激光工艺参数对H13钢表面淬火层组织及性能影响

Effect of laser parameters on microstructure and properties of H13 steel surface quenched layer

  • 摘要: 为了探究不同激光工艺参数组合对H13钢激光淬火改性层的影响,文章设置了7组对照实验,对改性层的截面宏观形貌、物相组成、微观组织结构、显微硬度及摩擦磨损性能进行了分析,并具体对比了过烧熔凝与淬火后的组织及性能区别。结果表明,增大激光功率或减小扫描速度均能有效提高淬火区的深度和宽度,但当参数组合达到一定的界限时,会产生过烧熔凝现象,影响工件表面平整度。随着激光功率的增长或扫描速度的降低,改性层组织由不完全相变组织转变为完全相变组织;当达到一定的界限时析出的部分碳化物呈结节状特征;过烧熔凝会产生铸态枝晶组织。截面硬度随着激光功率的增加或扫描速度的降低呈现出递增的趋势,最高硬度出现在次表层区域;铸态枝晶组织相较于淬火组织使硬度显著增加。随着磨损时间的增加,激光淬火试样的磨损失重递增范围减小,磨损方式主要表现为磨粒磨损和黏着磨损。

     

    Abstract: In order to investigate the effects of different combinations of laser process parameters on the laser quenching modified layer of H13 steel, seven groups of control experiments were set up to analyze the cross-section macroscopic morphology, physical phase composition, microstructure, microhardness, and friction wear properties of the modified layer. And the difference of microstructure and properties between overburn melting and quenching was specifically compared. The results show that increasing the laser power or decreasing the scanning speed can effectively improve the depth and width of the quenching zone. However, when the parameter combination reaches a certain limit, the phenomenon of overburning melting will occur, which will affect the surface flatness of the workpiece. With the increase of laser power or the decrease of scanning speed, the microstructure of the modified layer changes from incomplete phase transformation to complete phase transformation. When reaching a certain limit, some of the carbides precipitated are nodular in character. Overburning melting results in as-cast dendrite structure. The hardness of the cross section shows an increasing trend with the increase of laser power or the decrease of scanning speed, and the highest hardness appears in the subsurface region. The as-cast dendritic structure significantly increases the hardness compared to the quenched structure. With the increase of wear time, the increasing range of wear weight loss of laser quenched samples decreases, and the wear modes are mainly abrasive wear and adhesive wear.

     

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