A method of laser-hardening using an oscillating beam was utilized to locally increase mechanical properties of laser powder bed fusion (LPBF) manufactured thin-walled specimens made of medium manganese steel. Those results showed a martensite microstructure was obtained in the hardened zone over the entire depth of the specimen and indicated its suitability for laser hardening. The average hardness of the fully hardened zone increased from 300 HV to approximately 440 HV. The martensitic transformation caused an increase in the ultimate tensile strength (UTS) and yield strength (YS) of 66 % and 28 %, respectively, and decreased the level of ductility to 5% of elongation. Fracture analysis of the tensile specimens showed shallow dimples in the center and shear lips on the edges and in the laser hardened zones. The crack was initiated by the lack of fusion just below the surface and was characteristic for LPBF material tensile specimens. Based on bending tests, improper localization of the local hardened zones in the component, i.e. in areas of high plastic deformation, led to the formation of a microcrack due to a significant reduction in ductility and microstructural inhomogeneities. The knowledge of the strategy and technological parameters of the hardening process of heat-treated LPBF medium manganese steel will be beneficial to the automotive industry as this material class is gaining increasing attention.

一种使用振荡光束的激光硬化方法用于局部提高激光粉末床熔合 (LPBF) 制造的中锰钢制成的薄壁试样的机械性能。这些结果表明，在整个试样深度的硬化区域中都获得了马氏体微观结构，并表明其适用于激光硬化。完全硬化区的平均硬度从 300 HV 增加到大约 440 HV。马氏体转变导致极限抗拉强度 (UTS) 和屈服强度 (YS) 分别增加了 66% 和 28%，并将延展性水平降低到伸长率的 5%。拉伸试样的断裂分析显示中心有浅凹坑，边缘和激光硬化区域有剪切唇。裂纹是由于表面下方缺乏熔合而引发的，并且是 LPBF 材料拉伸试样的特征。基于弯曲试验，部件中局部硬化区域的不正确定位，即在高塑性变形区域，由于延展性和微观结构不均匀性显着降低而导致形成微裂纹。了解热处理 LPBF 中锰钢的硬化过程的策略和技术参数将有利于汽车工业，因为这种材料类别正受到越来越多的关注。由于延展性和微观结构的不均匀性显着降低，导致形成微裂纹。了解热处理 LPBF 中锰钢的硬化过程的策略和技术参数将有利于汽车工业，因为这种材料类别正受到越来越多的关注。由于延展性和微观结构的不均匀性显着降低，导致形成微裂纹。了解热处理 LPBF 中锰钢的硬化过程的策略和技术参数将有利于汽车工业，因为这种材料类别正受到越来越多的关注。