特高压输电工程Q420大规格角钢断裂失效分析

Analysis on Fracture Failure of Large Angle Q420 Steel for UHV Transmission Project

利用光学显微镜、扫描电镜、力学性能测试和夏比冲击等测试方法,研究了输电铁塔用Q420大规格角钢的断裂失效行为,主要通过金相组织、力学性能、断口分析、夹杂物分析等方面分析了角钢大裂纹可能产生的原因,同时系统分析了大规格角钢裂纹的密集程度。结果表明,断裂角钢的化学成分、力学性能均满足国标要求。断口分析表明角钢为脆性解理断裂,夹杂物颗粒较大,主要为保护渣成分,同时也存在横纵裂纹,密集程度较高。最后对输电铁塔选材给出了建议。

The fracture behavior of large angle Q420 steel was studied by means of optical microscope,scanning electron microscope,mechanical property test and Charpy impact. The fracture behavior was analyzed mainly by metallographic structure,mechanical property,fracture analysis and inclusions analysis,in order to identify the reason of the crack and the density of the crack in the large angle.The results show that the chemical composition and mechanical properties of fractured steel meet the requirements of national standard.Fracture appearance observation indicates brittle cleavage fracture,and large inclusions particles which aremainly the protective residue composition,and the a higher intensity of transverse cracks as well.