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堆焊修复夹送辊因材料选用不当或材料纯度不高,即使堆焊工艺及热工艺处理得当也常出现热裂纹.通过模拟堆焊夹送辊,找到热裂纹裂纹源,光学显微镜和扫描电镜观测裂纹表面和冲断面.结果表明,网状环向分布的裂纹是由主裂纹和围绕在主裂纹附近的微裂纹组成;主裂纹内碳、硫、氧含量较高,它们相互作用,相互促进,形成数量众多的低熔点共晶体;同时这些杂质易于富集盖面层表面的晶界或晶枝之间,使结晶裂纹易于产生和扩展.而微裂纹内含有大量的氧化物,氧化物的偏析和聚集是形成微裂纹的原因.
Surfacing repair pinch roll due to improper material selection or material purity is not high, even if the surfacing process and thermal process properly also often appear hot cracks. By simulating surfacing pinch roll to find the source of hot crack cracks, optical microscopy and scanning electron microscopy The crack surface and the rupture plane were observed.The results show that the reticular ring-shaped crack is composed of the main crack and the micro-crack surrounding the main crack, and the content of carbon, sulfur and oxygen in the main crack is high, and they interact and promote each other , Forming a large number of low-melting point eutectic; at the same time these impurities tend to enrich the surface of the cover layer grain boundaries or crystal branches, the crystal cracks easy to produce and extend the micro-cracks contain a lot of oxide, oxide segregation And aggregation is the reason for the formation of microcracks.