Seawolf submarine hydrogen cracking

The principal forensic case of the lecture. The Seawolf was supposed to be welded with HY-100 (100 ksi) steel, but high-side chemistry on every alloying element (carbon, manganese, chromium) drove the weld metal strength to 130 ksi with martensitic rather than acicular-ferrite structure. Hydrogen cracking ensued. Repair cost an additional $2 billion, doubling the submarine's price; Congress was unhappy. Only one Seawolf-class was built, partly for this reason and partly because the Cold War ended.

You're not Navy folks, but this summer when the Navy guys have to watch some of these lectures — that's what happened to the Seawolf submarine. The Seawolf was supposed to be welding HY-100, but they had a weld metal that was a little too rich in chemistry. They said high-side chemistry — the carbon was at the maximum of the range, the manganese was the maximum of the range, the chromium, everything was at the maximum of the range, and they were getting 130 ksi weld metal. It was more of a martensitic structure rather than acicular ferrite, and all of a sudden they ran into all kinds of problems with hydrogen cracking. Cost an additional $2 billion for one submarine. Congress was not happy. The submarine was supposed to cost $2 billion, not the repair. So it doubled the price of that sub. I think we only built one Seawolf, or one of the Seawolf class, but that was also because peace had broken out with the former Soviet Union and we didn't need a submarine that would be able to shoot down Soviet submarines.

When the problems are really big you can often go around the attorneys. But when the problems are smaller — say, a hundred-million-dollar problem — the attorneys take control, and then you can't get the engineers together. No one wants to allow their engineering staff to talk to the others. It's pretty dysfunctional as far as solving the problem, because everybody's CYA — who's going to pay for it? When the Seawolf submarine had its two-billion-dollar problems with the welds, they worked it out. What are you going to do? You're going to bankrupt one of the two submarine building facilities? You can't do it.

Tom's full forensic case — he traced the cracking to lubricant contamination in the GMAW weld zone. To repair, Electric Boat used cooling-suited welders ("blue jelly suits") on wheeled carts to work inside egg-crate construction with 400°F preheat. Forced reuse of the heavy plate because four-inch plate was on a >1-year mill backlog.

In fact, the Seawolf submarine had hydrogen cracking. I actually determined it was hydrogen due to a lubricant in the gas metal arc weld zone — not cleaning the lubricants off well enough. That was my conclusion. Electric Boat didn't like hearing that, because they had it left over from a previous job. When they started to repair it, they first had to dig all the welds out and then start re-welding. Congress was not happy at the time with two-billion-dollar problems. They actually started welding in what they call blue jelly suits. The foundations of the submarine are pretty heavy steel, a lot of it in egg-crate construction. You're crawling into some hole, and they wanted you to preheat to 400 degrees Fahrenheit. How would you like to be the welder in egg-crate construction underneath that? They actually put the welders on little wheeled carts, like a mechanic uses underneath a car. They put them in blue jelly suits, pumped chilled liquid through them, they were breathing air through a mask, and they had like ten minutes of welding time before they had to come out and someone else had to go in.