摘要
残余应力分布状况是决定我国冷弯产品能否应用到高端、重大工程中的重要因素之一。本文以我国冷弯高频焊管典型产品为对象,实验研究了其弯角区域横向和纵向残余应力沿壁厚的分布和自然时效规律。结果发现,应力极值点一般出现在弯曲段中心,外表面纵向和横向残余应力皆为拉应力,内表面上角所有点及下角弯曲中心附近为压应力;横向残余应力呈现较明显的指数形式下降,自然时效最终残留的横向应力仍占母材屈服应力的60%。通过硬度测试和金相组织观察,确定了630℃保温2小时为冷弯Q345B焊管的最佳去应力退火工艺。该工艺相比厂方原退火工艺,节约能源显著。
The distribution of residual stress is one of the important factors determining whether the cold-formed products can be applied to the high-end and important projects in China. In this paper, taking typical cold-formed high frequency welded pipe products in China as study object, the distribution of transverse and longitudinal residual stress along wall thickness and the natural aging regular pattern in the corner region are studied experimentally. Results show that the stress extremum value points usually appear at the center of bending segment, longitudinal and transverse residual stress on the outer surface are tensile stress, on the inner surface, compression stress appears at all points in the upper corner and near the bending center of the lower corner. The transverse residual stress presents a significant index form decrease, and the final residual transverse stress of natural aging still accounts for 60% of base metal yield stress. By means of hardness measurement and metallographic observation, the optimum annealing process of cold-formed Q345b welded pipe at 630℃ for 2 hours was determined. The process is compared with the original annealing process in the factory,the energy is greatly saved.
作者
郑一鸣
胡雨绮
肖遥
张蓓
李亦森
胡盛德
李立新
ZHENG Yi-ming;HU Yu-qi;XIAO Yao;ZHANG Bei;LI Yi-sen;HU Sheng-de;LI Li-xin(Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education,WuHan 430081,China;WHBC-Wuhan Foreign Language School,WuHan 430022,China)
出处
《实验力学》
CSCD
北大核心
2019年第5期904-910,共7页
Journal of Experimental Mechanics
基金
省部共建耐火材料与冶金国家重点实验室基金(2014QN03)
湖北省大学生创新创业计划项目(201310488031)
