钢筋HRB400闪光对焊接头应力腐蚀研究

Stress corrosion in flash welding butt joint of steel bars HRB400

针对HRB400钢筋闪光对焊接头的应力腐蚀过程进行研究。首先进行环境试验,然后对以下5组试件进行力学性能测试:钢筋母材、钢筋母材21 d5%NaCl溶液侵泡、原始闪光对焊接头、机械加工去除焊接余高的对焊接头、机械加工去除焊接余高的对焊接头21 d5%NaCl溶液侵泡及未去除焊接余高的对焊接头21 d5%NaCl溶液侵泡;并结合有限元模拟分析,最终发现焊接过程使对焊接头产生较大的应力集中,在腐蚀环境下成为混凝土中钢筋性能下降的重要原因。对比试验显示,在焊接区域和焊接夹具的位置,应力腐蚀裂纹更有可能出现。研究结果表明,必须严格控制钢筋生产的工艺过程,并有效防止腐蚀介质的侵蚀,以保证建筑物的长期安全使用。

Stress corrosion in flash welding butt joint of steel bar HRB400 is studied.Circumstance experiments and the following five groups of samples for testing mechanical properties are made：parent material samples,parent materials immersed in 5% NaCl for 21 days,original flash welding butt joints,flash welding butt joints removed the butt weld reinforcement,samples which are removed the butt weld reinforcement immersed in 5% NaCl for 21 days and original flash welding butt joints immersed in 5% NaCl for 21 days;the Finite Element Method（FEM） is applied to analyze the force of joints.The process investigation shows centralized stress combing with the corrosion condition results in the invalidation of the flash butt welding joint of reinforcing steel bar.The compared test proved that there are more probability of the stress corrosion crack within the jointure region and the clamp position in the welding joint.The results show that the designed process in the manufacture of the reinforcing steel bar and the isolation with the corroded medium can guarantee the safety of the construction.