CPC Subgroup
C21D 9/28 for plain shafts
Full Title
Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor > for plain shafts
C21D 9/28 Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor > for plain shafts