Effect of Al on hardenability of 42CrMo bolt steel

doi:10.13251/j.issn.0254-6051.2020.10.032

Abstract

Abstract: Al and Ti elements were added to re-alloy the 42CrMo steel with basic composition. The effect of Al on the hardenability of 42CrMo steel was analyzed by means of end quenching test and section hardness test. The mechanical properties of the new 42CrMo steel were compared by conventional mechanical properties. The results show that the addition of Al and Ti can further improve the hardenability, and the strength of the steel reaches 1200 MPa, and KV₂≥27 J at －40 ℃, which meets the technical requirements at low temperature environment for the wind turbine bolt steel. Through chemical phase analysis test and TTT curves measurement, it is shown that Ti added to steel exerts obvious nitrogen fixation effect. Al is mostly dissolved in steel, making C curves shift to the right, which lowers the critical transformation temperature of austenite and significantly improves the hardenability of steel.

Key words: 42CrMo steel, hardenability, mechanical properties, precipitated phase, TTT curves

CLC Number:

TG142.1

Lü Chaoran, Shi Chao, Jiang Weibin, Liu Jinde, Xu Le, Wang Maoqiu. Effect of Al on hardenability of 42CrMo bolt steel[J]. Heat Treatment of Metals, 2020, 45(10): 164-170.

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