炮钢表面激光熔覆Hastelloy C-276涂层的组织及性能

Microstructure and Properties of Laser Cladding Hastelloy C-276 Coating on Gun Steel Surface

研究Hastelloy C-276激光熔覆层的组织与性能,为炮管激光修复做好基础研究工作。利用激光熔覆系统在炮管表面制备Hastelloy C-276熔覆层,采用光学显微镜(OM)、扫描电子显微镜(SEM)、显微硬度计和电化学工作站,研究其显微组织形貌、显微硬度及耐蚀性。在炮钢表面制备的Hastelloy C-276熔覆层质量良好,无明显气孔、裂纹等缺陷,厚度约为1.2mm,组织均匀,晶粒细小,与基体结合良好。从熔覆层表面到基体的硬度分布呈先升后降趋势,熔覆层平均硬度在280 HV左右,相变区硬度最高达到500HV,基体平均硬度在350HV左右。炮管原始镀铬层的自腐蚀电位为-0.734V,自腐蚀电流密度为2.39×10-6 A/cm2,熔覆层试样的自腐蚀电位为-0.326V,自腐蚀电流密度为3.59×10-6 A/cm2,与原始镀铬层相比,熔覆层的自腐蚀电位值正移,腐蚀电流密度值稍微偏大,但仍在同一级量。采用激光熔覆技术,能够在炮钢表面制备综合质量良好的Hastelloy C-276熔覆层,且其具有优良的耐蚀性,与基体结合良好,可以部分补足身管强度。

To study the microstructure and properties of the Hastelloy C-276 laser cladding layer,and to do basic research work for laser repairing gun barrel.The cladding layer of Hastelloy C-276 was prepared on the surface of the gun steel by using a laser cladding system.The microstructure morphology,microhardness and corrosion resistance of the layer were investigated with optical microscope（OM）,scanning electron microscope（SEM）,microhardness tester and electrochemical workstation.The Hastelloy C-276 cladding layer prepared on the surface of the gun steel was of good quality and had no obvious pores,cracks,and other defects.The thickness was about 1.2 mm,uniform structure,fine grain,and good combination with the substrate.The microhardness distribution from the surface of the cladding layer to the substrate showed a trend of rising first and then decreasing.The average microhardness of the cladding layer was about 280 HV,the highest microhardness in the phase change zone was 500 HV,and the average hardness of the substrate was about 350 HV.The self-corrosion potential of original chrome plated gun barrel was-0.734 V,the self-corrosion current density was 2.39×10-6 A/cm2.The self-corrosion potential of the cladding layer sample was-0.326 V,and self-corrosion current density was 3.59×10-6 A/cm2.Compared with the original chrome plated gun barrel,the corrosion potential of the cladding layer shifts positively and the corrosion current density value was slightly larger,but it was still in the same level.Using laser cladding technology,a Hastelloy C-276 cladding layer with good overall quality could be prepared on the surface of the gun steel,and it had excellent corrosion resistance,and was well combined with the substrate,and could partially compensate for the strength of the tube.