1908 2 June 4/2 With these alloying materials added to steel small gears can be made that, if properly heat-treated, they will be so tough and strong as to make it impossible to break out a tooth even with a sledge-hammer.
1956 3 Mar. 436/2 The specimen [of an alloy] had been heat-treated.
1963 Feb. 17/1 Fifteen different steels..were heat-treated by the National Engineering Laboratory.