sad looking 1903a3

[ssgross]

my copy of hatcher's notebook just finally came in the mail. I skipped right to chapter 9 "Receiver Steels and Heat Treatment". More details can be found in a textbook, but Hatcher gives a nice common sense summary that the reason re-heat treating "burnt" steel doesn't work is it produces very variable and uncontrollable results. There was no process to control adding back in carbon acquired during the initial heat treatment (receivers packed in charcoal and heated, carbon is absorbed), and permanently altered or lost during re-heating (as in the wildfire). This was of course the reason their experiments on re-heat treating the low numbers failed in practice. Some receivers came out fine with re-heat treating, others didn't. Their conclusion was there was no way to practically control the results, and so gave up.