HEAT TREATMENT OF SPHEROIDAL GRAPHITE CAST IRON-MADE PARTS AND SPHEROIDAL GRAPHITE CAST IRON-MADE PARTS

摘要

PROBLEM TO BE SOLVED: To provide a heat treatment method, with which the heat treatment process can be executed in a machining line while avoiding the problems of the strain and machinability of a cast product, and to provide a spheroidal graphite cast iron-made parts improved in the hardness side without lowering the strength side so much. ;SOLUTION: The spheroidal graphite cast iron-made parts are quenched by rapidly cooling after high frequency heating at 1,173-1,323 K, and tempered at 573-823 K for 0.5-2.0 hr. Further, in the parts obtd. by executing the heat treatment to the spheroidal graphite cast iron having the form dispersing the spheroidal graphite in a matrix, the main structure of the matrix is made as martensite and the surroundings of the spheroidal graphite is enclosed with sorbite structure.;COPYRIGHT: (C)2000,JPO