Chemical Milling of Alloy Steels

摘要

Experiments were conducted to determine the effect of chemical milling on susceptibility of high strength steels to hydrogen embrittlement and stress corrosion cracking. Alloys studied included H-11, 4340 and 17-7 PH. Results indicated that the acid baths used for chemical milling do initially embrittle these alloys, but recovery of ductility takes place at room temperature within one week if there is no barrier to the escape of hydrogen (such as a plating). A recovery treatment of 48 hours at room temperature followed by 4 hours at 375F is recommended. A high strength steel with a chem-milled surface is more susceptible to stress corrosion cracking than one with a machine ground surface. (Author)