Intensive quenching and tempering of 40Cr steel

doi:10.13251/j.issn.0254-6051.2023.02.018

Abstract

Abstract: CaCl₂ aqueous solution was used as quenching medium to carry out intensive quenching process for the 40Cr steel, followed by high temperature tempering. The microstructure, mechanical properties and fracture morphologies were characterized by means of optical microscope, scanning electron microscope, hardness tester, impact and tensile tester, and compared with that of the oil quenching and tempering process. The results show that the fine and uniform tempered martensite can be obtained by intensive quenching with CaCl₂ quenching medium and high temperature tempering compared with oil quenching and tempering process. After intensive quenching and tempering, compared with conventional quenching and tempering process, the hardness is increased by 8%-18%, the strength is increased by 3%-5%, and the impact property is increased by 16%-30%, which can meet the requirements of higher service performance. The optimal quenching and tempering process for the 40Cr steel is austenitizing at 850 ℃ for 20 min, followed by intensive quenching with CaCl₂ quenching medium, and then tempering at 580 ℃ for 120 min plus air cooling.

Key words: : 40Cr steel, CaCl₂ aqueous solution, intensive quenching and tempering, microstructure, mechanical properties

CLC Number:

TG161

Yang Denggui, Zhu Xiaoshuo, Fu Yudong, Alinuer·Maimaiti. Intensive quenching and tempering of 40Cr steel[J]. Heat Treatment of Metals, 2023, 48(2): 117-123.

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