Q235B H型钢冷弯开裂原因分析

利用宏观检验、化学成分分析、力学性能测试及金相检测等方法对Q235B H型钢冷弯开裂试样进行分析。结果表明:在冷弯试验过程中,粗大的条状塑性夹杂物和点链状脆性夹杂物与基体的结合性较差,冷弯过程中夹杂物脱落或周围应力集中形成空隙或显微裂纹,随着受力状态的加强导致裂纹扩张形成冷弯开裂的裂纹源,在开裂过程中带状组织和加工痕迹加剧了裂纹的扩大。

Cause analysis of cold bending cracking of Q235B H-beam steel

The cold bending cracking samples of Q235B H-beam steel were analyzed by macroscopic examination， chemical composition analysis， mechanical property test and metallographic examination. The results showed that in the process of cold bending test， the bonding property between thick strip plastic inclusions and point chain brittle inclusions was poor. Due to inclusion shedding or peripheral stress concentration in cold bending test， the gaps or micro cracks were formed. With the strengthening of stress， the cracks were extended to form the source of cold bending crack. The banded structure and machining marks in the process of cracking accelerated the expansion of cracks.