N80油管激光合金化层的组织及性能研究

在N80油管表面预置Ni-Cr-Ti-B_4C合金粉末.通过激光处理获得与基体完全冶金结合的合金化层.利用金相显微镜、X射线衍射仪、扫描电子显微镜、能谱仪、电子探针显微分析仪和显微硬度计对合金化层的组织、相结构及显微硬度进行了测试分析,利用电化学测试系统测试了合金化层的耐蚀性.结果表明,激光合金化区主要由TiC、TiB_2颗粒、α-(Fe,Ni,Cr)同溶体组成;合金化区与基体结合致密、组织细小、合金化元素分布均匀;与基体相比,合金化层硬度比基体提高2～3倍,耐蚀性也得到很大改善.

Microstructure and Properties of Laser Alloying Layers on N80 Oil Tube

The N80 oil tube surface was preset Ni-Cr-Ti-B_4C alloying powders, the alloying layer which was metallurgical bonding with substrate was obtained through laser treatment. The microstructure, phases, and microhardness of laser alloying layer were tested by optical microscopy, X-ray diffraction, scanning electron microscopy, energy disperse spectroscopy, electron probe microanalysis and microhardness tester. The corrosion resistance was also tested by electrochemical corrosion testing equipment. The results show that laser alloying zone is composed of TiC grain, TiB_2 grain, and α-(Fe, Ni, Cr) solid solution. The bonding strength between the alloying zone and substrate is dense, the microstructure of crystal grain is tiny and the distribution of alloying element is uniform. Compared with the substrates the hardness of alloying layer is about 2～3 times higher than the substrate; the corrosion resistance is also obviously enhanced.