Cr20Ni80电热合金丝的加热失效分析  

Analysis on Heating Failure of Cr20Ni80 Electrothermal Alloy Wire

作　　者：王晓军[1] 张小刚[1] 夏天东[1] 董生贸[2] 

机构地区：[1]兰州理工大学材料科学与工程学院,甘肃兰州730050 [2]金川集团股份有限公司,甘肃金昌737104

出　　处：《热加工工艺》2017年第12期256-258,261,共4页Hot Working Technology

基　　金：甘肃省战略新兴产业专项项目(2012-672)

摘　　要：采用20A恒流直流电源对长30 mm、直径0.8 mm的Cr20Ni80电热合金丝持续通电加热氧化。研究了Cr20Ni80合金丝氧化失效过程中电阻和晶粒大小的变化。通过SEM和EDS对该合金丝的组织及氧化膜进行研究。结果表明:该合金丝烧断后,小晶粒变成大晶粒,电阻增大,并产生磁性;横断面基体表面产生坑洞,边缘坑洞多,中心坑洞少;合金丝周围产生一层致密的氧化膜,氧化膜最外层是NiO层,氧化膜最内层是Cr_2O_3层;Si元素存在于氧化膜的两侧,阻碍氧的扩散,提高了合金的高温抗氧化性能,同时提高了镍基合金的塑性。Cr20Ni80 electric alloy wire with the length of 30 mm and diameter of 0.8 mm was heated by 20 A constant current DC power. The change of electrical resistance and grain size of Cr20Ni80 electrothermal alloy wire during heating and failure process was researched. The microstructure and oxidation film of the alloy wire were studied by SEM and EDS. The results show that when the alloying wire is burnout, small grains turn into large grains, and the resistance increases,then, the magnetism appears. Holes appear on the surface of the cross-sectional of matrix. Many holes form around the outside and are fewer in the center. A dense oxide film appears on the surface of the wire. The ouflayer of the film is NiO layer, while the inner layer of the film is Cr203. Si element appears at the both sides of the film, which can restrain the diffusion of oxygen and increase the high temperature oxidation resistance of the alloy, and at the same time, the plasticity of the nickel-based alloy improves.

关 键 词：Cr20Ni80电热合金 电热丝 电阻率 氧化膜 

分 类 号：TG146[一般工业技术—材料科学与工程]