Pipe Welding Series: Bevel Talk

Times are a changing in pipe welding!

October 09, 2019 Season 3 Episode 4
Pipe Welding Series: Bevel Talk
Times are a changing in pipe welding!
Chapters
Pipe Welding Series: Bevel Talk
Times are a changing in pipe welding!
Oct 09, 2019 Season 3 Episode 4
Miller
Show Notes Transcript

Pipe fabrication leader Team Industries has to stay on the cutting edge to go above and beyond for their customers. Learn how they adapt to new code changes and new technologies with Tim Monday and insights from his experience on the AWS code committees has changed the way he thinks about the pipe industry.  



Speaker 1:
0:01
Thank you for joining the bevel talk season three, episode four pipe fabrication leader team industries has to stay on the cutting edge to go above and beyond for their customers. Learn how they adapt to new code changes and new technologies. Let's get right into it.
Speaker 2:
0:17
Welcome back to bevel talk. Thank you for joining us today. Again, we're joined with Tim Monday from team industries. You know, Tim, we left off talking a lot about um, trends in the marketplace, what's going on, what you guys are seeing in industry as a code body member, but also in welding and heating. So let's take a little bit deeper dive into the welding and heating part of the codes. What trends are you seeing? How have you guys adapted to changes in technology at team industries? Well, I think when it comes to coats in general or even technology, one of the things that we find somewhat frustrating at times is our clients ability to adapt to those new technologies. Very often the clients have come up with a pre established set of specifications. It takes a huge amount of effort for them to change those.
Speaker 2:
1:09
And so as a result, a lot of the new technologies that we see that we think we could benefit from are not, are prohibited or they just don't know enough about it to allow it in their project. So it's, it's, it's really a challenge to sell it to our clients. I often make the joke kind of tongue in cheek, the technology is 25 years ahead of industry. An industry is 25 years ahead of code and how do we combat that? How do we, how do we adapt to that? There's just a comment with regards to code. Um, you know, if the criticism is, is that the code doesn't keep up with technology, I would say that it's deliberate. You have to remember that everything that goes in the code has to have something that's well-proven a good track record. And, and if that doesn't, if it doesn't have a long period of time to evaluate whether or not that new technology works and does service or provides the safety level that is expected of the code committees, then they can't really put it in there until they've seen that proven out.
Speaker 2:
2:10
And so it does, it's deliberate that it takes that long. The other part is, is that, you know, you're dealing with a, a huge amount of experience on code committee and it's one of these people who are reviewing the proposed changes. Perhaps the inclusion of new technologies are looking at that and thinking, well, you know, I remember when this happened or this happened and they have a wealth of experience that they draw from to say, no, I don't think that this is what we should allow just yet. I want to see more time, I want to see some more demonstration that it will work properly. Right. Well, and I think it's, it's, it's important to recognize that and understand that it's not just that that codes aren't, they don't care about technology, but really what we're trying to do and what codes and standards are for is, is for safety and then for service life to be able to extend or maintain service life.
Speaker 2:
3:02
So we know what to expect from a product or a piece of equipment that's put together. Um, so how do you guys at team, with that being said about codes and standards, how do you guys adapt with new and changing technology and welding and heating? Well, I would say that one of the, the probably the biggest change in heating technology is probably induction. Induction has been a great tool for us. But what we've seen, and this is again, one of those things that I've been exposed to as a result of being part of code committee is a lot of studies that have been carried out with regards to heating in this case particularly, um, induction heating. And one of the things that we're finding is that there's uh, uh, the gradient, the temperature gradient through the wall thickness as well as longitudinally direction of the, of the pipe is pretty steep because you can heat so fast with induction and only have electric resistance.
Speaker 2:
4:01
So typically you bring the temperature of that material up at a slower pace. With induction, you can get it up very quickly. And so as a result, you have a huge temperature gradient between where you're heating and right next to it that has no heating. Now, I know that Miller has done some studies on this and they've actually done some, I think L Cheryl's done some some studies on that and written some white papers on it and this is, this is kind of the, some of the, the input that we on code committee need because right now I have the opposite. I have people who are doing studies, heat treatment studies that are really kind of concerned about that whole temperature gradient and how quickly we're heating. We've been employing induction heating and the concerns that I have that I see when we're using it is really to, first of all, we do some induction preheating but what I see is again, the ability to heat so quickly, the temperature dissipates about as quickly as it heats because you have this heat sink that draws away from it.
Speaker 2:
5:09
Right. So a while there will put the induction heating element on there and he'll put the temp stick on there right after that to sail. Yup. It's up at temperature and then he'll start welding. Well in the meantime, just from the time that it, that he's put the temp stick on the time that he's getting his welding gear ready and he's going to start as well, the temperature of may have dropped below the minimum preheat temperatures. So that's a concern that you have to watch out for, which means really you have to be heating for wider area and a larger area than where you're actually gonna be welding. Those are all important things and I think it takes time to understand how induction heating works, how heating works, how the heat sync works to able to recognize and overcome and adapt in your shop to make sure you're doing it correctly.
Speaker 2:
5:58
Right. The other, the other part that's a probably a concern of mine is that, so, uh, it's very regimented when you come to electric resistance heating with regards to thermal couples, the placement of thermal couples and how you're measuring it, right? And when, when you measure that temperature, it, depending on where you're measuring the temperature is either giving you a good reading or bad reading. For an example, let's say that I have a huge flange that's welded on to the end of a pipe. I have a weld between this flange is a WellDoc flange and now in a pipe and you're heating that area right by the wild. Alright. Or in the case of pulsatile heat, treat your, your tree heat, treating that well. Well, if I put a, if I put one thermal couple on right on the top of the world, what will I get right?
Speaker 2:
6:49
How, what about the heat effected zone towards the flange? Do you think that that re reach postal heat treat temperatures right? You have to be able to verify and make sure that it did. Right? So when we use electric resistance, we have numerous control thermal couples, but when we're induction heating, we only have one control thermal couple, right? So it becomes difficult because if you think about the zones and how you heat with induction, you have wraps around it that you're wrapping around the weld. What happens is, is that depending on where I put that thermal couple, which is you know, anybody who was really understanding what's going on, you're going to put more than one thermal couple on there. Absolutely. It's right. It's recommended to you use, you know, 12 three six nine o'clock at a minimum. Well it is, but it doesn't say you have to do that.
Speaker 2:
7:37
Right, right. I see. So, and it depends on whether you go by D 10 10 you know, the requirements of [inaudible] 10 10 heating or you know, what does the client specifying, right. Most of the time they don't say anything. So somebody could just put one thermal couple on at the top of the weld and, and they would have no idea what happened to the rest of the weld. Right. But heat sinks and it's really easy when you have one bar walled that's pipe the pipe and, and there's no heat sinks. If that's straightforward, you can, you can center the, the coils right on top of the weld and there's no problem. A problem really comes in is when all of these heat sinks, whether it's a branch connection or it's a, it's a, you know, a pipe support as well that on or there's a flange, all of those things have a huge effect on how it's heated and remember, right.
Speaker 2:
8:26
Why are we doing post-fall heat treat? We're conditioning not only the weld metal, but also the heat effected zone is a very important part of it as it were. Conditioning the heat effected so, right, right. I think it's, it's very interesting. Um, your thoughts and, and what you're thinking and how and how your thought process is. Because a lot of people that aren't familiar with heating or aren't familiar with codes or aren't familiar with, with welding in general, they'll think, Oh yeah, there's my temperature all the way through, all the way around. I'm good to go. Yeah. And really understanding
Speaker 3:
8:57
heating in general, not just injunction, not just induction, not just resistance heating, but how it is heating work. Why do we heat? What does it do when we preheat? What does it do when we post weld heat treat? What, what are the benefits of that? What if we go out of spec and why it's important is critical to, to a successful operation. Sure,
Speaker 2:
9:17
sure is. And I mean, you think about the, you know, we say stress relieving, right? Right. So what are we doing when we're stressed? We're relieving, right? So, so, uh, obviously whenever you have molten metal that solidifies, you're going to be imposing, shrinking, right? And that's going to be happily as a very localized level. So as it shrinks, you're going to impose all of these internal stresses that are in the weld. Right? Um, the other thing is, is that, you know, you want a condition, you, you, you, uh, raise the temperature in the heat effected zone and you quickly cool it off. Right? Well, if you think about all the processes as steel is made from right, and how it's made, what happens is, is that we have to heat it up. We, we form whatever it is that we're making with the say pipe and we cool it off, but we could cool it off controlled.
Speaker 2:
10:06
We temper it, right? So, so you have to, you have to bring it, you first bring it up to is very high temperature where you're forming it, you bring it back down, now you have to bring it back up, temper it, and then bring it back down. Right? Well, same thing happens in weld, right? And the heat affected zone is untempered so we have to temper it. That's what the, that's what we're doing. We're conditioning that, the heat affected zone as well as well, right? So we're T we're tempering it, but we're also relieving stress, right? So how do we release stress? We raise the temperature until the, the, uh, yield point drops. And so as, as we raise the temperature, we meet the yield point and it yields, now their words gives and it relieves the pressure, the stresses within the weld, and then they can lower it back down.
Speaker 4:
10:57
[inaudible]
Speaker 1:
10:58
the XMT three 50 field pro with polarity, reversing welding system from Miller let's welders change polarity and processes with the push of a button at the stick, TIG remote or wire feeder, eliminating the need to walk back to the power. SARS to swap leads to change polarity, learn more at Miller welds.com/arcreach the science
Speaker 3:
11:19
behind heating is something that just amazes me how much we know and how much we can do to make sure that a weld or a joint or a configuration will do what it's designed to do and intended to do. Um, but how, when misunderstood or misused, it can be detrimental to an entire project.
Speaker 2:
11:39
Yeah. So, uh, I, you know, and maybe this would be a probably a good time to lead into to some of the newer materials that have been used,
Speaker 3:
11:47
right? How, how do you guys adapt to lightweighting and high strength steels, um, in what you're doing? Yeah, so high
Speaker 2:
11:54
strength steels typically is like the higher carbon content and that kind of thing require much higher preheat temperatures, right? So usually, you know, on the higher strength materials, we're usually at the three, three 50, you know, for pre heat. Now when we get into P 91, so this is primarily in the power market, so that's a [inaudible] Chrome. Um, but the, the difference in P nine for example, in P 91 is the, is the structure, the granular structure of the material. So it's primarily Martin site, [inaudible] P 91. And because of that grain structure it requires, uh, very careful heat treatment. Very careful. So an example, we talked about improper heating. You had mentioned in proper heating, one of the concerns that we have with a P 91 is that the post will heat tree temperature is very close to the lower critical temperature. So the lower critical temperature is where basically the grain structure changes, right?
Speaker 2:
12:54
So we don't want to give get above that lower critical temperature because we want to retain the grain structure that's there, but we were wanting to refine it, right? So and temperate. So two, to do that we have to work in a very narrow zone. So typically interact about 1474 lower critical temperature. And you're usually at 1420 B, you know, 1375 to 14, 24 plus. Well heat treat temperature. So there's not a lot of room between the upper end of the postal history temperature. And the lower critical temperature. Right. So what has happened is, is that, uh, in the early days when they were employing a lot of this P 91, they were running into all kinds of problems because they were the local postal heat treating it. Um, they didn't have a lot of thermal couples on it and they had heat sinks. So for example, I've seen examples where they had a Owlette, you know, uh, an integral, a reinforced a branch connection [inaudible] Owlette right?
Speaker 2:
13:52
That they welded on. And so they were heat treating that weld. And what they did is they put a couple of thermocouples on there on the actual weld for the Olin. Um, so the problem is, is that right above that was the thin wall pipe that welded right to the, all that. And so when the heated it up, they put no thermal couples on there. So what do you think happened to this thin wall pipe that was welling to the OLAP? It got overheated, went over the lower critical temperature. And what code says is says, you know, if, uh, if you go above the lower critical temperature, you have to treat it like P nine, not P 91. All the stress allowables for P 91 are much higher than peanuts. So I'd seen where, um, there's big bulges in the pipe just above the Owlette where the mechanical properties of that material were ruined as a result of overheating. Yeah. And again, I can't stress it enough that heating such a science
Speaker 3:
14:52
and an art form, um, anything you can do to make it easier and understand it better is, is critical to, to success in heating and post-weld heat treat me.
Speaker 2:
15:00
Yeah, absolutely. Absolutely. We spend, we spent a lot of time and code committee just discussing those issues because they're so critical. And you know, we talk about, you know, the slow adoption of a code, two technologies, P 91 was one of those technologies, right. And it presented such a huge advantage to the manufacturers and to the, to the owners to use P 91 because thinner wall, lighter loads on the pipe supports less welding to do and longer life. You know, they could run at higher temperatures, all of those things. There's a real advantage, a real push to do use P 91 over for example, the typical chromes that you would see as a [inaudible], you know, P 22 type stuff. So when they did that though, um, they really, they wanted to, to adopt it but found out about some of these issues and they didn't get the safeguards in there right away. Right. Cause they just didn't know. Right. So it's, it's a, it's a process. The problem was is that it wasn't that the material wasn't good, the material is good. It's just the knowledge of the people handling it had to be increased. Right. Well I think
Speaker 3:
16:12
you think about it, how many hundreds and thousands of miles and hundreds of thousands of miles have been put down of P 91 now versus when it was first put out and how much data we have now versus then and experience, I mean, experience really leads to expertise, right? And, and how we handle it, how we deal with it has evolved as we've learned how to put it into service safely. Yeah. So,
Speaker 2:
16:38
and that's true. And I think every day, I mean appre is, is the electric, it's, it's their research body. Um, so everybody kind of chips into to appre the electric power research Institute is, is the name of it. And, uh, they have done huge amounts of research on, on the welding of P 91 and they've brought a lot of information to the code committee as well as to industry.
Speaker 3:
17:05
This next time is Tim and I talk more about how welders it team and while there's in general, have adapted to these high strength steels, um, and new technology and processes in welding.
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