Original Article

Effect of quenching temperature on microstructure and properties of multivariate high chromium cast iron

¹ College of Electromechanical Engineering, Xi’an Polytechnic University, Xi’an 710600, Shaanxi Province, PR China
² College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, PR China
³ Zaozhuang Guangyan Industrial Technology Co., Ltd., Zaozhuang 277099, Shandong Province, PR China

^* e-mail: hgfu@bjut.edu.cn

Received: 1 June 2024
Accepted: 13 August 2024

Abstract

The effects of different quenching temperatures on the microstructure and properties of 3.3C-20.0Cr-1.0W-0.5B-2.0V-1.8Mo (wt.%) high-chromium cast iron were investigated using an optical microscope, scanning electron microscope, X-ray diffractometer, Rockwell hardness tester, microhardness tester, and wear testing machine. The results show that the microstructure of as-cast multivariate high chromium cast iron mainly consists of eutectic carbides (M₇C₃), austenite and martensite matrix. In the process of quenching temperature increasing from 950 °C to 1150 °C, the morphology of massive eutectic carbide (M₇C₃) did not change. Acicular eutectic carbide (M₇C₃) appeared to aggregate and grow, and was distributed in the form of blocks or rods. Secondary carbides (M₂₃C₆) were precipitated in the matrix. The matrix is transformed from austenite to martensite, with a small amount of residual austenite. The hardness and wear resistance firstly increased and then decreased. The hardness of the 1100 °C × 1 h + fog-cooled high-chromium cast iron reaches a peak of 67.0 HRC, and the abrasion resistance increases by 37.0% compared with that of the 950 °C × 1 h + fog-cooled specimen.