Welding process invention timeline

I did a paper once, a keynote lecture at a welding conference. I looked in the back of the welding handbook — there's a list of 199 different welding and cutting processes. That includes soldering and brazing and plasma cutting and oxy-acetylene cutting, but lots of arc welding processes. They list 199. I looked at how many were developed between 1900 and 1950, and it was seventy-five percent of them. Between 1950 and 1975 it was 24.5 percent of them. And there was one new welding process that had been developed in the previous twenty-five years between 1975 and 2000 when I was given this talk, and that was friction stir.