Trolley wire manufacturing by Conform process

Phelps Dodge produced trolley wire by the Conform process (invented at a UK national lab), which knead-deforms powder/rod through a circular cavity to ~1,000% equivalent plastic strain. Output had near-superplastic elongation. British purchasers attempted to reject the wire on a too-much-elongation specification reading — Tom alludes to legal consequences (lost passports).

Remember the trolley wire I sent around? Phelps Dodge made that by something called the Conform process. It was invented over at a National Laboratory in Great Britain. Conform was a great big hydraulic machine — you could throw powder into the machine, and it had a circular die, a circular cavity, and it was sort of like kneading. It would take all those powders, and they get 1,000% equivalent plastic strain. You can put lead through there, you can put aluminum — you're starting to reach the limit with copper. The loads are so high that if you try to put steel through, all you're going to do is crack your steel dies. The steel is not strong enough to deform steel that much. You can deform aluminum because it's soft, you can sort of do copper, you can't do brass very easily — you'll crack your dies, almost no die life. The stuff comes out, and you may have an effective area reduction of 80% from some rod you put in. But the cold-worked redundant deformation could be 99% reduction in area. It's like taking it and kneading that dough over and over in redundant deformation. Very energy intensive process, but you end up with a tremendous amount of stored work, very fine grain size, until that stuff was almost superplastic, which is why it had such good elongation. So much that the British guys who wanted to make an extra two million dollars profit said, oh, you don't make our spec because you had too much elongation, you were too ductile — as if having too much ductility is a bad thing. I don't know that any of them went to jail, but I think they were certainly scared when they lost their passports.

Tom passes a section of trolley wire around the class while explaining the Conform extrusion process. The wire is the artifact; the case is the process. Includes Tom's own failed attempt to use Conform for copper-niobium superconductor wire 30 years earlier (broken dies).

I mentioned Conform before. [Tom passes around a section of trolley wire.] This is a commercial Conform machine. Conform is the way they made this trolley wire. It's an extrusion process developed in the late 60s, early 70s at a British national laboratory — an energy laboratory doing work for the nuclear business. Some guys were doing basic research, and you basically pour some powder into a rotating channel, and at the end of the channel, just by friction, all this powder is being consolidated and churned together. The working end is this big circular thing right here. You've got powder filling in here, this is the motor to run it — a big motor. Conform stands for continuous forming. As long as you pour the powder in, you're mechanically working it, and you're getting tremendous redundancy. If you wanted to figure out some delta for this operation, it'd be like a thousand. You're kneading the powders, cold welding them together, and you end up with a tremendous amount of mechanical work in the alloy.