Study on Composition Design and Heat Treatment Process of Eutectic High Chromium Cast Iron
Author of the article:ZHANG Yewei;YIN Fengshi;DING Zhen;XUE Bing
Author's Workplace：School of Mechanical Engineering,Shandong University of Technology,Zibo 255049,China
Key Words：high chromium cast iron heat treatment wear resistance hardness
Abstract：A kind of eutectic high chromium cast iron was simulated and designed by JMATPRO software,and the effect of heat treatment process on the microstructure,hardness and wear resistance of eutectic high chromium cast iron was studied. The results show that the carbon content in the eutectic interval decreases with the increase of Cr content,and the carbon content in the eutectic interval is 0. 2%. In the composition design of eutectic high chromium cast iron,it is determined that the Cr content is 19% ~ 20%,the corresponding carbon content is 3. 45% ~ 3. 65%,which is eutectic and meets the design conditions of Cr/C ratio in 5 ~ 6. When quenching temperature is 1 000 ℃ and 1 050 ℃,and when tempering temperature is 250 ℃ and 400 ℃,the wear weight loss of eutectic high chromium cast iron does not change obviously. At 400 ~ 500 ℃ tempering will appear secondary hardening phenomenon,hardness increases rapidly,wear weight loss greatly reduced. When the tempering temperature is higher than 500 ℃,the martensite decomposes seriously,the hardness decreases rapidly,and the wear weight loss increases rapidly. The optimal heat treatment process of the experimental material is 1 000 ℃ quenching for 2 h air cooling and 500 ℃tempering for 2 h air cooling,and its structure is mainly tempered martensite,M7C3 carbides,secondary carbides,residual austenite. The Vickers hardness value of the experimental material under the heat treatment process is 843 HV1,and the wear loss is 4. 9 mg.
