LD冷作模具钢激光表面熔凝

发布时间：2018-07-29 17:29

【摘要】：研究了冷作模具LD钢经不同工艺参数激光熔凝处理后的显微组织及性能。结果表明,激光功率P=3500 W,扫描速度v=20 mm/s,光斑直径d=5 mm时,处理效果较为理想。由表及里依次为熔凝层、淬火层、热影响层和基体。熔凝层又依次分为表层等轴晶区,柱状晶区和等轴晶+胞状晶区。等轴晶区和柱状晶区原有的带状、块状碳化物全部溶解,胞状晶区原有的碳化物基本保持原状,新晶粒明显细化并均匀分布。硬化层总深度可达1.0 mm;平均硬度可提高15%左右,耐磨性和耐腐蚀性显著提高。如果能量密度过大,在熔凝层容易产生微裂纹甚至宏观裂纹,破坏材料性能。
[Abstract]:The microstructure and properties of LD steel of cold working die treated by laser melting with different technological parameters were studied. The results show that the processing efficiency is satisfactory when the laser power is 3 500 W, the scanning speed is 20 mm / s, and the spot diameter is 5 mm. The order from surface to interior is melting layer, quenching layer, heat affected layer and matrix. The melting layer is divided into the surface equiaxed crystal zone, the columnar crystal zone and the equiaxed crystal cell crystal area in turn. The carbides in the equiaxed and columnar regions are completely dissolved, and the original carbides in the cellular crystalline regions remain basically the same, and the new grains are obviously refined and uniformly distributed. The total depth of hardened layer can reach 1.0 mm, the average hardness can be increased by about 15%, and the wear resistance and corrosion resistance can be improved significantly. If the energy density is too high, microcracks or even macroscopic cracks will occur in the melting layer, which will destroy the properties of the material.
【作者单位】：上海工程技术大学工程实训中心;
【分类号】：TG174.4

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