高铬铸铁热电偶保护管的铸造工艺

Casting Technology for Thermocouple Protection Tubes of High Chrome Cast Iron

从化学成分、铸造工艺入手,采用熔模精密铸造工艺,成功制备出表面光洁度好,性能优良,适合批量生产的高铬铸铁热电偶保护管。对比了用不锈钢管、石墨芯棒和石英管做芯管(芯棒)进行浇注的优缺点,发现用石英管做芯管制备的保护管表面光洁,成本低,工艺成品率高。所制备的保护管硬度为HRC 58.7,组织中存在呈菊花放射状的锥体形状的碳化物,碳化物以紧密的纤维状分布在基体中,X衍射发现存在大量的(Fe,Cr)7C3,出现这种化合物会使铸件的耐磨性能提高。

Thermocouple protection tubes of high chrome cast iron with good surface finish and suitable for mass production have been successfully-made by investment casting process. The advantages and disadvantages of core tube. （rod） of stainless steel, graphite and quartz tubes were analyzed and results show that protection tubes with quartz core rod have smooth surface, low cost, high process yield. The hardness of protection tube is I-IRC 58.7. The pyramidal shape carbides were found in the microstructure. A large number of compounds （Fe,Cr）TC3 were found by X-ray diffraction, which can improve the wear resistance of castincgs.