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为了考察HT250灰铸铁干熄炉风帽在使用过程中发生断裂的原因,分别利用化学分析法、光学显微镜和布氏硬度计,对断裂后风帽材料的化学成分、微观组织和布氏硬度(HBW)进行了分析、观察和测定,并根据布氏硬度值计算材料的抗拉强度。结果表明,风帽材料中的铁素体含量高于HT250灰铸铁件的要求上限,在风帽非工作面附近的基体组织中,铁素体含量达50%以上;铁素体含量过高导致HT250灰铸铁风帽材料的抗拉强度低于正常,是造成风帽断裂的主要原因。
In order to investigate the cause of the fracture of HT250 gray cast iron dry-out hood, the chemical composition, microstructure and Brinell hardness (HBW) of the hood material after fracture were investigated by chemical analysis, optical microscope and Brinell hardness tester respectively Analyze, observe and measure, and calculate the tensile strength of the material according to the Brinell hardness value. The results show that the ferrite content in the hood material is higher than the upper limit of HT250 gray cast iron. In the matrix structure near the non-working surface of the hood, the ferrite content is over 50%; the ferrite content is too high to cause the HT250 gray The tensile strength of the cast iron hood material is lower than normal, which is the main reason for the hood cracking.