Patent ID: 6294031
Filing Date: 2001-09-25
Classification: C21D

Abstract:
A method of producing a heat-treated steel member selected from any one of a shoe, a bushing, a link, and a pin used for an endless track mounted to a construction vehicle, and a cutting edge of a blade used for a construction vehicle and a vehicle with a snow plow, said method comprising:providing a steel member of low-carbon boron steel containing about 0.20-0.30% carbon by weight;shaping said steel material to form a shaped material; andquench-hardening said shaped material to form a low-carbon martensite microstructure close to a surface of said shaped material with a hardness of HRC 45 to 49, a tensile strength of 144 to 155 Kg/mm.sup.2, and a toughness of 7 to 10 Kg.multidot.m/cm.sup.2 Charpy impact value;said quench-hardening including heating an entire thickness of said shaped material to above an Ac.sub.3 transformation temperature and then rapidly cooling said heated shaped material to below about 200.degree. C. without tempering said shaped material subsequent to said quench-hardening.