Heat Treatment of Metals ›› 2021, Vol. 46 ›› Issue (11): 64-70.DOI: 10.13251/j.issn.0254-6051.2021.11.010

• PROCESS RESEARCH • Previous Articles     Next Articles

Heat treatment process of Q1100 steel for construction machinery

Liu Hongyuan, Wu Guangliang, Zhang Yongji   

  1. School of Minerals Processing and Bioengineering, Central South University, Changsha Hunan 410083, China
  • Received:2021-05-25 Online:2021-11-25 Published:2021-12-08

Abstract: Effects of reheating quenching temperature (880-980 ℃) and tempering temperature (200-650 ℃) on microstructure and mechanical properties of a high strength construction machinery steel with yield strength of 1100 MPa were studied. The results show that with the increase of reheating quenching temperature from 880 ℃ to 980 ℃, the average austenite grain size of the tested steel increases from 8 μm to 24 μm, the yield strength and tensile strength first increase then decrease and with that at 920 ℃ being the maximum, while the impact absorbed energy at -40 ℃ continues to decrease. When quenched at 920 ℃ and then tempered at 200-650 ℃, with the increase of tempering temperature, the martensite laths of the tested steel are merged, the lath morphology is gradually blurred, and the number and morphology of carbides also change accordingly; and the strengths of the tested steel decrease greatly, while the plasticity and toughness decrease first and then increase. The optimal heat treatment process of the tested steel is: quenching at 920 ℃ and tempering at 200-250 ℃.

Key words: construction machinery steel, quenching, tempering, microstructure, mechanical properties

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