Heat treatment process for wire rods.

摘要

A conveyor moves forward an unconcentrically spiralled loose coil (1a) of steel wire rod (1) having a temperature not lower than Ar3 into a retention bath (4) of molten salt for heat treatment. Just before entering the retention bath, the coil is quenched by spraying a solution of molten salt (8a, 8b) kept at a temperature between 400 and 600 DEG C and not higher than the temperature of the retention bath either from above and below or from only above the coil. Then, the quenched coil is retained in the retention bath of molten salt kept at a temperature between 400 and 600 DEG C, thereby causing pearlite transformation and forming a fine pearlite structure in the wire rod. <IMAGE>