通过宏观检验、化学成分分析、力学性能测试、金相检验和硬度测试对矿山巷道支护用36U型钢弯曲性能不合格的原因进行了分析。结果显示: 碳和硅含量超标,锰含量严重超标,使组织中出现较多贝氏体,且铁素体含量降低,同时其硬度比正常型钢的硬度高近一倍,最终导致其性能异常,发生弯曲脆性断裂。

By means of macro examination,chemical composition analysis,mechanical properties test,metallographic examination and hardness test,the bending property unqualified reason of 36U support profile steel used in mine tunnel was analyzed. The results showed that the main reason was that the content of C and Si exceeded standard,the content of Mn exceeded standard consumedly,large amounts of bainite and less ferrite were produced,and the hardness was a times more than the normal hardness,led to the property of 36U profile steel was abnormal and the brittleness fracture happened in bending process.