MANUFACTURE OF HIGH STRENGTH AND HIGH TOUGHNESS MEDIUM CARBON STEEL BY DIRECT HARDENING AND TEMPERING

摘要

PURPOSE:To obtain surely a high strength and high toughness medium carbon steel in an energy saving manner by subjecting a medium carbon steel contg. specified amounts of C, P, Si, Mn and sol. Al to direct hardening and tempering under specified conditions. CONSTITUTION:The medium carbon steel contg., by weight, 0.15-0.35% C, =0.020% P, 0.01-0.50% Si, 0.3-(1.75-50XP)% Mn, 0.005-0.1% sol. Al and one or more among =0.1% Cu, =2% Ni, =2% Cr, =1% Mo, =0.1% Nb, =0.2% V, =0.2% Ti, =0.1% Zr and 0.005% B is refined. The steel may further contain =0.2% REM and/or =0.2% Ca. The steel is hot worked, hardened directly at the Ar3 point or above, and tempered at the Ac1 point or above.