H13钢单光斑重熔的微观组织与硬度分布特征  

Microstructure and hardness distribution characteristics of single spot remelted H13 steel

作　　者：阿那尔 胡方勤 张青科 崔杰 宋振纶 ANAER;HU Fang-qin;ZHANG Qing-ke;CUI Jie;SONG Zhen-lun(School of Materials Science and Chemical Engineering,Ningbo University,Ningbo 315211,China;Key Laboratory of Advanced Marine Materials,Ningbo Institute of Materials Technology and Engineering,Chinese Academy of Sciences,Ningbo 315201,China;Zhejiang Huashuo Technology Co Ltd,Ningbo 325806,China)

机构地区：[1]宁波大学材料科学与化学工程学院,浙江宁波315211 [2]中国科学院宁波材料技术与工程研究所海洋关键材料重点实验室,浙江宁波315201 [3]浙江华朔科技股份有限公司,浙江宁波325806

出　　处：《材料热处理学报》2025年第3期191-199,共9页Transactions of Materials and Heat Treatment

基　　金：宁波市科技创新2025重大专项(2022Z012)。

摘　　要：激光重熔是提升热作模具钢表面性能的主要手段之一,但由于光斑能量分布不均及光斑间的交互影响,易发生重熔层表面硬度和厚度不均匀的问题。为此,进行了不同热输入的H13钢单光斑重熔试验,分析了重熔斑的微观组织和成分、测量了表面和截面硬度分布,希望揭示重熔层组织和硬度不均的根源。结果表明:重熔斑直径约为0.6 mm,表面边缘凸起而中心凹陷,其组织为从熔池边缘向内部生长的精细柱状枝晶,中心有凝固疏松,热输入较大时出现微裂纹;重熔层范围内实现了微区成分均匀化。重熔层和热影响区呈半透镜状,厚度随热输入增加而显著增大。重熔层硬度在600~800 HV0.05之间,从熔池边缘向中心逐渐降低,热影响区硬度从700 HV0.05降至约220 HV0.05。在光斑的范围内,相同深度、不同位置的硬度有明显差异。Laser remelting is one of the main methods to improve the surface performance of hot-working die steel,but due to the uneven distribution of spot energy and the interaction between spots,uneven surface hardness and thickness of the remelted layer are prone to occur.For this purpose,single spot remelting experiments with different heat inputs were conducted on H13 steel,then the microstructure and composition of the remelted spots were characterized,and the surface and cross-sectional microhardness were measured,in order to reveal the reason for the uneven microstructure and hardness of the remelted layer.The results show that the diameter of the remelted spot is about 0.6 mm,with a raised surface edge and a concave center.Its microstructure consists of fine columnar dendrites growing from the edge of the melt pool to the center,with solidification porosity in the center,and microcracks appear when the heat input is high.The uniformity of micro zone composition has been achieved within the range of the remelted layer.The remelted layer and heat affected zone are semi lens shaped,and their thickness significantly increases with increasing heat input.The hardness of the remelted layer ranges from 600 HV0.05 to 800 HV0.05,gradually decreasing from the edge of the molten pool towards the center.The hardness of the heat affected zone decreases from 700 HV0.05 to approximately 220 HV0.05.Within the range of the spot,there are significant differences in hardness at the same depth of different positions.

关 键 词：热作模具钢 激光重熔 单光斑 凝固组织 显微硬度 

分 类 号：TG174.44[金属学及工艺—金属表面处理]