胀接工艺对镍基合金换热管残余应力的影响

胀接残余拉伸应力是造成核岛换热设备换热管应力腐蚀开裂的主要原因。选取SB -163 UNS N06690镍基合金换热管开展胀接试验，检测分析换热管胀接残余应力。研究结果表明：换热管胀接过渡区残余拉应力最大，胀接区域次之，未胀接区域最小；机械胀接工艺使管子变形量明显大于液压胀接，过渡区域残余拉应力相对较大，且随壁厚减薄率的增加而变大。

Influence of Expanding Process on Residual Stress of Nickel-Base Alloy Tubes

Residual tensile stress caused by expanding was the major factor lead to stress corrosion crack-ing on nuclear heat exchangers tubes.Experimental research of residual stress in expanded SB-163 UNS N06690 tubes was carried out with hydraulic expansion and mechanical rolling processes.The results show that,maximum residual stress was located at expansion transition zone and minimum value located at un-expanded zone.Deformation of mechanical rolling was larger than hydraulic expansion and results in high-er residual stresses.Residual stresses in transition zone increase with wall reduction.