Shop Talk Podcast Episode 3: Revolutionizing Half-Pipe

From the food we eat to the products we rely on daily, the things we use start in an Enerfab vessel. For over a century, our teams have worked on projects that make necessities possible, building the things that make real life work. By introducing new capabilities, innovative processes, and facilities, we can fabricate more efficiently to save our customers time and money and offer you a single-source solution. Over our history, one thing remained paramount — our commitment to fabricating and producing lasting, trusted equipment.

In this third episode of Shop Talk, we discuss all things half-pipe. From jackets and reactors to welding techniques and everything in between.

Read the Full Transcript

Ben Sprengard (Director of Innovation and Modernization):  I personally feel like we are the most forward-thinking company than any other fabricator out there. I work at Enerfab, so I understand that.

But we’re constantly looking, research and development, what’s next? Just like I talked about with the MIG in trying to get the full penetration, well, we are working directly side-by-side with the customer during that process.

And so, you know, I’ll let others talk, but I think it’s that forward-thinking, but it’s also the customer-centric. We are constantly talking to the customer and saying, “Hey, what’s the pain point? What are you seeing out there in your plant? Are there issues?” Because we’re going to solve them. We’re going to be the solution to you.

[Intro Music]

Dan Creech (Executive Vice President, Process Fabrication):  Welcome to our Building Real Life Shop Talk series. Today we have with us Ben Sprengard, Director of Innovation and Modernization, Nick Colvin, Director of Quality Assurance, and Kelly Wyrough, Technical Sales Specialist.

Today we’re going to talk about half-pipe, right? The industry of half-pipe, our experiences with half-pipe, and just in general, right? Just an open discussion about it.

So, Kelly, I’m going to talk to you. You’ve got the most experience in your career in half-pipe. You’ve pretty much been in it since you were 18 years old. So, just what is half-pipe? Just in general, what is it? People may not understand what half-pipe Jacketing is.

Kelly Wyrough (Technical Sales Specialist):  A half-pipe is kind of what it just sounds like. It’s a 180-degree coil that goes around the vessel. It’s for heating and cooling of the products inside of a tank.

The benefits of using a half-pipe versus a conventional jacket or a dimple jacket is, you have to make sure you have really clean water and you’re just cooling or you’re just heating. So, just one. A half-pipe you can do in cyclical service where you’re heating and cooling.

Another advantage of the half-pipe Jacket is you don’t have to use the pressure inside of the half-pipe into your calculation as external pressure. So, you can get the vessel wall thinner, as compared to a conventional jacket where the pressure inside and the vacuum has to go on the outside of the vessel wall, creating a much thicker vessel.

Dan:  So, you’re saying you can use half-pipe and Ben, you’ve got an engineering background, you can use half-pipe from a design perspective to maybe, as external structural stiffening or something like that?

Ben Sprengard (Director of Innovation and Modernization):  Yeah, you can, absolutely. I just got to talk with the customer, make sure they’re okay with that. Sometimes, they have specific requirements that they don’t necessarily want to do that.

Dan:  Yeah, yeah. And then from a half-pipe perspective, does it come in just one size or is there multiple size of half-pipe? I mean, Nick, 2, 3, 4 inch, 6 inch? I mean, what is common in the industry?

Nick Colvin (Director of Quality Assurance):  Yeah, I’d say the most common is 4-inch that we see, but you know, you can do 2, 3, 4, 6 inches. Just depends on the number of dyes and stuff that you want to, you know, use.

Dan:  Yeah. Kelly, you had mentioned earlier there are different types of half-pipe or different types of jacketing. We’re talking specifically today about half-pipe. Maybe elaborate a little bit more, and feel free to jump in as well, on why would a customer choose half-pipe over a conventional method or over what we see a lot in the food and beverage industry, maybe a dimple-jacketed vessel?

Why would they need or why would they choose half-pipe? It seems maybe a little bit more labor-intensive?

Kelly:  It is more labor-intensive, but it’s all in the means of what they’re doing. So, a dimple jacket, say they’re using cooling water, they have high pH value. Well, each dimple is a MIG weld, and so they’ll just pop like pimples under, with high pH. You’ll just crack those wells and they’ll be repairing them and chasing them all around.

On a half-pipe jacket, the wall thickness and consideration is very important in some of the applications for the heat transfer to go through. So, a half-pipe is more efficient to bring the thinner wall down. However, you know, a conventional jacket, to some, they like the flow, they don’t like all the welding. They like to be able to cyclic service really tough on it.

And a higher pressure, maybe they’re just, let’s say, heating instead of heating and cooling. And they’re having a constant, so then a half-pipe would not be optimal. A conventional jacket may be, in that case. But labor-intensive it is, but it has its application where it’s labor-intensive, but a thinner wall. So, it kind of compliments each other on the cost.

Dan:  What are some kind of, maybe, Ben, you elaborate on this, what are some services that are used for half-pipe? What are the most common that we see? Is it for heating? Is it for cooling?

Ben:  Yeah, I’d say really both kind of half and half, but chemical, petrochemical, and it’s really important for that reaction to occur. So, you have, typically have like a catalyst or something inside that reactor. And for that catalyst to really do its thing, having that heat or the cooling, a lot of times it’s the heat to get the catalyst to get the reaction going. But then sometimes once that reaction is going so strongly, it gets really hot, and you need that cooling, that cooling service to kind of bring it down.

Dan:  You said something about the wall thickness of a vessel or something like this. You know, I’ve seen us do a reactor that was four-inch thick that had half-pipe on it, you know. Why would they put half-pipe going through four-inch thick wall? Any idea?

Ben:  I think it’s for that same reason. I mean, even though it’s thick, it eventually will cool down or heat up that process. It just may take a little bit longer for it to get to that point.

Dan:  Talk about some of the installation processes, Nick, as far as half-Pipe goes. And, you’ve got continuous coil, you’ve got the conventional way or the old-school way of doing it. From an inspection standpoint, from a quality standpoint, maybe if you can elaborate a little bit on how we do it versus what other means of installation are in the industry?

Nick:  Yeah, I mean, the optimal way to do it, the way we do it, is taking a coil, a slick coil, and putting it on a machine and rolling it on as wrap by wrap. The reason for that is we eliminate all the butt joints in the half-pipe.

So that helps with less inspection. A lot of the customers that we see, their issues are in those butt joints. So, we eliminate those. So yeah, that’s kind of the way we like to do it.

Ben:  Yeah, I think just something to add to that as well is the alignment of the half-pipe is critical. And one of the main reasons is because of the hotspots that could occur. So, if you have your alignment, maybe it’s supposed to be one inch in between half-pipe. If that goes outside of that range, then you can have some issues.

So, what we do is we actually use, on our burning table we’re able to etch where that’s going to go so we can very clearly identify where the half-pipe gets installed and tack that on. So, I think it’s very important.

Dan:  Yeah, how close can we put, we talk about pitch dimension on half-pipe, but how close can we get that gap or really how close can the industry get that gap and still maintain quality as far as where the half-pipe stops and the welding and the gap in between the next half-pipe? I’ve heard terms- fin effect, in the past. How close can we get that?

Ben:  Yeah, I think that’s an interesting question because, actually, we have a process where we’re able to take the half-pipe and put it fairly close to one another, so much that we’re able to use one weld and actually weld both sides of the half-pipe at the same time, which is pretty neat.

But other than that, it gets into the process that we’re using. So if we’re going to use a MIG process, a GMAW process, then we’re going to want to have that a little bit more spread apart, especially if we’re doing a full penetration weld. We want to make sure we have that correct angle so that we can get in and get a good fillet weld on the ID, which sounds a little crazy. You’re going to get a fillet weld on the ID, but we’re actually able to achieve that where we weld on the outside with a MIG gun, and we can get a fillet weld, quality weld on the ID that we look at with a borescope. So that’s very impressive.

Now, if we have to get in with potentially GTAW, we may have to go a little bit wider so that the welder is able to actually see, he’s getting that keyhole effect, so he’s getting the full penetration when we’re welding that half-pipe. So it kind of varies.

Dan:  So let’s talk about full pen, Nick. You know, I mean, how do we do full pen welding from the fit-up standpoint, welding process, do we gap it? What’s important to maintain the best quality and also ensure that we’re getting that weld on the inside of a full pen half-pipe?

Nick:  Yeah, I think it really depends on the material type. You know, carbon steel, you know, we bevel it to the outside, fit it tight, and we’ll use a pulse MIG process to punch through and get that fillet weld on the inside that you’re talking about, Ben.

You know, stainless, we can do either TIG, GTAW, or pulse MIG to get that full penetration. But anything above stainless, you know, you get into your duplexes, your nickel alloys, your super duplexes, you know, to get full penetration, we’ve seen that you have to use GTAW on that root pass, and then you can cap it out from there, whether it’s flux core arc welding or pulse MIG or even sub-arc, depending on the fillet weld size.

Dan:  And then I presume that we can use a lot more welding processes on fillet weld, right, depending on the size of half-pipe, depending on the material. Kelly, talk to us a little bit from a customer standpoint, right? We’ve been in this industry for a long time, we’ve heard a lot of mixed messages regarding half-pipe, and some customers don’t like it at all.

Talk to us about the differences, what you’ve seen in your career, customer-to-customer, the goods, the not-so-goods, what works, what doesn’t work.

Kelly:  A lot of people don’t like it because they’ve never had a person that could actually, or a company that can actually, give them what they need. It all starts out to- they really don’t know what they’re doing with their half-pipe. They know they’re heating and cooling, but they can’t tell you the exact time, what they’re going from, you know, 500 degrees F down to 150. They can’t tell you that.

So, you have to talk to the process engineers, “What are you doing? What’s the temperature that’s coming in? How hot are you getting? How quick does it have to cool down?” Anything over 250-degree change is recommended to go to the full penetration welds. A big study was done in the early 90s on the thermocycling and when you should really use a full penetration welds, based on failure analysis of failures in different processes. So, the sweet spot is about 250-degree differential.

And of course, the butt welds, you know, in the early days, the half-pipes on the bottom have- were done in octagon shape, like a stop sign, you know, and they had those, they would cut the pipe and butt those joints in an octagon. So, you can just imagine the bottom head is what takes the load of the cooling. They come in through the bottom head, and you have all those stops at that octagon, and it was causing failures in those butt joints.

So, in the early days, it was not like we’re making it today, 180-degree turns in a complete circle. But going from that octagon to the 180 or a little bit over 180 turns, depending on the radius that you’re starting out with, it solved a lot of the problems.

Has it solved at all? No. On the bottom head is much different than the shell. You’re still going to have your butt welds on there, enabled to make that full circle and to go all the way out. But it has stopped. So, a lot of the failures made everybody panic, right? “Why are we using that? Let’s just go with something else.” You know, and some people switched over and went to conventional jackets. But now, their batch time has increased by 25 to 30 percent because of the thickness of the shell that it had to go through.

And they’re like, “Well, the half-pipes, you know, maybe we can live with it.” And then, you know, like Enerfab, we started to research and develop. We find a way of listening to our customers of why they’re failing. Some of our customers have labs with samples of their failures. So, you can go in, and you can see, and you think about it like, “Hey, maybe if, you know, it’s a stainless-steel vessel, but maybe their pH isn’t so great, and they need a little bit more strength.” So, you go in there with a nickel alloy, the filler metal, and onto the stainless to give that the extra strength and the corrosion resistance. Because a lot use steam as well, too. So, condensate sits on the bottom. And if you have high pH and that is going to cause corrosion, and it’s going to be right onto the weld of that.

So, there’s different avenues to help our customers out, and learning from our failures, listening to our customers and understanding how we can make them better — I think that’s what brings us to the top, is because we don’t have to switch it out to Hastelloy. We listen. We have materials engineers like Ben. We have welding engineers like Nick. And we talk to the customers. “Is that all that you have? This is your failure,” and just talk different solutions.

Ben:  Yeah, it’s a great point, Kelly. And when you said condensate, the first thing that came to mind was stress corrosion cracking. And you talked about fatigue, it’s super important to have a full penetration weld when you have fatigue because it allows the flexibility where you don’t have that kind of crevice in between where the fillet weld is, where the crevice is, and it’s constantly going back and forth and they can potentially crack. But that’s one aspect of it.

The other aspect is the fact that you don’t want to have stress corrosion cracking, meaning chlorides can get in there. And as time goes on, you have the chlorides, they’re wet, they’re going through there because they’re part of the water. But as that water evaporates out and then comes back in, evaporates out, you end up getting a higher concentration of chlorides right there in the half-pipe, right there at that weld from the shell to the half-pipe.

So, if you have a full penetration weld, it helps clear out all those chlorides every time you run a cycle. So that’s another big benefit of having a full pen weld.

Dan:  That takes me to a job we did, if I remember. We did some testing to try and achieve a full pen weld because the customer was concerned about product getting underneath the half-pipe where there was a fillet weld.

So we didn’t go with a full, full penetration weld, but we had to at least penetrate that to minimize down, I think, some of that.

Ben:  Yeah, exactly. I know exactly what you’re talking about. And in that specific instance, we can achieve full pen weld if the customer needs that. However, in that specific instance, they didn’t necessarily need it completely. So, what we did, we actually beveled to the ID of the half-pipe on that one, and we achieved what they needed. That was actually solid duplex.

Dan:  I want to key in on something you talked about earlier. You were comparing half-pipe, or you were comparing half-pipe jacketing to conventional, I think, because they can both take aggressive, more cyclic service-type stuff.

Why would a customer go to half-pipe versus conventional? I mean, talk about, I’m asking the question, I think I know the answer, but talk about the difference in fabrication costs, fabrication time, and why, and other benefits of why a customer would go half-pipe versus conventional.

Kelly:  Well, let’s talk about that because it depends, right? And material of construction is your biggest thing. If it’s a solid nickel alloy, then going to a half-pipe will be cost-effective because it’s going to bring that wall thickness down. You’re not putting 150 or 200 psi, plus the full vacuum that half-pipe usually goes under, on the outside of that. So, your vessel wall is going to get thinner in that case. So, a half-pipe will be more attractive when it comes to cost. Their batch time will be quicker.

Now, if it’s a clad reactor, it doesn’t really matter because the carbon steel is going to be better heat transfer mechanism than the alloy in the inside for the most case. So, and the cost-effectiveness of that, you know, $1.50 a pound for carbon steel versus the noble alloy on the inside and a conventional jacket. There’s also a fine line, right? So, if you have a high internal pressure, that’s going to govern over the half-pipe going out. So, a conventional jacket would be a good application for it, it’s less. It’s not going to increase your wall thickness if your ID pressure inside that vessel is a lot more.

And that’s what’s governing. So, you have to really weigh on, what’s the material of construction, what’s the design pressure, and how is that going affect it, and what’s more cost-effective? And in some cases, it’s going to be a half-pipe. And it’s going to save hundreds of thousands of dollars on a 10-foot diameter, you know, nickel alloy vessel versus a carbon steel clad.

Dan:  I think the biggest misnomer, and it’s just maybe a cosmetic thing, right? Customers look at a conventional jacket and just think it’s a shell over a shell, versus half-pipe looks so much more complex. I mean, in reality, if you, you know, you talk more about it, I mean, we’ve seen, we’ve worn the hat how many times — half-pipe is actually pretty easy to put on and pretty efficient.

So, Nick, I want to ask you a question about about common challenges during welding half-pipe, right? I mean, you talked earlier about GMAW, GTAW, fillet weld versus full pen weld, you know, from an inspection standpoint, from a QA standpoint, why don’t you talk about some of the some of the things that you see the challenges around welding and what you see from an NDE perspective and how do we train the industry and train our people to overcome those?

Nick:  Yeah, I think the biggest challenge is when it’s continuous, you know, once you get so far around, you can’t really look at the inside of it unless you, you know, cut ports in the half-pipe and that kind of, a lot of times, defeats the purpose of having, you know, no butt joints.

So, we do have borescopes and stuff that we utilize the, you know, check, you know, so far into the half-pipe, but, you know, obviously externally, you can do some other tests, PT being one, you know, MT if it’s carbon steel. But, you know, that’s I mean that’s some of the ways you can inspect inside, and out, of pipe welding.

Dan:  We’ve seen customers ask for 100% inspection on half-pipe. So I’m going to, it’s kind of a quite…how do you do that with an efficient fit up process of going from slit coil, right? So, you’re rolling slit coil on to a vessel, and you can fit it up and tack it. Can you give 100% inspection that way? How do you do it if the borescope only goes so far around in a vessel?

Nick:  Yeah, I think it’s like, like I said, you know, you have to cut inspection ports into it. I mean, there’s really no, no other way to do it, other than that. And that’s what we’ve seen from customers, you know, that 100% borescope inspection and, you know, verifying that that fillet weld it is, is, you know, in fact on the ID the half-pipe.

Dan:  Now, Ben, I know you’ve done some further research, investigation, testing, analysis on half-pipe, specifically full penetration half-pipe and how, depending on, I think you mentioned earlier, the pitch of your welding and how you come into the shell. And I remember one project, there was penetration into the parent metal from full penetration welding. Maybe just elaborate a little bit about some of the analysis that we’ve done to make ourselves better, to educate the industry more.

Ben:  Yeah. So, at Enerfab, we’re constantly researching, developing, “how do we get better, how do we make it more efficient, how do we keep the quality but also give a better price to the customer?” And that’s exactly what we were doing. We are, we’re like, “Right, we’re going to go crazy and see what can happen.” You know, people say, “Alright, this is a quarter-inch thick half-pipe. There’s no chance you can get full pen weld with just Mig.” And we’re like, “Well, maybe we can.” So, we just go and we blast the metal at it and see if we can and- but we need to verify that it actually meets the quality requirements.

So, what we do is we scan the ID bore, or the ID of the vessel itself, and that will scan the weld that’s penetrating into, not only the half-pipe, but also the shell as well to verify we don’t have any kind of defects flaws that are kind of penetrating into that into the shell. So, we’ve been able to…The benefit of the NDT is we can verify if there’s an issue or if there’s not. So once there’s an issue, back off a little bit to verify that we’re still making the full penetration, but verify also that we don’t have those defects in the natural shell itself.

Dan:  Let’s talk about materials — materials around half-pipe. Over the years, it’s either same metal as shell, different metal as shell, different material combinations. What’s the most commonly used material? Nick, what’s the most common material you see in half-pipe?

Nick:  Seems like it’s carbon steel or, you know, straight grade stainless 304 or 316 is, you know.

Dan:  No matter what we’re putting it on?

Nick:  Well, you know, if it’s a high alloy vessel, you know, the shell the heads are, say, a nickel alloy. Typically, that’s a stainless steel half-pipe we’re putting on the vessel for cost-effectiveness of material, you know, it’s not seeing the product inside the vessel that’s maybe highly corrosive. So, it’s seeing cooling water, oil, steam, whatever the, you know, cooling or heating element is. It doesn’t necessarily have to be that high-nickel alloy material for the half-pipe.

Dan:  When you’re welding dissimilar metals…You guys are both welding engineers, when you’re welding dissimilar metals, what, what, what weld wire do you choose? So if you go, say, stainless steel half-pipe onto a nickel alloy vessel. What weld wire do you need to use with the half-pipe?

Nick:  Yeah, you’re going to use the nickel alloy, you know, that’s with the- that goes with the nickel alloy, you know, it’s…If you’re welding C276 and you’re putting a stainless steel half-pipe on it, you’re going to use nickel chromoly 4, you know, so it’s going to match the, you know, higher nickel alloy material.

Ben:  And there’s always some exceptions. For example, you have, say it’s a C276 vessel, and you have 2205 half-pipe, which we’ve had before. And there’s a lot of fabricators out there and folks that say, “Alright well, I’m just going to use the nickel chromoly 4 or maybe the nickel chromoly 3.” Nickel chromoly 3, a lot of people use that for dissimilar welding. And I call, that’s the workhorse alloy, I’m just going to do that- I know it’s, I know it’s more corrosion resistant than the duplex. All is good.

Well, the problem is, it’s the niobium that’s in nickel chromoly 4, which is the equivalent of Incanel 625. And that niobium will react with the high nitrogen in the duplex and formed niobium nitrides. Well those niobium nitrides, they will embrittle that material.

So we talk about we talk about the fatigue, well that fatigue does not like the brittle material, so that can be a big issue. So, you need to make sure that if you’re going to weld, say C276 to 2205 or 2507, that you use a filler metal like C22. So, something like that, nickel chromoly 10, that does not have that niobium in it. That’s just one example.

Dan:  We’ve talked about half-pipe, I think we’ve covered a lot of generalities around half-pipe and probably more focused on the shell, right? Let’s talk about half-pipe on the head. You know, we can automate a lot of shell half-pipe welding, but let’s talk about what talk about the head, right, and the different shapes of the head and how we put half-pipe on heads.

Why hasn’t, why haven’t we been able to find a technology to automate half-pipe fit-up on heads? And what, what’s the challenges of head fabrication, Nick?

Nick:  Yeah, I mean, really the biggest challenge is they’re, the tolerance of a head is just so, it’s so vast. You know, the dish radius, the knuckle radius, can be different dimensions so, it’s not like… When you order ahead, you know, you know what dimension you’re going to get. It’s, you know, it’s ever-changing, that’s another big issue with heads is it’s ever-changing (the knuckle radius) and it’s not, you know, it’s not like a shell where it’s round, it’s easy to, you know, automate and roll so…

Dan:  What about different shapes? Like let’s talk about going down the shell, around the knuckle, right, of a pressure vessel head. You know, I’ve seen a lot of reactors in the past, we’ve done a few that have gone around the knuckle, around that complex shape. What’s the message to customers, Kelly, I mean that may not think you can put because they… We see drawings all the time, it’s half-pipe on the shell, and it’s half-pipe on the head, and there’s always a spot — whether it’s, they didn’t think half pipe could be put there, whether they put their, their legs or their skirt there, or something. Can you talk a little bit about why you would take and put half-pipe and maybe different situations where it’s really important to have half-pipe continuous all the way down the shell, around the knuckle, over the weld seam, and, and continue out all the way down to the bottom head?

Kelly:  A lot of these half-pipe reactors that we build are used in batch reactors, so they might just be filled up the bottom head and partially up the sidewall. Without that, they’re not getting any volume, they’re missing that whole area of heat transfer. So there are areas that we can fill, like Nick said about the head itself, the geometry is hard, the knuckle radius is really hard.

Not you know, it’s not, you know, not any fabricator you should choose to go around the knuckle. A knuckle is very hard, that’s going to be a very high-stress area, knowing how to put it on, how to fit it up — it’s not as simple as a shell. You know, a shell is round, it’s going, you know… You have two sides that are equal. In a half-pipe on a knuckle, it’s not equal, you have two different legs.

So the way that you fit it up, the way that you cut the half-pipe in order to fit it up and keep the gap is very important, or they will have failures. So it’s a challenge, they don’t think it can happen because of that area. You’re going from a straight, you know, part of the head, going down to the dish, and it’s very, very hard to do. So, choosing how you cut that, maybe you have a longer leg on the one side than you have on the other side, to make sure that you have a consistent gap in everything. It takes a lot more time, it’s not just cut a half-pipe and get it going on that bottom head.

Dan:  Yeah, no, that’s interesting. I’ve seen it, I’ve seen it on some of the stuff we’ve done, and I heard it’s the most critical heat transfer area of a reactor is that knuckle area, where, I think, where the agitator typically is bottomed out, right?

Kelly:  Yeah.

Dan:  That’s interesting.

So, I want to ask, we’re going to get into future here in a little bit, but I want to talk about different sizes of half-pipe, right? So, I know the most common that we’ve used in the past, you know, from our estimating standards or what we think is the most efficient way. But I’ve seen three, I’ve seen four, probably the most common are those two sizes. I’ve seen us do five-inch. But Kelly, in your prior career, you brought to us six-inch half-pipe, or what I’ve heard some people say is a 130-degree.

I guess, and group here chime in, what’s the advantages of six-inch? What’s the advantage of three-inch? When, when is it right for a customer to pick what?

Kelly:  So, I know that the standard half-pipe in the industry that we see coming from the customer is a three-inch half-pipe. That’s a lot of welding on a ten-foot vessel and up, you know. So, going from a three-inch too a six-inch on ten-foot diameter and up, you can increase the heat transfer area about 15 to 20% by going to six-inch, 130-degree half-pipe, rather than the standard three-inch, and you would cut down the welding about 15%, and your cost goes down —more heat transfer, less cost, right, and less problem areas because you have less turns, but you’re increasing your heat transfer.

The reason that the six-inch is 130 degrees pressure drop concern and pumps — usually when the customer goes up and we offer it as an option, they don’t have to change their pumps out. They’re not putting- it’s not a big pressure drop. Sometimes they might have to change their fan blade out, a different style of a fan blade, but not the pump. So that’s the reason why it’s 130 degrees versus 180, due to the size and how it has to move.

Dan:  Why would a customer choose three-inch half-pipe?

Kelly:  It’s what they know, it’s a standard. It’s funny because when, when they start a new process out, they have what’s called bench style, little, tiny reactors, you know, and then you got to scale up, you know, when they’re scaling up, sometimes they’re very large versus maybe a 36-inch vessel with a three-inch half-pipe on it. And they’re going, going up there like, “Wow,” and all that welding and all that.

So, we offer it as an option to increase their heat transfer area of the… Have better batches, come out a lot shorter cycles, right? And they don’t know, so it’s kind of educating the customer, you know, giving value at it.

Dan:  Let’s talk about technology, right, around half-pipe future technology. What are some of the things that we’ve seen in the industry? What are some of the things that we’re doing from a half-pipe optimizing fabrication process, if you will, Ben, Nick, in the shop?

Ben:  Yeah. So, I’d say that the latest technology we have right now is, we’re able to weld on both sides of the half-pipe at the same time. We have a system out there. It’s got two independent team trackers, it’s got a leading and lagging camera system on there, and it’s all pulse MIG. For the most part, it’s fully automated. We do stuff with a joystick where the operator can change that, if necessary, if you see some kind of an anomaly in the half-pipe. But what I think, the most important thing moving forward is all the vision tracking, it is just completely different than it’s ever been in the past. Where you can track, you could scan, take a cross-section of when you’re welding in between two half-pipes and keep the arc to the left or the right or however that may be, and take advantage of welding with robotics. So, you know, we’re looking at that as well. I’d say those are the two biggest things that are out there.

Nick:  Yeah, like real, I mean, you’re talking about real-time, like laser tracking, right?

Dan: Real-time laser tracking. Maybe elaborate on that a little bit.

Ben:  Yeah, you can take that or I can, either way.

 So, there’s several companies out there we know of, Servo Robot and a couple others. But so, basically the way that works is, it’s basically, has a laser scanning the cross-section of the half-pipe. I’m kind of talking to half-pipe, it goes down the back up, and it’s going and it’s riding right in front of the welding torch as it sees maybe a half-pipe goes in and then out. It’ll follow that, and there’s no person involved at all. It’s just completely being done by the laser tracker.

Dan:  Is that like newer technology to the same tracking systems that we have? Right?

Ben:  We actually have some of these. But the pricing’s coming down, the ability to connect those two more hard automations is much more easy and fluid. The dashboards are much more easy and fluid. So, I think that’s why it’s beneficial. It’s beneficial to the industry, honestly, that, you know, people are able to use this, and I think it’s great for everyone.

Dan:  How long has half-pipe been around?

Kelly:  Oh, goodness. That’s been around a lot longer than a lot of the people sitting right here. I mean, the first, the first…

Dan:  You talked about octagonal, right? I guess it was considered half-pipe back then.

Kelly:  So, if you look at the patents that are out there, you know, they date back to the early 1900s in half-pipe. So, it’s been around a long time. And it’s been improved over the years. You know, you see newcomers come in saying, “Oh, I got this, and I got that,” and you look at it and you’re like, “That’s old technology, we’ve seen that before.”

I was fortunate enough to meet one of the early patents, Bernie Veal, when I started, and just to listen to him, of his trials and tribulations, he even created the machine that takes it from coil, you know, and patented that as well, too. And some people are still using it today. And then you come into Enerfab’s shop and see what we have done since that early 1900s, you know, it’s just, it’s incredible to see the changes. It’s ever-changing.

Enerfab does a good job. They’re trying to stay ahead of technology, you know, or keep up with it the best that we can, and every, every time, we’re fortunate that our ownership allows us to research and develop and how to get better. And our customers are good too because they let us know of their failures. And we try to understand what, in fabrication, could improve it. Yeah, so, but it’s been around a long time.

Ben:  Yeah, I think also just from a technology standpoint — one, I was talking about how we kind of apply the welding and the angles and things like that, robotics, but also it’s the manufacturers of the welding supply and welding power sources. It’s amazing, the welding power sources these days are completely different, they’re synergic lines.

So we can modify- so pulse MIG, so you look at pulse MIG, you kind of have the arcs going up and down, not just the arc but the amperage is going up and down, up and down. Well, you can modify that curve so that you can potentially even increase your penetration while decreasing heat input, which is fantastic, especially when you look at the duplex stainless steels and nickel-based alloys.

Dan:  Can you use sub-merge arc-welding on half-pipe?

Ben:  Oh yeah, you can do it. Yeah. So, typically, cat pass.

Dan:  I’ve seen us, and I know that we probably won’t publish this because this is proprietary, but we’ll talk about it anyway, I’ve seen us do some unique things with the vessels themselves to put it in position so that we can optimize welding or let me say, we can make the welding process even more efficient. And Ben, you know what I’m talking about.

Ben:  I do, and I can go into that. One of the legends, Paul Brown, I believe, is who you’re referring to. The one who kind of came up with that, and it was basically taking a vessel and putting it in a diagonal position so you’re welding in the flat, which is pretty darn good, a good idea.

And so you can- I talked about putting the metal to it, that’s putting metal to it. You can put sub-arc down, especially if you have a thicker wall shaft pipe that can accommodate that kind of heat input. But you can go very fast, as you increase your travel speed, you decrease your heat input so you can go quickly, especially with carbon steel, and you can knock out vessels fairly quickly.

Dan:  Let me ask the question. Let’s talk about some concerns around- every welding process may, may be right or wrong for the application. I mean, I would think that sub-arc, and flux core, and full pen wouldn’t be a viable welding process on your full pen, right, because the flux.

Ben:  Yeah, there’s a couple different reasons. One is it’s, it’s super important that you don’t blow through or have any kind of an issue where you’re putting too much weld metal down. One, because of the half-pipe, it just can’t support that much weld, that much heat input, but then also the ID of the vessel, the ID of the vessel could potentially be overheated. So that’s the last thing you want, you may think, “Alright, this is a carbon steel vessel on the outside, it’s clad, but we’re on the carbon steel side.” Well, that carbon steel side is, although it’s on the outside, the alloy on the inside will be affected by the heat input going on the outside of the vessel, so we just need to be cognizant of that.

Maybe you won’t see it this year, maybe even 10 years, but maybe 12 years down the road, it potentially could have become sensitized a bit where some of the chrome or the moly starts to react with the carbon and form these carbides. It takes that chrome and moly out of solution, so when you think you may have had like an 18% chrome material on the ID of the vessel, it might actually be like a 12 or a 15 because it’s tied up in those carbides. So, you need to be very aware of what’s happening on the ID of the vessel when you’re putting so much heat input, potentially, on the outside.

Dan:  So let me ask you a question. Okay, from an NDE perspective and what you’re seeing also from what we’re doing on the shop — what’s the most critical part of achieving the highest quality possible on half-pipe? The whole process, what’s the most critical part?

Nick:  I would say if you’re automating, fit-up is everything, right? If you have a bad fit-up, you know, you’re not going to be able to automate that welding at all. Now there’s some variations with that if you’re going to do it by hand, you know, whether it’s a GTAW, GMAW, you can have some mismatch and stuff like that, but the way we typically do it is we’ll fit it tight.

So, you know, all the way around, but fit up, definitely from an automation standpoint, is number one. I mean, you have to have good fit-up.

Kelly:  What do you do when, no, not every vessel is round, you have flat spots? Do you re-roll it?

Nick:  Yeah, so we will, we’ll re-roll shells before we start putting half-pipe on. We’ll make sure they’re, you know, 100% round. Obviously, nothing’s perfect in our industry, right, but yeah, we’re going to definitely re-roll after welding those vertical seams and round seams before we start putting half-pipe on.

Ben:  Yeah, Nick, I was just going to say, you’re exactly right on the fit-up. One other benefit is just making sure that we have, or an important aspect is, that we have the right bevel. Because if you don’t have the correct bevel, and say you need to have it fairly sharp so you have a sharp edge there, so you can very easily get your keyhole and your welding. If you don’t have that, you’re gonna have a lack of penetration. So having consistent bevel is important as well.

Nick:  Yeah, when it comes to full penetration right, you know, you have- the bevels got to be right and it’s got to be, you know, to be able to achieve that keyhole.

Kelly:  You know, a lot of these vessels are thin wall, thinner wall. So heat input — what do we do on the ID of the vessel to ensure that we get the heat tint removed and make sure that we’re not overheating the vessel and sensitizing it like you said?

Ben:  Yeah, that’s a great point, Kelly, and so if we’re doing half- if we’re doing sub-arc, we’re going to make sure that that vessel wall is not too thin and where it could potentially have an issue, have an influence on the integrity of the ID of the vessel.

Now, sometimes the vessels are just super thin and at that point, even a TIG weld, even like a low heat input TIG weld, you could have an issue, so what we’ll do is we’ll make sure we remove that heat input, or the heat tint, sorry. And we can do that either mechanically or with an acid, so we can do either process. All customers are a little different, so they may have preferences, but we can do either one.

Kelly:  Right, and we look at that at the time of quote as well too. There’s some vessels that will be, a wall thickness only needs to be three-sixteenths of an inch thick, but we will not go below a quarter of an inch due to washboarding. I see it time and time again, a customer is like, “Your wall’s heavier than somebody else’s,” and we’re like, “Well, did you ever make a tin foil ball?” I, and then I, you know, the good old glue on a piece of paper to show them I’ve used that on a- many years. They’re like, “Well, what do you mean by a washboard effect? You put some glue down on a piece of paper, let it dry, and it crinkles in.”

I said, “That’s the same thing with metal,” I said, “The more weld you put on it, it’s going to look like that piece of paper.” So, we like to do a quarter of an inch. I know when I first started at Enerfab, we wanted to do three-eighths, you know, as our minimum, to ensure that. So, we’re always thinking about the integrity, and you have to think about the integrity, but you also have to tell the customer, “We can do a three-sixteenths wall, but you’re going to have some hold-up points in your product depending on what you have on the inside due to washboarding.”

Dan:  Right, and we talk about this all the time as far as when customers specify half-pipe, and I know, Kelly, you’re a stickler for this, right? What are we doing on the ID of the vessel to remove discoloration, right? Because people attribute discoloration to heat affected zone, and to other things like this, so I think it’s really important to get the message out to our customers that if they’re, if they’re asking for half-pipe, that they start specifying what to do with the discoloration on the inside because you can’t avoid it on something, you know.

So in a competitive bid situation, we’ll bring it to the customer’s attention and add a clarification in there to say that, to remove heat tint discoloration on the inside, you know, add this, whatever it may be or “Hey we’ve removed it,” but the message to the customer is, it’s a real thing, it’s a real cost, it’s labor, right?

So just two final questions. I want to bring this up because I want to make, I want to make it aware to the industry, but I also want to talk to the industry about putting carbon steel jacket on nickel alloy, right? And so, Kelly, you raise your eyes on this and, from a customer standpoint…

Kelly: We’re building one right now!

Dan:  We’re building one right now. But talk about why, right? I think it’s really important for the industry and for customers to understand, because their big concern is cross-contamination, and corrosion from the rust of carbon steel and…

 So all of you can chime in on this: from a customer standpoint, Kelly, what’s the message to the customer?

Kelly:  You know, we went to the customer on this one that we’re building now, 13-foot diameter, Hastelloy reactor with carbon steel half-pipe, and they’re swapping out- it was a carbon steel vessel with carbon steel half-pipe. They had no issues with their carbon steel, so they do not want to change it out.

You know, one point of argument you think about it, you know, the carbon steel has the same thermal expansion as the C276 so there’s no argument there. But the cross-contamination, it’s kind of funny, you know, they have, every repad on every nozzle is Hastelloy, because they didn’t want contamination. But we have a carbon steel half-pipe going on. So, we talked to them, we sat down with them, we talked about using duplex to go with it because they were afraid of their pH and their water. But they decided, “No, we’ve had carbon steel, and it’s not failed us.” So, they wanted to keep it. So, it’s a discussion.

 A lot of the chemical plants might not have a materials engineer. So, they’re going back, they don’t want to change. They know that they did, they had corrosion on the inside, they knew they were having a more aggressive product on the ID of their vessel. So, they got outside sourcing to tell them to go with the Hastelloy, but they never mentioned the half-pipe to their materials engineer that they went out to. So, here we are today, building a Hastelloy reactor with carbon steel half-pipe.

Ben:  So, so whenever you have a very noble alloy, C276, nickel 200, whatever it may be, and then you put a small amount of carbon steel on it, well, then that galvanic cell is even bigger. So now that corrosion resistance of the carbon, it’s like nothing. So, it’ll just get eaten away very quickly because you have that entire big, noble hunk of metal that it’s touching now. So, it creates a very big galvanic cell that you typically don’t want. So that would be my biggest reason I wouldn’t want that on there.

Dan:  Yeah, I just think it’s you know, we’ve done it, you know customers, I think it’s not a misnomer, but I think in the industry, people just automatically assume, “Why would you put carbon on there?” Right? There’s a huge cost savings opportunity there to the customer.

I mean, and also, you know, from a heat expansion, I think you brought up a heat expansion, right? Nickel and carbon are more closely related than a stainless or a duplex, and a nickel. So, I just wanted to get that out there because I thought it’s pretty interesting.

Last question, we’ll wrap it up. And I think all three of us, or all four of us, can probably go on and on about this. So, let’s just keep it simple. Why Enerfab? Why Enerfab for their half-pipe needs? You know, we’ve talked about this, you know, I lead business development and strategy for the company, and I’ve always said that if we can fill up our shop with nothing but half-pipe reactors, that’s what we want to do. We love doing it. But to the customer, why Enerfab?

Ben:  I personally feel like we are the most forward-thinking company than any other fabricator out there. I work at Enerfab, so I understand that.

But we’re constantly looking, research and development, what’s next? Just like I talked about with the MIG in trying to get the full penetration, well, we are working directly side-by-side with the customer during that process.

And so, you know, I’ll let others talk, but I think it’s that forward-thinking, but it’s also the customer-centric. We are constantly talking to the customer and saying, “Hey, what’s the pain point? What are you seeing out there in your plant? Are there issues?” Because we’re going to solve them. We’re going to be the solution to you.

Dan:  No, I appreciate that. Nick, I mean, you see…

Nick:  Process solutions, I mean, that’s literally what we do, you know, we’re talking with the customer all the time, you know, if they want, if they want something or seeing something, we’re going to figure out a way to, you know, make it happen and, you know, change our process or develop a new process. I mean, how many different welding processes with half-pipe have we developed directly with customers? I mean, I can think of five, six in my head right now, like right off the bat. So that’s kind of, you know, that’s, that’s why Enerfab, in my opinion.

Dan:  Kelly, I think you’d have the most experience on this because you’ve, you’ve come from different philosophies, right? Different fabricators in the past, you have the most customer interaction. Why Enerfab?

Kelly:  Well, I would say our research and development dollars that our ownership puts into us. We’re talking six figures into bettering ourselves in the area of half-pipe. And that’s not just one time, that’s a yearly. We’re always on top of technology as well as our customers. We have a great relationship with them, when we hear of a failure of something on in their plant, our ears pop up, and it’s a half-pipe, and they share their analysis with us. We work hand in hand with them to solve it. You know, we, we belong to Materials Technology Institute, where we’re always trying to better, how can we fabricate something better to meet this application? And every half-pipe application has its similarities. They’re, they want to get the most out of it, they want to heat it, they want to cool it. They have water hammering, which rocks the whole plant at times. How, how do we make it so that they don’t have these failures, they don’t have downtime? And that’s the research and development that we put in at our cost. It’s every year we’re putting something in, we do something new. I see us roll a shell, and put that half-pipe on, test our procedures out before we start on production. That’s research and development dollars. And that’s a lot, that’s a lot of money for that customer to have reliability on their piece of equipment, and it shows in our equipment.

Ben:  I remember projects where we’re actually taking notes on exactly the frequency, and the processes, and parameters from the customer. They were like, “We really need to figure this out.” So we got all these parameters, got with, with the Edison Welding Institute right up there in Columbus, worked with them. And we developed a process to actually repair some of these, they were, they were dimple jackets, actually, but, yeah, so I mean, that’s just an example of getting so much in the business and being a solution to the customer.

Dan:  Thank you for joining us on our Building for Real Life Shop Talk series. We’ll see you on the next episode.

[Outro Music]