METHOD OF PRELIMINARY HEAT TREATMENT OF MEDIUM AND LARGE ROLLED SECTIONS Russian patent published in 1995 - IPC

FIELD: metallurgy. SUBSTANCE: method provides production of rods of medium and large rolled pieces from constructional alloyed steels with long period of perlite conversion or without its bilayer structure, consisting of ferrite-perlite low-hardness structure in a surface layer and sorbite with higher hardness in a central layer. That allows to perform subsequent cold working of rods by cutting. In order to realize the method rods of rolled stock of 12 x 12 H4A steel with diameter 90 mm are being rapidly cooled from temperature of period of termination of their hot deformation up to achieving temperature of their surface layer, being lower, than martenite conversion Mc in depth 5-10 mm; then subjecting the rods to isothermic curing at 600-700 C over a time period no more, than three hours. EFFECT: enhanced quality of rolled rods. 1 cl, 1 tbl