Defects over the standard of an enhanced high-nickel-chrome roll were investigated by means of optical microscope, scanning electron microscope and energy dispersive spectrometer. The experimental results show that a large number of inclusions exist in the working layer of improved high nickel-chrome composite roll and result in echoes detected by ultrasonic inspection; the shapes are spherical or ellipsoidal and sizes are from 100μm to 300μm, the inclusions distribute near the binder layer; the inclusions are composed of Al, Ti, Si, Ca, O, etc., are composite inclusions out of which niobium carbides exist. The inclusions mainly originate from raw materials, which can be effectively reduced by strictly controlling the impurity elements in pig iron, and the reject rate can be reduced.%改进型高镍铬复合轧辊缺陷超标,采用光学显微镜、扫描电镜和能谱仪分析了轧辊缺陷.试验结果表明:改进型高镍铬复合轧辊工作层中存在聚集的夹杂物,导致超声波探伤出现大量回波;夹杂物呈球状或椭球状,尺寸为100~300μm,分布在靠近结合层位置;夹杂物含Al、Ti、Si、Ca、O等元素,为复合型夹杂物,夹杂物外层吸附很多碳化铌.这种夹杂物主要来自原材料,通过严格控制生铁中的杂质元素,可有效减少改进型高镍铬复合轧辊中夹杂物的产生,降低废品率.
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