铁含量对激光熔覆层微结构及性能的影响

为满足不同支承辊再制造表面硬度需求,利用激光熔覆技术,将添加不同含量纯铁粉的铁基合金粉末材料熔覆到Cr5支承辊钢表面。研究了铁含量对熔覆层微结构及性能的影响。结果表明,所有材料设计成分条件下熔覆层的截面组织差异很小,均为鱼骨状枝晶和网状晶间组织。通过改变添加铁粉的量可以控制熔覆层中枝晶含量。随着合金粉末中铁含量增多,激光熔覆层截面硬度和耐磨性显著下降。添加50%(质量分数)纯铁粉的粉末材料可以制备出硬度约为480HV、耐磨性高于传统淬火工作层的激光熔覆层,可以满足Cr5支承辊再制造需求。

Effect of Fe Content on Microstructure and Properties of Laser Clad Layers

In order to fulfill the demand of surface hardness of remanufacturing various backup rolls, iron based alloy powders mixed with different content of pure iron powders were prepared on Cr5 backup steel by laser claddng. Then effects of Fe content on microstructure, phases, and properties of the clad layers were investigated in this paper. Microstructure of clad layers was fishbone-like dendrites and net-like interdendritic structure. Clad layers with different fractions of dendrites could be obtained by changing the content of mixed pure iron powders. Hardness and wear resistance of layers decreased with the increase of Fe contents in mixed powder. Wear resistance of clad layer was better than traditional quenching work layer. The clad layer with a hardness of 480 HV and better wear resistance than traditional quenching work layer could be prepared by adding 50wt% pure iron powder into the mixed powder, which fulfilled the demand of remanufacturing Cr5 backup rolls.