锅炉管表面NiCrSiB合金高频感应熔覆的数值模拟及熔覆层的性能  

Numerical Simulation of Temperature Field of High Frequency Inductive Cladding of NiCrSiB Alloy on Boiler Tube and Corrosion Resistance of the Cladding Layer

作　　者：岑虎 王云山[1] 雷剑波[1] 刘少军[2] 孟庆若[2] 

机构地区：[1]天津工业大学激光技术研究所,天津300160 [2]中国能源建设集团天津电力建设公司,天津300041

出　　处：《材料保护》2014年第2期12-15,8-9,共4页Materials Protection

基　　金：天津市科技支撑计划重点项目(11ZCKFGX 02500)资助

摘　　要：目前,管材表面的高频感应熔覆主要集中于试验方面,缺乏理论研究。对锅炉管壁在不同熔覆电流下高频感应熔覆NiCrSiB层的温度场进行了数值模拟,基于感应加热原理进行了有限元分析,并加以试验验证。采用金相显微镜、扫描电镜以及能谱仪对熔覆层的显微组织与成分进行了分析;采用硬度计及王水腐蚀分别测试了熔覆层的硬度及耐蚀性能。结果表明:在250 kHz时,熔覆电流越大,感应加热效率越高,感应加热结束时管内外壁的温差越大,管基体受到的热损伤越小;基体中的Mo元素向熔覆层扩散,熔覆层中的Si元素向基体渗透,过渡区Ni,Cr元素的含量相对熔覆层中的明显减少;熔覆频率为250 kHz,熔覆电流取830 A时,熔覆层和基体过渡区有明显锯齿状的白亮带产生,基体和熔覆层呈冶金结合,熔覆层金相组织为奥氏体+碳化物共晶,具有良好的耐蚀性能,平均硬度为323 HV,是基体的1.79倍。The temperature field on the wall of boiler tube subjected to high frequency inductive cladding under different cladding currents was numerically simulated,and relevant finite element analysis was conducted based on inductive heating principle.Furthermore,the numerical simulation results were verified by experiment.In the meantime,the microstructure and composition of the cladding layer were analyzed by metallographic microscopy,scanning electron microscopy and energy dispersive spectrometry.The hardness of the cladding layer was determined with a hardness meter,and its corrosion resistance was evaluated based on corrosion test in nitrohydrochloric acid.Results showed that,at a cladding frequency of 250 kHz,the efficiency of inductive heating and the temperature difference between the inner and outer walls of the boiler tube tended to increase with increasing electric current.Mo in the substrate tended to diffuse into the cladding layer while Si in the cladding layer tended to diffuse into the substrate,and the content of Ni and Cr elements in the transition zone was much lower than that in the cladding layer.At a cladding frequency of 250 kHz and a cladding current of 830 A,a serrate white band was formed at the transition zone between the cladding layer and the metal substrate,and the substrate and the cladding layer were combined by metallurgical bonding.Besides,the cladding layer consisted of austenite and eutectic carbide.Its average hardness was 323 HV which was 1.79 times as much as that of the substrate,while it exhibited good corrosion resistance as well.

关 键 词：高频感应熔覆 NiCrSiB熔覆层 锅炉管 熔覆温度场数值模拟 耐蚀性能 

分 类 号：TG174.44[金属学及工艺—金属表面处理]