HRB400E钢螺纹钢筋弯曲断裂的原因分析

Analysis on Cause for Bending Failure of Reinforced Bars Made from HRB400E Steel

φ12 mm热轧HRB400E钢螺纹钢筋在使用中发生了两起弯曲断裂。对弯曲断裂的2件螺纹钢筋进行了宏观检验、化学成分分析、硬度检测、金相检验和断口检验。结果表明:弯曲断裂的螺纹钢筋因热轧后冷却较快形成了马氏体和贝氏体,硬度高、脆性大,导致其在弯曲应力作用下发生脆性断裂。

Two cases of bending failures of the hot⁃rolled reinforced bars 12 mm in diameter made from HRB400E steel occurred in service.Two pieces of reinforced bar rupturing in bending were subjected to macro⁃check,chemical composition analysis,hardness measurements,metallographic examination and fracture testing.The results showed that the reinforced bars rupturing in bending exhibited martensite and bainite which formed during rapid cooling after hot⁃rolling and had high hardness and large brittleness,thus resulting in their brittle fracture by the action of bending stress.