Boston Navy Shipyard destroyer boiler pipe weld (stainless-to-chromemoly transition)

Brief reference in the Schaeffler-diagram explanation — Tom invokes this case as the exemplar of dissimilar-metal welding (chromoly to stainless boiler tube on a destroyer, 1978–1979).

If you're welding, this is a Schaeffler diagram. The Schaeffler diagram basically tells you that when you have low chrome, low nickel alloying — for example down here — you've just got a carbon steel, martensite. Over here, a lot of chrome, you'll be very ferritic; a lot of nickel, you'll be austenitic up here — face-centered cubic, body-centered cubic. Here's where 304 sits — garden-variety, a little more richly alloyed — and 310 is very heavily alloyed up here. If you're trying to weld dissimilar materials — I talked about welding the chromoly steel boiler tube to the stainless steel boiler tube for that destroyer back in 1978 or 1979 — when you mix those metals, you're going to hit something in the weld metal that's some combination of the weld electrode and base material in solution. If you're diluted very little, your weld metal composition will be mostly the electrode. If a lot, you'll be down here near the base material. Obviously you can get martensite if you don't do this properly.

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1977. Boston Navy Yard, six weeks into a destroyer dry-dock, at $100K/day, with a weld they couldn't make. Tom (age 27) found in the library that the requested weld would crack within ten years. He proposed an alternative; the foreman doubted it; the dye-penetrant inspection came back clean. Used as the formative consulting-confidence story.

I've had other things which were not a tempest in a teapot. The Navy had a destroyer — they used to have a Navy Yard that repaired destroyers here in Boston — and this was back in 1977 or so. I was a young assistant professor. They called up and said, we've been trying to make this weld, we can't make this weld, the ship has been in dry dock for six weeks and it's going to be late, and every day not in drydock costs about $100,000. So I go out there — well, actually I go to the library first to look at the problem. I'm like 27 or 28 years old, I didn't have any white hair back then. I walk in, I look at the library, and I find, no, you can't do what they want to do. Twenty years ago, people had done studies on this, and it will crack ten years later. This is your boiler — it runs your ship — so no, it looks good for a little while but eventually it's going to fail. So I go out there and I tell them, I can't just say it's okay to do this because it's not. They said, well, how are you going to fix it? I said, well, tell me more about it. So they told me more about it, and I came up with a way that they might not get their cracking. I was all ready to get out of there. I was a little embarrassed because I was a 27-year-old kid and these guys had been working in the shipyard for years. I said, well, I'll see you. I wanted to get out of there because I didn't have any self-confidence about whether this was really going to work. But I just used my scientific principles.