HEAT TREATING METHOD FOR HIGH CHROMIUM WHITE CAST IRON

摘要

PURPOSE:To further raise the hardness of machine parts made of high Cr white cast iron and enhance the wearresistance thereof by subjecting the parts to usual hardening heat treatment, followed by cooling to a temp. below the martensite transformation end point. CONSTITUTION:Wear resistance parts for a rock crushing mill, etc. are made of high Cr white east iron contg. C; 2.4-3.6%, Si1.0%, Mn; 0.5-1.5%, Cr; 14- 28%, Mo3.0%, Ni1.0% and Cu1.2%. The parts are heated to 900-1050 deg.C, held, and air cooled to carry out hardening heat treatment, followed by cooling to a temp. below the martensite transformation end point of the cast iron, e.g. -60 deg.C. Thus, retained austenite in the cast iron is transformed into martensite to further enhance the hardness and wear resistance.