Heat Treatment of Metals ›› 2022, Vol. 47 ›› Issue (7): 156-162.DOI: 10.13251/j.issn.0254-6051.2022.07.028

• PROCESS RESEARCH • Previous Articles     Next Articles

Effect of quenching and tempering process on microstructure and properties of Cr26 hypereutectic high chromium cast iron

Zhang Kai1, Zhang Jianping2, Zhong Ning3, Lu Shangwen1   

  1. 1. Department of Automotive Engineering, Hunan Industry Polytechnic, Changsha Hunan 410036, China;
    2. Sany Heavy Industry Co., Ltd., Changsha Hunan 410199, China;
    3. Institute of Marine Materials Science and Engineering, Shanghai Maritime University, Shanghai 200135, China
  • Received:2022-01-26 Revised:2022-05-09 Online:2022-07-25 Published:2022-08-12

Abstract: Effect of quenching and tempering process on the microstructure, hardness, impact absorbed energy and wear resistance of Cr26 hypereutectic high chromium cast iron was studied by means of XRD, OM, SEM, hardness test, impact test and wear test. The results show that the microstructure of the Cr26 hypereutectic high chromium cast iron quenced at 980-1100 ℃ and tempered at 250-600 ℃ is mainly martensite matrix, M7C3 carbide and a small amount of austenite. The primary carbides are hexagonal, while the eutectic carbides and tempered secondary carbides are short rods. The total carbide content increases slightly with the increase of quenching temperature. With the increase of tempering temperature, the hardness decreases first and then increases, decreasing again when the tempering temperature exceeds 500 ℃, meanwhile, the impact absorbed energy increases first and then decreases, increasing again when the tempering temperature exceeds 350 ℃. For the different quenching temperatures, the tempering temperature corresponding to the maximum wear resistance is different. When quenched at 980 ℃ and 1050 ℃, the maximum wear resistance appears tempered at 250 ℃,while quenched at 1100 ℃,the maximum wear resistance appears tempered at 350 ℃.

Key words: hypereutectic high chromium cast iron, heat treatment, carbide morphology, wear resistance

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