再加工工艺对N18锆合金板残余应力的影响

采用“热轧+冷轧+退火”工艺对N18锆合金板进行再加工,通过X射线法分析板的表面残余应力,采用EBSD技术分析晶界取向差角分布和大小角度晶界。结果表明,热轧后N18锆合金板的表面残余应力呈现无规律分布状态;冷轧后板的表面残余应力均为压应力,其大小随着冷轧变形量的增加而增加;退火后板的表面残余应力值处于较低水平,当退火制度为500 ℃×2 h时,残余应力处于最低水平;退火后,板的微观结构以小角度晶界为主,且随着退火温度的升高,小角度晶界的密度先增加后趋于稳定。

Effect of reprocessing on residual stress of N18 zirconium alloy plate

N18 zirconium alloy plates were reprocessed through “hot rolling+cold rolling+annealing”. The surface residual stress was acquired by X-ray diffraction method. The disorientation angle distribution and the grain boundaries were analysed by means of EBSD. The results show that after hot rolling, the distribution of surface residual stress on the N18 zirconium alloy plate is no rule. After cold rolling, the surface residual stress increases with rise of cold rolling deformation quantity and entirely presents compression stress. After annealing, the surface residual stress level is low and reaches the lowest when annealing at 500 ℃ for 2 h. After annealing, the microstructure mainly consists of low angle grain boundaries, and the density of which shifts from increasing to stabilization with rise of annealing temperature.