Effect of Laser Quenching on Tensile Properties and Fracture Analysis of 40CrNiMo High Strength Steel

doi:10.3969/j.issn.1000-1093.2014.07.009

Abstract

Abstract: The surface of 40CrNiMo high strength steel is treated with CO₂ laser, the effect of laser quenching on tensile property of the sample is investigated through the tensile comparative test, and the fracture morphologies of 40CrNiMo before and after surface laser quenching are analyzed by scanning electron microscope and energy dispersive spectrometer, respectively. The results show that the yield strength, tensile strength and elongation of 40CrNiMo steel after laser quenching are increased by 25.3%, 24.4% and 7.1%, respectively, while the section shrinkage is decreased by 7.6%. 40CrNiMo steel has obvious yield stage after laser quenching, showing a continuous yield feature. Compared with the primitive sample, the yield strength and tensile strength of 40CrNiMo steel after laser quenching increase, but there are no obvious improvements in the tensile failure mode and the delamination, and the quasi cleavage morphology and low porosity appear at the fracture near the surface of the sample after laser quenching.

Key words: basic disciplines of materials science, laser quenching, 40CrNiMo, tensile property, material fracture, fracture morphology

CLC Number:

KONG De-jun, ZHANG Lei, FU Gui-zhong. Effect of Laser Quenching on Tensile Properties and Fracture Analysis of 40CrNiMo High Strength Steel[J]. Acta Armamentarii, 2014, 35(7): 996-1002.

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