your sample bars on, come back and take a look on the next outage and see how it lasted, see how it flaked.
Marc Glasser:
That’s exactly correct.
Pete Koegel:
Oh, that’s really cool. I didn’t realize that you guys offered that service. On our side of the business, a lot of those decisions have been made. Obviously, on our engineered products, you know, we’re making those decisions as we work to improve those, be it in our power parts or our autoclaves. We worked with you guys a lot with the 253MA material that we offer in our tips for the coal fire plants. But in a lot of our custom fabrication and nuclear and the chemical industries that decision’s kind of already made by the plant engineering group. So we have the expertise to fabricated welded machine and make sure that those properties are sustained throughout the fabrication process. But it’s interesting to hear a little more background on, how some of those decisions are made and what resources are available to someone who’s trying to make that decision.
Marc Glasser:
Let me add a couple of more features on this. First of all, those two services, I just talked about the metallurgical investigations and the sample program. Those are services that we offer to our customers at no cost. That’s a service we provide in line with our philosophy that we want to be real business partners, not just another supplier. So we go the extra mile to give you useful services that you can take advantage of to put yourself in a position of advantage.
Pete Koegel:
So something like $50, a pound material, you’ll send me a little coupon that I can weld into my boiler and, and investigate actually as a free service for you guys provided you get the opportunity to get the feedback and the information on it, because it’s also a data collection point for you guys as well, right?
Marc Glasser:
It’s a data collection point number one, and number two, the way our relationships work, it’s the old saying, one hand washes, the other. We help you solve a problem. It’s our goal that you’ll come back to us. If we help you find the solution, you’re going to come and buy the solution from us. Everybody wins.
Allen Stoltzfus:
Yeah. It really sounds like a lot of value added resources. In some experiences going out from material company might be like, yeah, this is what we have. And that’s kind of where the conversation ends. But as you said, Mark, when you can really walk through it with the customer, whether that’s an engineer on whatever level and really help them make an educated decision, then you’re definitely gonna be the first ones they go back to when they actually need that product.
Marc Glasser:
That’s correct. And then the other thing, and I will throw this out to you and anybody who’s listening. We also want your help because in the course of the manufacturing activities, and it’s an old cliche, but it’s true. Everybody will call you when there’s a problem. But when something works, people forget to let you know. So I always tell people and still don’t get a lot of good feedback on it, but when something works well, we need to know that too, because that helps us do our job better. It helps us serve you better. So something we discuss with you and help you with works really well, let us know so that we can, we can learn from that too. We learn from what works we learn from what doesn’t work. We need both.
Pete Koegel:
To take a step back for ourselves and anyone that’s listening, just some kind of general families that people might be familiar with, you know, 300 series stainless steels, that’s kind of your basic corrosion-resistant alloy. The world is using more and more duplexes today, which is kind of your next step up in my opinion, chloride resistance, a little higher strength characteristics, cause it drops some nickel. And then you start kind of walking into the big room of nickel alloys, which just is a kind of a huge broad spectrum. And you kind of touched on it there between corrosion resistance and heat resistance. Someone that has a highly reactive chemical that they’re processing is looking for. Something that depending on the operating temperature may be in a reactor, is looking for something might be more corrosion resistance, maybe that’s resisting some type of acid or acidic environment versus something that might be operating at let’s say, correct me Mark, maybe 1200 degrees, maybe 1500 degrees might be the window that you would start looking into a high heat resistant alloy that would have some increased oxidation resistance and creep resistance over a standard, 309 stainless steel.
Marc Glasser:
Let’s back up a little here. When we start talking about the heavily corrosive environments, you’re correct. The 316, the 304 commodity grades, the most commonly used stainless, your next step up or the duplex materials. And there’s basically three categories is lean duplex, there’s duplex. And then there’s super duplex. Step up, you get increasing resistance to chlorides and that’s in terms of concentration as well as temperature.
Pete Koegel:
And actually, we’re offering our autoclave, our beta star product line with the option for duplex chamber because of the chlorides that we had started to see in customers’ process water.
Marc Glasser:
It gets more interesting in there as well because the duplexes as a family, have a much higher strength level. So you have the opportunity with glued design engineering, potentially going to thinner wall sections the differential can be reduced or minimized by designing something to handle the same strength with thinner materials. That means lighter materials, less weight. The customers have because you’re going to get more life. And it’s only more expensive at the beginning. Not more expensive over the life of it.
Pete Koegel:
And you’ve talked about that before, as far as the total cost.
Marc Glasser:
That’s my mantra life cycle costs would be the right word.
Pete Koegel:
For someone trying to plan a new design or a replacement. Can you talk about that a little bit in some of your experiences that you’ve seen in downtime for replacement. And obviously, everyone looks at the big capital cost upfront. That’s the thing that you’ve got to justify that they got to hang their hat on.
Marc Glasser:
We have beyond duplexes. The next step after the duplex or the super austenitic that starts with 6 Moly Steel and that brings you to a higher concentration of chloride that these metals can resist. The alloy there would be AL6XN alloy, and above that to the next level would be alloy 625. And then you can go even beyond that. But those are beyond the alloys that we get involved in. There are alloys that can go beyond 10% chlorides and still offer resistance.
Pete Koegel:
Inconel 625 is kind of the household, high nickel alloy grade, right.
Marc Glasser:
That’s correct.
Pete Koegel:
And that’s probably been around for quite some time.
Marc Glasser:
Yes.
Allen Stoltzfus:
So Mark, question here. If I was, let’s say an engineer and looking at some different material options and I were maybe to go on your website, what kind of literature or information do you have available? If I just had some basic design constraints, maybe that’s some temperature or what kind of chemicals running through the metal and stuff too, you know, in order to make a ballpark educated decision of what I need, you know, whether that’s 304 stainless steel or super duplex or just anything across the board.
Marc Glasser:
Very good question. You actually transitioned me into the next point that I was going to make that when you’re dealing with these, corrosives, there’s two primary factors that you have to consider. We talked about the first one, that’s the concentration, but the second one that’s just important is temperature. So now we talk about resources with the chlorides. We have some of it online, but if you do the call in, call the metallurgist of send for metallurgical help, we actually have graphical data that can show you the progression and where one ends and where others can extend. We have tabular data that shows you what alloys you can use for different concentrations and pH combinations. In your industry, it’s most apropos because it’s designed for the flue gas, the sulfurization systems, and the tables are specifically for that application. On some of the more complex alloy, we actually have what we call ISO corrosion diagram. Those are diagrams where you have temperature on the Y-axis. You have concentration of your corrosive on the X-axis. And generally, you have an ISO corrosion line, which is drawn on the graph at the point where you get a generally accepted corrosion rate. I believe it’s five mils a year. Some of it might be 0.1 millimeters per year, but they’re generally accepted numbers. It’s usually shown on the table. The line goes through the combination of temperature concentration, and it shows you the point at which you hit that level of corrosion. If you’re below the line, your corrosion rate will be slower. And if you’re above the line, your corrosion rates going to be higher and you can’t always predict how much, but you can, you got a good feel for what alloys are going to work and what aren’t. We have that on our website and we’ve actually broken it into three sections, low concentrations, mid concentrations, and high concentrations. There are some surprising results when it comes to sulfuric acid, particularly in the dilute and very concentrated sulfuric acid. We find there are super duplex materials ZERON 100 is a very good option for many applications. A more complex acid would be hydrochloric and that one is not online, but we do have resources you can share with customers through ISO corrosion diagrams. And again, at the very dilute concentrations, probably less than a percent and a half at temperatures up to boiling, we have a couple of options that can be used. Beyond that is beyond the Alloys that we have, but we have the resources to point you in the right direction of what potential alloys could be used. And depending on the particular area of the curve you’re operating, we might even be able to point people to other places where they could find the materials for more severe.
Allen Stoltzfus:
Yeah, it’s good information. And it seems from my end, what I’m hearing is I can go on your website and get a basic outline of what I need, but should it get any more technical than that? You, it seems like you definitely have yourself and others that are, willing to answer a lot of questions and really get way more in-depth than something I can read off of a PDF somewhere.
Marc Glasser:
That’s one of the services we offer. And again, we can be called directly on our phones and there’s also an email metallurgical-help@rolledalloys.com. That will come to our metallurgical system and we try to answer them all within a day or two. If it’s a more complicated situation where it’s going to take some resources, we will try to at least let you know that we got it, and we have some work we have to do to look up some things we have to do some research, but we acknowledge that we’ve gotten your request and that we’re working on it. Where it gets really complicated. Now on the corrosion side is we’ve talked about aqueous corrosive. Once you start going up in temperature and we’re seeing more and more of this, you start getting into the areas where you’re starting to boil things off, and then you go into heat, exchangers and things cool down. It’s a vapor phase and you can get condensation. That’s where things get really tricky. That there’s no easy answer. We have a lot of reference books. We have a pretty good network outside of rolled out, was with people that we know, if we can’t come up with the answers on our own, in all our reference sources, we have other individuals that we can go to for assistance too, that have access to data that we don’t have.
Pete Koegel:
Do you guys offer just cobalt specific alloys? You know, we don’t work a whole lot with cobalt. I mean, there’s cobalt as an alloying element in a lot of the materials that we fabricate with. Some of the higher end nickels. But specifically cobalt. What does that do as an additive or as the primary alloy itself?
Marc Glasser:
Good question. Give me a second. I actually have a reference book here and I want to read out to you what it says, because it actually explains what each element is used for. So here’s what it says about cobalt. Cobalt at the 3% level improves strength slightly and enhances oxidation resistance. Larger amounts, 15% or more, give you a significant strengthening effect at high temperatures. Some of the cobalt alloys get very strong, but they’re only oxidation resistance up to about 2000 degrees, some only 1800 degrees. Cobalt oxide is softer than chromium oxide, which is the typical oxide, which is the first layer of protection, and many of the corrosion and heat resistant alloys. The cobalt oxide is softer and somewhat lubricating. So at elevated temperatures, they’re less likely to gall than the nickel alloys. Cobalt is an austenitizing element like nickel. But it’s also very costly. It’s quite a bit more than nickel. So the high cost generally limits cobalt alloys to gas turbine. The other thing, when you’re looking at nickel versus cobalt, that’s, if you get into sulfadiazine atmospheres, particularly reducing sulfur for most other environments, when you add nickel at the expense of iron, you increase oxidation resistance, you increase carbonization resistance and you increase nitriding resistance. So nickel is like the magic bullet for many things, but not sulfur. Sulfur is the oddball element. Sulpher can be very nasty. And when sulfur reacts with nickel, you get a very low melting eutectic. And that happens at about 1,175 degrees. And then you see that liquid phase forming, and it just kind of eats away at the alloy in the location where the sulfur is hitting the alloy, and it’s a really reduces a life. So if you have sulfur generally, what a lot of people do, they’ll, they’ll go back to a lower alloy in the stainless range. But as you know, with the process is going on now in the efficiencies people using higher and higher temperatures and the traditional heat resistant stainless steels like 309, 310 and even 253MA, which has good resistance to oxidizing sulfur, like Stainless SS02 when you start getting above 2000 degrees, they’re not hold up that well in terms of oxidation and in, in terms of strength with the exception of two 253MA. So now you have to find a completely different mechanism. And one such mechanism is the consideration of the thermal dynamics of the oxide layer. I briefly mentioned that chromium oxide is the main oxide in the first level of protection and the heat resistant and corrosion-resistant alloys. Some of the more designer alloys, if you will employ additional elements to create suboxide, in the case of two 53 MMA, you have a Silicon addition, it gives you a very thin layer of Silicon dioxide. And then with rare earth metal addition, that makes it very adherent to the base metal. So it gives you a very tight adherence outside. That’s going to give you very good resistance to things up through about 2000 degrees, particularly oxidation that sat outside shield with the Silicon. It’s still, it’s good for oxidation other things it’s not as good from a thermodynamic standpoint against software. It’s better than the chromium, but it’s still not going to be adequate, but then you go to the next layer and that would be aluminum instead of Silicon or a 602CA alloy. That’s 2% percent nominal aluminum. And the level you have enough to form a very, very thin continuous layer of aluminum oxide, which is extremely thermodynamically, stable, even against sulfur. We’ve seen applications at 2000 degrees and above where that oxide will give you resistance even to sulfur. Not going to last you forever, but you’re talking anywhere from eight months to almost a year, depending on the temperature and the concentration. Whereas other hours might last a month. Transitioning back to your original question with cobalt. We’ve seen some cobalt alloys where they give additional resistance to sulfur. Again, I’m not an expert in the cobalt alloys, as I am the nickel alloys, but there are a couple I know have been used successfully. Again, they’re not going to last forever, but you might get a year, a year and a half on them at very high temperatures and a lot of sulfur.
Pete Koegel:
A lot of people might be familiar the 309 Stainless and the 310 stainless and the RA602 is essentially on the, on the other end of that spectrum, would that, would that be kind of the highest end heat resistant alloy?
Marc Glasser:
That’s like our Cadillac or a rolls Royce of the heat resistant alloys in our portfolio. Some competitors, also have their own versions of aluminum was where they actually go to a significantly higher aluminum, the problem with aluminum and the other alloys that will give excellent resistance to sulfur is chromium. But you’re limited in a wrought rolled product. And in your case an alloy that you want to fabricate that you want to bend and do all kinds of things to shape and weld, you’re limited on aluminum and chromium because when you get beyond certain limits and percentages, the alloys always become hot short, which means their ductility drops drastically. So you really can’t hot work them. You can’t roll them, you can’t forge them. So your only options are casting or powder metallurgy. That’s why you don’t see 10% aluminum wrought alloys.
Pete Koegel:
Cause obviously you always learn, you know, from my background, welding engineering, you know, you’re starting out with a minimum 10 or 11% chromium to get you into a stainless family. And then you kind of go on from there, but we work with the nickel 200s, nickel 201’s, which are essentially a pure nickel, but I guess I’ve never really thought about the pure chromium or, exceeding chromium say 25% of what’s the 309. Is that, is that in the twenties?
Marc Glasser:
I believe the 309 stainless is I want to say about 20% chromium. The 602CA alloy has about 26% chromium, I believe. Unfortunately, I don’t have all the numbers in my head, but my brain is like a hard drive. There’s only so much, but that’s why I have my reference. 25-26%. If you start going beyond that, you’re going to start having difficulty rolling and hot working the materials, to get them into wrought form.
Allen Stoltzfus:
Most of these alloys that you offer are these proprietary materials to Rolled Alloys and are other companies offering similar or with some of them is exactly the same product.
Marc Glasser:
We have five, what we consider six, I should say six alloys that we call Rolled Alloy’s proprietary alloys. We use the RA before it, we have a trademark symbol for it. Some of them we’ve developed some of them. We have exclusivity arrangements with manufacturers, but there are other manufacturers that have similar knowledge. They have different chemistries, they do different things, but they’re trying to get the same point. Again, what makes rolled alloys unique is that we have our metallurgical staff. We work with the mills. We work with the customers. So we have the knowledge from the entire supply chain from manufacturing customers use it and the applications engineering that we can support the alloys. There are times where we much to our chagrin. We will have to tell you that there are better options on what we can give you, but when it gets to that point where you’re having such a complex system, those options can be, be materials that have a 60, 70, 80 week lead time. So if you’re doing capital projects and you know, far enough that you need that alloy, you can plan accordingly. But if you have a situation where you have a piece of equipment in the field and say, you’re operating at a high temperature and lo and behold, you formed some kind of sulfuric acid or another reducing sulfur for the literally each through the wall of your thermal unit. Well, you need something right away to patch it until you can build a new one. That’s where we can come in and help you. We have some of these materials, most of these materials we stock so we can get just some of them may not be as good as what you built it out of, but we can have it on the road to you in a day or two or a week. If you have to have the process to a certain size.
Pete Koegel:
That’s one thing Allen’s worked a lot in a couple of projects here recently. Say a designer or mechanical engineer coming up with a new design or redesigning an existing piece of equipment for a new service. And they found the perfect alloy, the alloy that meets the corrosion or heat or strength, or all combined, typically resistance, but it is normally a very unique alloy, but they have standard couplings, flanges pipe, product forms, you know, incorporated into that and ends up being our task to try to be creative with how we can make those parts, how we can find them. Cause a lot of these things aren’t necessary, you know, in forging or in a, in a flange sitting on a shelf somewhere like for example, is RA602 alloy available in a, in a pipe form or in a, in a flange form
Marc Glasser:
Unfortunately the 602CA alloy is not really extrudable for small pipe. When you start, if you’re thin enough wall, we have fabricators who can form it into pipe as small as two inch diameter and weld it. And for flanges, you could perhaps machine a flange out of a plate and welded to a pipe.
Pete Koegel:
That’s what we ended up looking at or going to a different flange type of design, for example, like a lap joint flange, where the forged part itself wouldn’t be processed. And, you know, we can kind of design our way around that, but it’s just, you know, something that we ended up kind of coaching through with, in most cases, it’s budget quotes, it’s kind of R and D and development. They’re trying to get costs, but it’s something that it’s definitely, everyone needs to take into consideration. We’re always willing to offer, overlay options or if you had enough lead time, there’s a lot, a lot more unique things you can do to get the product.
Marc Glasser:
That’s correct. And there are processes you hit on one, overlaying. You have coatings industry where you can thermal spray things. We worked with one company that can explosively clad materials. There’s a lot of unique processes.
Pete Koegel:
And normally the balance is time and budget. Right.
Marc Glasser:
You know, we have our own little metallurgical humor. If you will. We have competitors that have two trademark alloys, we call them unobtanium and non-existingium. Unobtainium are the things that take the 50, 60, 70 week lead times and oh by the way, these alloy are so complex. Forget about making flanges or elbows or couplings. You can have the plate, you can have the sheet, you might be able to bend on with a very generous radius, but that’s the best you can do. Those are the ones that we call Unobtainium. And then I get a call. Do you have a nickel base alloys that can withstand 3000 degrees Fahrenheit? Yes. We call that non-existingium, because at that temperature it’s going to be a liquid, not a solid.
Pete Koegel:
Nice, that’s good stuff.
Marc Glasser:
We can laugh about it. But the fact of the matter remains, I’ll probably get four or five, six calls a year where people are asking for non-existingium and then they’re shocked when I tell them that it can’t work. And then they’ll ask, well, what about something like moly or tungsten that has a really high melting point. Yeah. Tungsten. It has a melting point of about 3,500 degrees centigrade. What are you going to use it in a vacuum? No. Why? Well, if you’re about three, 400 degrees centigrade for any, for more than a, more than an hour or two, you’re going to get the most beautiful Canary yellow powder because it oxidizes completely.
Allen Stoltzfus:
That’s exactly the kind of conversation that’s great to have early in the development stage. And you know, sometimes we get projects where that’s what it is, but other times it’s something that’s further developed. And if we can get people to be having these conversations, we can coach through a lot of people with some of the more basic stuff, but for some of these really complicated questions, as it is still in the design stage, it’s, it’s great to get them in front of someone like yourself or others that can really offer different solutions for this.
Marc Glasser:
We have the most success when we work with people like you and the other fabricators we deal with early on. And we can ask you all these questions early on, and then you’re a competitive advantage because you know, the answers, you know, what alloys to use and then we win together.
Pete Koegel:
No, it’s kinda been a specialty of ours over the years that we’ve invested a lot of time and weld procedure development and just the power sources, you know, welding power sources and equipment and machine tooling. Sometimes we try to outsource maybe a small little Inconel part and most, little machine shops, smaller machine shops don’t even want to touch it because it’s so hard and gummy and as far as manufacturability it’s, very unique. So yeah, this was a really good breakdown, especially on the selection side. What’s a crazy story you’ve run into in your say, 30 or 40 years of doing this other than the unobtanium calls. What’s one of your top three unique situations that’s been presented to you and maybe something you guys even help with that solution.
Marc Glasser:
This goes back maybe five years and I was in Asia. We are a global company. We have divisions in Asia. I was with a customer of ours in Asia with our representative over there. And they were using one of our materials for pressure vessels, that they were welding. And I knew this was coming up a week before I went there because they asked me for a welding manual because they were cracking all their welds. So that particular manual bulletin, you pull up on our website and probably two-thirds of this bulletin just discusses good welding practices and there are illustrations of good, bad. I went in there and they, again, all the welds are making a cracking. The first thing it says in the first sentence is, do not ever preheat this material when you weld it. Make convex welds, keep heat input low. So I go into this shop and they’re cracked and they’re all mad. And they start yelling at our sales representative. Everything’s cracking again. And so I don’t speak the language. So our representative is serving as a translator. I asked him through our representative, did they receive the welding manual? And if they follow the good welding practices, and so they speak, they come back and say, yes, we’re following every practice in the book. And I looked at him and I looked at the welder and I said, no, you’re not. And he got really started screaming at me in the foreign language. And our representative looks at me very sheepish. She says, why would you say they’re not? And I point at the welder and I told him, tell him right here, the first thing it says, do not preheat. And the welder sitting there with a torch, heating the material. And as I watched what they were doing, I looked at the weld that they had everything that we said do not do, they did. We say when you get to the end of the weld back step for an inch, don’t stop, but you hit the end, go back in the other direction for an inch. So you don’t get an abrupt pause to give you a star cracking at that weld end. Well, you could see the weld just stopping. I mean, I could have taken that picture of that and put the actual photo in the manual. Instead of the hand drawing that was made 20 years ago, that’s how blatant it was. It says interpass temperatures should not be more than 200 degrees. So they had waited about 45 minutes and they want to start up again. I said, well, hold on a second. It was a pretty heavy plate. So what’s the matter. So I walked out where the welder was getting ready, said, stop it and move them away. And I looked at the plate and I spit on it. My gob of spit evaporated lickety-split, you can’t weld yet.
Pete Koegel:
So that was your temp stick.?
Marc Glasser:
Exactly. And they looked at me like, what the heck are you doing? I said, it’s too hot. That’s boiled up. So that has to be at least 300, 400 degrees. I have to wait another two hours for it cool down enough. And at the end of about four hours going through this whole process, the guy finally goes out and he welds it. He finishes welding and he looks at me. He goes, it’s not cracking.
Pete Koegel:
Oh my goodness. Yeah. Everyone might think it’s just like welding a stainless.
Marc Glasser:
So there’s a lot of similarities between nickel and stainless welding or austenitic 300 series welding. So the thing that I’ve learned is oftentimes your most experienced welders have more of their experience with steel and at least on your prototyping, those are exactly the guys that you not want to develop the processes for stainless and nickel, because what you have to do to make these specialty alloys work is exactly the opposite of what you would do with steel. These guys have so much experience what you have to do on stainless and nickel runs so counter to what they’re used to, that they can’t wrap their hands around the fact that it’s a very different material. So you want somebody with a little less experience who’s willing to listen.
Pete Koegel:
We actually had a project where we use a, kind of a new welding technologies called K TIG. Have you heard of that yet? Mark
Marc Glasser:
I’ve heard of that is that’s like an automated process.
Pete Koegel:
It’s like a key hole TIG process. So they do something within the dynamics of the electricity. So you can punch through say a three-eighths thick piece of Inconel single pass without filler and get a full penetration, a hundred percent X-ray just beautiful weld. We had an application. It was actually in a high-temperature part that they were using. It might’ve actually been RA 602 that we were building this out of that we were working with the process engineer that spent a lot of time justifying that material for their equipment. And, was a little hesitant to see the use of this new, welding technology on it. And it was just a cool interaction with the process engineer. Cause we, we had to do a procedure qualification on it and the metallurgy and the microstructure and the ductility and the how limited heat affected zone there, was in this part with the new process kind of surprised us how well it worked, but that’s kind of on the opposite end of the spectrum to what your experience was in, that Asian fabricator.
Marc Glasser:
So you don’t have that in your facility.
Pete Koegel:
We do.
Marc Glasser:
Oh, well, next time I make my East coast trip. I may have to just come and visit you because I would love to see that because I’m not familiar with it. And if you’re amenable, I’d like to come and see how it works. And maybe you could weld a sample up that I can play with and look at and learn from.
Pete Koegel:
It’s been a really good fit for us primarily in the stainless and nickel alloys world. And it’s pretty cool technology.
Marc Glasser:
Well, either this summer, when I do my trip in late January, early February, we’ll have to talk more about me coming in and see.
Pete Koegel:
Yeah, yeah, absolutely.
Marc Glasser:
But I would like to transition into one area that you had kind of hinted at that we want to talk about and that’s the heat resistant areas. And if I can move to that topic, we had, we had talked about discussing the factors that are important to consider when you’re choosing a heat resistant alloys. So let me jump into that. So for me, when I consider that there’s generally four primary criteria, then there’s a bunch of other considerations, but the major criteria, on our part, number one oxidation limit. And that’s basically when these metals get orange or yellow hot, how high can they go where they will still re resist the hot air that surrounds it. And we measure that in the lab. We have a whole protocol that we use in our lab. Different companies use different protocols, but what I’ve seen when I survey the various websites, they’re pretty accurate. And they’re repeatable from one method to the other almost all the time. It might be one or two alloys that are exceptions, but there’s pretty good agreement from different manufacturers who do different methods. We have our own criteria that we use, we can test it in the lab. We do competitive tests. Certainly, if you have some alloy that you’re using and you want to use one of our alloys that are a little more available, can withstand the same thing. We can put it in our furnace. And we have a whole protocol that I can review with you. If we get to that point to do the evaluation. We have a graph, I think you saw it where we have the stack alloys from stainless on the top, the highest nickel on the bottom to show you what the oxidation limits are. Basically, be about 1500 degrees for the 300 series stainless. You start getting into lower performance nickel, alloys talking 1800 and the heat resistance stainless go from 1900 to 2000. When you start getting into nickel, alloys, and you’d show oxidation resistance from 2100 up to 2250 and 2250 would be the RA602CA Alloy.
Pete Koegel:
So people understanding where they fall, primarily starting with the temperature, right?
Marc Glasser:
That’s correct. And if you go on the website and you see it can be used up to that temperature, a lot of websites say it can be used up to a certain temperature. That’s somewhat of a misnomer because that’s really the oxidation limit.
Pete Koegel:
It’s not the strength characteristic,
Marc Glasser:
It doesn’t count the strength. So for instance, it might say 310 Stainless Steel, for example, it can be used up to 2000 degrees. Generally, consider the oxidant limit of 310. Oxidation is only one factor. The next factor is creep strength and what is creeps strength exactly. Let’s talk about what creep is. Designers know that with carbon steel at room temperature, you pull a tensile test. It has a yield stress. It has tensile strength. If you exceed the tensile strength, you basically break it. Your yield strength basically means that if you pull on it and don’t exceed the yield strength if you release the load, the metal goes back to the exact shape it was in before you loaded it. It’s elastic. There’s no permanent deformation. If you go beyond the yield strength and you let the load go, it’s not going to return to its original state. It’s going to be a little longer and maybe a little thinner. I’m not a mechanical engineer. I’m not an expert in designing, but generally, the design criteria is based on the yield strength for those safety factors involved. And there’s a lot of data for yield strengths at a higher temperature, where you basically running a tensile test inside a very tightly controlled oven, that’s just around the part, but not around the grips that you’re pulling it. And so you get a short term tensile, and short-term yield. If you base your design off on that. Well, what happens when you, when you sit in that hot environment a few months, that metal is going to stretch and deform on its own because it’s at a high temperature you’re talking about months and that tensile test is done in a matter of a minute or two, as it’s sitting in temperature longer, longer, it’s gonna yield at a much lower stress level.
Pete Koegel:
I always understood a creep was essentially you’ve got slip within the microstructure level, you know, tension over time.
Marc Glasser:
Well, that may be a little too complex. Let me try to make an easier analogy. We, we show this in our literature. If you take a six-inch pipe 602CA and you take RA330 Alloy, and then you take 321 Stainless Steel and a 309 Stainless Steel and you put it in the furnace at 2100 and you leave it there for a couple of weeks. The 602CA is going to be a perfect round. The RA330, it may deform a little bit. It may go from a little round to slightly elliptical. The 309 Stainless Steel is going to start looking more like a football and that piece of pipe in the 321 Stainless, it might be one straight piece of plate with two layers to it and a little gap in the middle. That’s the lower alloys that have sank from their own weight there sitting in the atmosphere. That’s creep. Creep resistance is the ability to resist the self-movement. And there’s actually a test where you actually, it’s similar to tensile test, but you don’t keep pulling it with increasing load. What you do is you load it with constant pressure and temperature and you watch, and you’ll have three stages. One will be like an elastic deformation and a steep line, and then it’ll level out. And it’ll be a very low slope curve. It could be for weeks. It could be for months, depending on your stress level. At some point, now you’re going to go into similar with Tansel, where it’s just going to go steep again, a break. But most of the life of that part of the temperature is going to be very, very little deformation. Once you get the initial yielding out of the way, There are ways to interpret it, but creep strength is the ability of the material to resist of minimum strain rate. The higher the creeps strength is, the more force you have to apply to get a certain minimum creep rate and the stronger it is at that temperature. So you want the higher, the creep strength the longer it’s going to last. It’s not a linear kind of thing. And it’s going to vary. There are guides and I could spend hours on this topic, but in general, what you want is the higher, the creep strength, the better you are typically in the furnace building applications. The numbers are basically, you’re looking at the strength at 1% and 10,000 hours. It takes something like 309, 310 at 1900 degrees, 2000 degrees. You don’t have any appreciable creep strength. And what creep strength you have is going to be maybe the 1% and the thousand-hour range while a thousand hours about a month. So,it gets really crazy and it’s much more complex than that. So I’m trying to simplify it as much as I can, but if, if that’s that big of a concern, you could talk to me and we can walk you through it. And if you really need more complex things, I can put you in touch with some mathematical modelers who can do predictive studies on how things are going to creep.
Pete Koegel:
How do cycles play into all this? Initially here, we’re just talking constant temperature, constant pressure. How does, cyclic service play into heat resistance? Is there considerations in an alloy?
Marc Glasser:
That’s a harder question to answer. I do have certain customers that believe the more you cycle it, the less advantageous, some of the better alloys are. I think that that more plays into some other factors. Theoretically, the worst things are going to happen at the higher temperatures. If you’re gonna spend most of your life at lower temperatures cycle up every once in a while and cycle it down, that shouldn’t hurt it. Unless you’re going to do a lot of cycling and you’re constrained. That’s another factor is when things are constrained and you have one part that’s hot, one part that’s cold. Thermal expansion is a material property that is dependent on temperature, the higher, the temperature of the it expands. But when you have a piece of commercial equipment and you start cycling it, some parts are going to cool faster than others. If things are not free to move, as they want to expand the contract, this competence is change. You’re going to have stresses applied to them from the constraint when it’s constrained like that. And something wants to move, either pull in or push out. One of three things can happen. It’s going to bend, it’s going to buckle or it’s going to crack. So I think one of the things that designers fail to take into account is thermal expansion. So if you’re going to be doing a lot of cycling, I think that the key is you have the design it to allow the components to move freely, because if you constrain it; you might have the best alloy 602CA, that may bend more because it’s so much stronger that the hottest part can’t push it can’t expand or can’t contract. And the cooler part is so strong that the only thing the hot part can do with bend, that’s going to bend more than a lesser alloy where it may bend more in the colder part. So the severity of that whatever’s going to happen is going to be less.
Pete Koegel:
We’ve spent a substantial amount of time, especially in our coal nozzles and air nozzles. Cause it’s a, we’ll call it a fully constrained structure, you know, at various temperatures all over it. So we kind of see that on outage results all the time and how we can better improve that. Essentially, we always come to the conclusion that there’s no stopping thermal expansion. It’s going to go somewhere that’s how it is? How are you going to deal with it?
Marc Glasser:
Again, there’s a couple of things; you can allow it to freely constrain or you can design a mechanism. So there’s a portion which is free or to move. And you know, it depends on what your design is. If you can put a notch in it and you’re not restrained because you have to have an airtightness, you can put a notch in it and the notch will move and hopefully take most of that. And there’s a void where material can move into. The other thing is, I don’t know what the right technical term is, like a shock absorber where we corrugate it in a direction, it’s like a spring. So that’s bringing him moving and pushing and pulling.
Pete Koegel:
Yeah. We’ve, we’ve explored a bunch of those different options and like everyone within a lifecycle of equipment is it gonna make it say to the next outage? You know, cause there’s a gap that you’ve got to close for it to make sense, to either risk changing the design or increasing the cost of that material. Because it’s not just in most cases, most plant level based. It’s not, if I get another day that’s another day, well you got to potentially make it to the next outage cycle and the next maintenance schedule within the year with visions to, to actually have that, that return on investment.
Marc Glasser:
And that’s one of the things I’m learning as our better materials are starting to be accepted. People don’t design that in you can actually get lower performance and it’s not because of the metal it’s because of the design of how things are put together, where metals join other metals. That is the secondary considerations that I was going to talk about, we’re talking about. And then I’m going to segment back into the other two we were talking about. So, so that’s another one, but then you can get into a situation where, well, on paper or RA253MA it’s got higher creep strength than RA330. It’s lower cost than RA 330. And somebody would say, well, man, that’s just great, but you have the next consideration. You can form brittle phases at certain temperature ranges. The most common one is called sigma phase. And sigma phase is an intermetallic compound. It’s an iron-chromium compound and it’s, a precipitate and precipitates are hard, strong and brittle. So you can form sigma phase generally between 1150 Fahrenheit and 1600 Fahrenheit. There’s kinetics as well. So the real weak spot where it forms a quickness is about 1300 degrees. And that could be in a matter of a thousand hours or so. The limits lower or higher, it may take 10-20,000 hours. And what happens with signa phase is at operating temperature. It’s fine. So if you’re going to be running, say continuous, nozzle, or a muffle. And it’s always going to be a temperature. You’re not going to have a problem. It’s going to be a 1200. You’re not going to have problems because the signal phase doesn’t brittle at that operating temperature. Now you cycle it off, bring it down to room temperature. Now it becomes very brittle, like a piece of glass. And again, if I can relate a story, there was a company and this was before my time, but it’s one of those urban legends where they had 310 muffle. It wasn’t an overly high temperature process, continuous furnace. They didn’t realize they had sigma phase in it. And it was starting to bow a little, well, they said, well, let’s repair it. Let’s jack it up and press it back into shape. So they had these jacks that they put in and they had hydraulic long arms. So they could hydraulically raised a Jack and try to push it back up and the jacket, boom, boom, boom. And all of a sudden you hear bam in the thing split. And it broke like throwing a rock in a Coke bottle. That was Sigma phase. And it literally shattered into thousands of pieces because at room temperature that Sigma phases, so brittle that your ductility is, is reduced to almost nothing. If you’re going to be cycling, going to be on, it’s going to be off, you’ve got to take really care room temperature that you don’t overstress it. And more importantly, you don’t impact it because of what’s ductility. It’s the ability to resist an impact. That’s why you do sharpie testing, right? So picture this, you’re a heat treating shop. You have 253MA Steel or 310 Stainless fixtures. Not a lot of heat treating shops, pick up a fixture or a basket. And they bring it from one place to another. They had this little piece of equipment called the forklift. Forklift drivers aren’t really careful. And they go bang. And that basket breaks. Well, we’ve learned through experimentation and experience that when you add nickel and you hit about 34, 35% nickel, you don’t get sigma phase formation. What’s 35% nickel RA330. That’s the minimum alloy where you can use and not get sigma. And that’s what mostly heat treats shops have baskets are made out of RA330. They might have a cast on the bottom. It may be completely RA330, but they use RA330.
Pete Koegel:
Interesting. I guess I never realized that component of that being the resistance to Sigma phase and even using equipment, both at room temperature and high temperature, you know, even to move stuff, to lifts stuff. So that’s interesting.
Marc Glasser:
One of my predecessors, a gentleman that worked for us for many years, his favorite saying was the number one cause of failure in heat, treating baskets and heat treating shops as forklifts. He had a lot of these little anecdotes that we’ve used over the years. And then, so, sigma the phase is important. Last importance is, as we’ve talked about in corrosion, resistance is what is the environment? If you’re in air, well, then you know, your oxidation limit rules and then you creep strength rules, but most heat treaters, they’re not air atmospheres on the insight you have carbon-based gases, carborizing processes. You have nitriding processes, those two processes. What can you add to an alloy to increase the resistance to corporatization, to nitriding? It’s real easy, it’s nickel. So you start increasing nickel and pulling out iron and that’s what you do. That’s why I said before, much of the time nickel is the answer to many problems except sulfur. That’s why you see all the nickel alloys. Now creep strength gets a little more complicated. I think the things you can do to increase creep strength are beyond the scope of what I want to talk to today. But we do have insights. If somebody wants to engage me in a conversation with that, again, I would encourage people call me directly at my 800 number or at the plant number. And we can talk about that. But it’s beyond where I want to be today. And those are the four major factors to consider for heat resistant applications. It’s oxidation limit creep, strength, do you, or don’t you get a brittling phase and can the alloy withstand the atmosphere that it’s going to be under. I want to send a cautionary note when people say, well, my processes 1800 degrees, let’s say 1750. I need an alloy that can resist 1750 wrong? Why is that wrong? Because way things heat up, usually heating from an external source. It could be an electric element. It could be a gas firing. The gas or the electric element is going to heat up the alloyed. The alloy is going to heat up the air or the space on the inside the nonsolid space. You have to put enough heat into it that you get the gas in your furnace to temperature.
Pete Koegel:
So they might be thinking of their reaction, temperature.
Marc Glasser:
Exactly. To get that reaction, temperature, the metal to be hotter. That’d be a few hundred degrees hotter. You know, if you design on that, you could get a very premature failure because you thinking you’re at 1800 and you, it might be 2000 or 2,101. This is one of our favorite urban legend stories. You have a guy and he’s been using RA330 for 20 years and he’s never had a problem. All of a sudden he calls you up and he says, we’ve been using this for 30 years. We haven’t changed anything. And was my muffle that was asking me two years is lasting me three months. What have you done differently? Nothing. Well, in terms of the process parameters, that’s true. They haven’t changed anything. They haven’t changed the set points. They haven’t changed their atmosphere. But what happens in business has gotten better. They’re at capacity. They don’t want to invest in a new unit. Business may not be that good. So, well, let’s turn up the rate, but let’s just put 20% more parts to our furnace. Well, what happens when you start adding that much weight to the furnace, you got a much bigger heat sink. You have more cold parts you controller wants that atmosphere to heat up to 18-1700 say. So that thing is just calling to fire it at a hundred percent now, and it’s going, and it’s going. And when you put more weight in it, the burners are going to fire faster. Well, you’re going to be firing longer in a hundred percent. That furnace wall is going to get hotter and hotter. So what you’ve changed, you haven’t changed your process parameters at all. Once you’ve increased the temperature on the metal enough that night, you’re at a much higher temperature and a much lower creeps strength, and it’s going to fail a lot quicker. You have to understand that your mass flow is a variable. You put more mass in, you may need a better alloy and a more expensive alloy to handle it. Or you may need a longer furnace you can run more through it, but you need a longer furnace. So you can walk it up to the temperature.
Allen Stoltzfus:
Yeah, definitely some good factors to consider there that I probably wouldn’t think of. And I’m sure can run right by many people as they’re trying to figure out what the solution is.
Marc Glasser:
Absolutely. And a lot of times, well, everything is obvious when it’s in the rearview mirror when you solve the problem, it’s really easy when you know what the solution is. But if you, if you’re working through it the first time, it can take you years to get through,
Pete Koegel:
To find what variable changed or what you need to change within the equation to make that, that much better of a process. That’s a bunch of great information. I particularly liked this world. This is where I came from in the welding engineering and materials world. So I spent a lot of time here and appreciate the deep dive into any of these topics, Mark.
Allen Stoltzfus:
That was very informative. I know from my background, I have a mechanical engineering degree and you know, a lot of this stuff I haven’t hit on since college, I had some kind of material science class and some different design for manufacturing stuff, you know, looking at cyclic loading and stuff. But it definitely was on a different level and didn’t probably sink in as much as it should have quite a few years ago. But yeah, it’s, it’s a really good you know, take a bit of a deep dive into this side of things.
Marc Glasser:
Absolutely. And that’s why we’re available to call and answer questions. You guys know you can call us, you guys are our customers, so we can work with your customers. In two ways, you can have them ask you the questions and you can call us and ask us for our expertise. Or if you’re comfortable, you can have your customers call us directly. We can do it either way because you’re the customer. I would say how you guys are comfortable with that’s the way it should be done. You can also answer questions. As I said, metallurgical-help@rolledalloys.com.
Pete Koegel:
Great. Well, appreciate the resources. Appreciate you coming on today, Mark. This is a bunch of good stuff. So again, Marc Glasser with Rolled Alloys. Their website is www.rolledlloys.com. And also that that help email, that Mark just mentioned, they could be reached out to. Me personally from the fabrication side, there’s a bunch of good information on their website. You know, they offer weld wires for all their specific alloys. So there’s a lot, a lot of good technical information and resources on there. They’re not just trying to push a product on you. They’re trying to definitely help you with a solution. And R-V we think we, we try to go after these projects, the high, the high nickel alloys, because, you know, we have a lot of experience. We’ve got a lot of qualified welders and procedures on this and, you know, we have relationships like we do with Marc to be successful with them. Specifically, in my tenure, I know we’ve had some very big RA330, RA602, these alloys that need to be very specific in your welding procedures, in your training. You know, they’ve definitely supported us along the way.
Marc Glasser:
We could do a whole podcast just on the technical resources on our website. But again, I want to say thank you to the folks at R-V for allowing me to do this podcast with you, and I hope you and your customers find it very useful. And don’t forget, we’re here to support you guys.
Allen Stoltzfus:
Thanks a lot, Mark. That was a lot of really helpful information.
Rob Hamm:
That was thank you, Mark.
Marc Glasser:
Well, thanks. Hopefully, those stories will help illustrate the points and I can make it fun by relating those stories.
Speaker 4:
Excellent. Excellent information. You just heard from Mark Glasser, a metallurgist from Roald Alloys, along with Pete Koegel and Allen Stoltzfus at R-V Industries. I’m your host, Rob Hamm. And thank you for joining us on this get sparked episode where we get sparked about innovations in manufacturing.
