Japanese Pcm cracking parameter development

Origin of the Pcm parameter — regression analysis on thousands of steels by Japanese researchers in the 1980s.

However, the second method is hydrogen control, and they don't even use the same carbon equivalent formula. Why? Because this is the type of structural steels the Japanese started developing in the 1980s, and they came up with this Pcm, which is a cracking parameter — P for parameter. Instead of silicon over six and manganese over six, it's silicon over 30 and manganese over 20. They just take thousands of steels, fit them into a regression formula, plot them up, and see which ones crack and which ones don't. And this is what they did, with lots and lots of data and computers to help them analyze it. But it's basically similar to the other carbon equivalent that we had.