回火温度对40CrNi2Mo钢力学性能和干摩擦性能的影响

对40CrNi2Mo钢进行200~575℃回火处理,采用X射线衍射仪(XRD)、扫描电镜(SEM)、激光共聚焦扫描显微镜、维氏硬度计、万能试验机和磨损试验机等研究了回火处理后40CrNi2Mo钢微观组织演化对其力学性能和干摩擦性能的影响。结果表明:随着回火温度的升高,40CrNi2Mo钢板条马氏体中固溶的过饱和C原子逐渐析出,微观组织逐渐向粗大的铁素体、球化渗碳体和粗化的碳化物转变;压缩屈服强度、弯曲强度和硬度降低;325℃和425℃回火处理后析出层状渗碳体导致40CrNi2Mo钢的加工硬化能力和冲击韧性先下降后升高;硬度降低导致耐磨性降低,磨损机制由磨粒磨损逐渐向氧化剥层磨损转变。

Effect of tempering temperature on mechanical properties and dry friction properties of 40CrNi2Mo steel

40 CrNi2 Mo steel was tempered at 200-575 ℃. The effects of microstructure evolution on mechanical and dry friction properties of the tempered 40 CrNi2 Mo steel were studied by means of X-ray diffractometer(XRD), scanning electron microscopy(SEM), laser confocal scanning microscopy, Vickers hardness tester, universal testing machine and wear tester. The results show that with the increase of tempering temperature, the supersaturated C atoms in the lath martensite of the 40 CrNi2 Mo steel gradually precipitate, the microstructure gradually changes to coarse ferrite, spheroidized cementite and coarsened carbide, and the compressive yield strength, bending strength and hardness decrease. The working hardening ability and impact toughness of the 40 CrNi2 Mo steel decrease at first and then increase after tempering at 325 ℃ and 425 ℃ due to the precipitation of lamella cementite. The decrease of hardness leads to the decrease of wear resistance, and the wear mechanism gradually changes from abrasive wear to oxidation delamination wear.