扫描顺序对激光熔覆304钢组织和性能的影响

为了研究预置送粉激光熔覆304不锈钢的组织和力学性能,在27SiMn钢表面进行了预置送粉的多层累加激光熔覆实验,并根据激光扫描的先后顺序将所得到的熔覆层材料划分为四个区域。对比分析了四个区域的材料的显微组织,力学性能和拉伸断口形貌。结果表明,激光熔覆304不锈钢的显微组织表现出了定向凝固的特征,晶粒多为柱状晶,后熔覆区域的晶粒相对于先熔覆区域较为粗大。拉伸试验结果表明,后熔覆区域的拉伸性能相对于先熔覆区域较差。拉伸断口形貌表明,激光熔覆304不锈钢试样主要表现为韧性断裂,局部表现为脆性解理断裂,在断口处有夹杂现象,且夹杂现象主要出现在后熔覆区域,通过能谱分析发现夹杂物主要为金属氧化物。

Influence of the scanning sequence on microstructure and mechanical property of 304 steel by laser cladding

In order to investigate microstructure and mechanical property of 304 stainless steel by laser cladding with preset powder feeder,304 stainless steel multilayer laser cladding experiment with preset powder feeder was carried out on 27SiMn steel.According to the sequence of laser scanning,the coating materials are divided into four zones.Microstructures,mechanical properties and fracture morphology of the four zones are compared and analyzed.Results show that the microstructure of the laser cladding 304 stainless steel shows the characteristic of directional solidification,and the grain is mostly columnar grain.The grain sizes of the late cladding area are relatively larger than that of the early cladding area.The tensile test results show that the tensile property of the late cladding area is relatively poorer than that of the early cladding area.The tensile fracture morphology of laser cladding 304 stainless steel is mainly ductile fracture,and the local area is brittle cleavage fracture.There are some impurities in the fracture,and the impurities mainly appear in the late cladding area.The impurities are mainly metal oxide according to energy spectrum analysis.