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本文对激光重熔20CrMnTi材料表明改性层显微组织分布特征、表面硬度分布规律以及残余应力状态作了研究,结果表明,表面改性层由熔融层、相变硬化层及过渡层组成,且材料表面显微硬度得到大幅度提高,表面硬度达到HV841,约提高4倍。硬化层深度约1mm。残余应力测试得出最大残余应力出现在熔凝带中心,表现为压应力。随着离中心距离的增大,残余应力逐步降低,到熔化带边缘,表现为低幅值压应力;而熔池的外边缘应力在热影响区则转变为拉应力状态。
In this paper, laser remelting 20CrMnTi material shows that the modified layer microstructure distribution, surface hardness distribution and residual stress state was studied, the results show that the surface modification layer by the melt layer, the phase change hardening layer and the transition layer, and Material surface microhardness has been greatly improved, the surface hardness reaches HV841, an increase of about 4 times. Hardened layer depth of about 1mm. Residual stress tests show that the maximum residual stress appears in the center of the melting zone, showing compressive stress. As the distance from the center increases, the residual stress decreases gradually to the edge of the melting zone, which shows low amplitude compressive stress. However, the outer edge stress of the molten pool changes to tensile stress in the HAZ.