Siaki camshaft laser heat-treatment cracking failure

Sciaky (Chicago, originally French, brought to U.S. ~1940 for gas tungsten arc) built a high-power laser system for automotive camshaft lobe surface hardening. Because laser energy deposits entirely on the surface, the hottest zone was the surface — leading to tensile residual stresses on cooling, surface cracks, spalling. $10M machine was garbage. Switched to electron beam (which deposits ~4 thousandths of an inch subsurface), got compressive surface stresses — the wear-favorable state — and a successful process.

My best example here is actually not a welding issue, it's a heat-treating issue. There's a company in Chicago called Sciaky. Sciaky is a French company originally. There's a Sciaky U.S. in Chicago now. Sciaky came to the United States about 1940 to the Philadelphia Navy Yard. They were just developing gas tungsten arc welding in the world at the time. Sciaky had the best gas tungsten arc welder. The Philadelphia Navy Yard built airplanes out of aluminum, and gas tungsten arc is a great process for welding aluminum. So the Navy brought Sciaky to the United States before the Germans took over everything. Sciaky then set up in the United States.