冷拔残余应力应变对钢丝氢扩散过程的影响  

INFLUENCE OF RESIDUAL STRESS AND STRAIN GENERATED BY COLD DRAWING ON HYDROGEN DIFFUSION PROFILES OF STEEL WIRES

作　　者：王艳飞[1] 巩建鸣[1] 唐建群[1] 蒋旺[1] 姜莹洁[1] 

机构地区：[1]南京工业大学机械与动力工程学院,南京210009

出　　处：《中国腐蚀与防护学报》2011年第3期202-207,共6页Journal of Chinese Society For Corrosion and Protection

基　　金：江苏省"六大人才高峰"基金项目(06-D-035);江苏省工业装备数字制造及控制技术重点实验室基金项目(BM2007201)资助

摘　　要：利用有限元法对高强度珠光体钢丝冷拔残余应力应变进行有限元分析,在此基础上利用有限差分法计算应力应变同时诱导下的氢扩散浓度分布规律,并比较其与只考虑残余应力诱导氢扩散模型所得氢浓度分布规律的不同。结果表明,由于冷拔加工过程中钢丝表面和内部变形速率的差异,冷拔后在钢丝表面产生较大的残余拉应力和大量的塑性应变。残余应力应变的存在,加剧氢在材料中的扩散和聚集,其中应变的影响相当明显。在短时间内,由于塑性应变降低氢在材料内的扩散系数,所以同时考虑残余应力和应变引起的氢富集水平低于只考虑应力诱导引起的氢富集水平。随着时间的增加,应力应变引起的氢富集浓度明显大于只考虑应力诱导时的氢富集浓度。塑性应变会引起氢富集已经被大量实验所证实,同时考虑应力应变对氢扩散的影响更具有实际意义,为进一步建立准确的钢丝氢脆模型提供参考。High strength steel wires are susceptible to hydrogen induced fracture. It is generally considered that fracture will occur when a critical hydrogen concentration at the location of the stress peak was reached by accumulation, and that the time to fracture was related to the stress assisted hydrogen diffusion process. Residual stresses generated by cold drawing play an important role in hydrogen accumulation. However, plastic strain also has significant effect on the hydrogen diffusion process. In this paper, a numerical model was developed for calculating the accumulated hydrogen concentration in cold drawn steel wires, taking into account the driving effect of both the residual stress and strain generated by cold drawing on hydrogen transport. First, a finite element model, using the code ABAQUS, was developed to reproduce the drawing process, and to determine the residual stress and strain profiles. The results showed that the drawing process generated a residual stress state in the wire with significant tensile stresses at the surface in the axial and hoop directions. Finite difference method was used to solve the stress-strain assisted and stress-only assisted hydrogen diffusion equations. The hydrogen concentration accumulated in stress-strain assisted case is lower than that in stress- only assisted case in shorter time, that was slowed down by plastic strain due to diffusion. However, after long exposure time, the hydrogen concentration was much higher than that in stress-only affected case. The results in this paper prove the relevant role of residual plastic strain in hydrogen diffusion in cold drawn wires, as well as the residual stress.

关 键 词：冷拔 残余应力 应变 氢扩散 钢丝 

分 类 号：TG457[金属学及工艺—焊接]