CPC Subgroup
C21D 1/52 with flames
Full Title
General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering > Methods of heating (C21D1/06 takes precedence) > with flames
C21D 1/52 General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering > Methods of heating (C21D1/06 takes precedence) > with flames