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pISSN : 1598-706X / eISSN : 2288-8381


(논문)연구논문

한국주조공학회지 (19권1호 33-37)

Effects of Heat Treatments on Microstructure , Hardness and Abrasive Wear Resistance in 3%C-10%Cr-5%Mo-5%W White Cast Iron

3%C-10%Cr-5%Mo-5%W 백주철에 있어서 열처리가 현미경조직, 경도 및 내마모성에 미치는 영향

Sung-Kon Yu

Keimyung University

Abstract

White cast iron of 3%C-10%Cr-5%Mo-5%W was casted, and then heat treated with three different methods such as homogenizing, austenitizing and tempering to observe its effects on the microstructure, hardness and abrasive wear resistance. In uni-directional soldification, bamboo tree-like M7C₃ carbide grew along with the heat flow direction, and fishbone-like M6C carbide was dispersed randomly among M7C₃ carbides. While almost pearlitic structures were observed in the as-cast specimen, those of the heat treated specimens consisted of secondary carbide, retained austenite and tempered martensite. In austenitized specimen, the amounts of retained austenite were 60.88% due to the higher cooling rate encountered in forced air cooling. On the other hand, the amounts of retained austenite were reduced from 60.88% to 23.85% in tempered specimen due to the transformation of austenite into tempered martensite. The hardness of tempered specimen showed the highest value, and then decreased in the order of austenitized, as-cast and homogenized specimens. But, the abrasive wear resistance of austenitized specimen was the highest, and then decreased in the order of tempered, as-cast and homogenized specimens.

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