激光熔凝处理对压铸模具钢热疲劳性能的影响  

Effects of laser remelting treatment on thermal fatigue properties of die casting steel

作　　者：李继强[1,2] 胡树兵[1] 史华亮 贾志欣[2] 

机构地区：[1]华中科技大学材料成形与模具技术国家重点实验室,湖北武汉430074 [2]浙江大学宁波理工学院,浙江宁波315100

出　　处：《华中科技大学学报（自然科学版）》2015年第12期56-59,共4页Journal of Huazhong University of Science and Technology(Natural Science Edition)

基　　金：国家自然科学基金资助项目(51275468);国家重点基础研究发展计划资助项目(2014CB046704)

摘　　要：为了研究压铸模具钢的热疲劳性能,采用脉冲Nb:YAG激光在热处理后的Dievar钢表面进行了熔凝强化处理,并应用自约束实验考察了试样的热疲劳性能.结果表明:经激光熔凝强化后试样的热疲劳裂纹扩展速度明显比未处理试样慢,疲劳裂纹在靠近强化位置时有明显的停滞、转折和延迟扩展的现象;熔凝区的晶粒大为细化,合金元素基本均匀分布,未形成颗粒状碳化物;经激光熔凝处理后的汽车雨刷支架压铸模使用寿命由原来的2.5×104模次提高到3.8×104模次.Aiming to research the thermal fatigue behavior of die casting steel, laser remelting on sur- face of Dievar steel with quenching and tempering state was carried out by pulsed Nd. YAG laser. And the thermal fatigue properties of the samples have been studied with self-restricting test method. The results show that the propagation of thermal fatigue crack in Dievar steel treated by laser remelt- ing exhibits lower speed than that of conventional heat treatments. The fatigue crack near the laser remelting zone has been obviously stagnated, deflected and delay spread. Grain in laser remelting zone has greatly refined. The alloying elements were evenly distributed, which did not formation of granu- lar carbides. The service life of windshield wiper dies with laser remelting treatment grew from 2.5× 104 times up to 3.8× 104 times.

关 键 词：激光熔凝 压铸模具钢 微观组织 热疲劳 裂纹 

分 类 号：TG162.43[金属学及工艺—热处理]