胀接压力适宜控制范围的确定,关键在于准确计算胀接后换热管与管板间的残余接触压力.现有残余接触压力理论计算方法忽视换热管反向屈服问题,导致残余接触压力计算值与实际不符.文中基于材料理想弹塑性和平面应变假设,给出了 Mises屈服准则下胀接残余接触压力理论计算方法详细推导过程,讨论分析了换热管弹性模量、屈服强度、壁厚等变化对残余接触压力的影响,该方法可适用于先焊后胀胀接工艺下胀接残余接触压力预测.
The key to determining the appropriate control range of the expansion pressure is to accurately calculate the residual contact pressure between the heat exchange tubes and the tubesheets after expansion.The existing theoretical calculation methods of residual contact pressure ignore the reverse yielding problem of the heat exchange tubes,which leads to the calculation value of residual contact pressure is inconsistent with the actual value.Based on the assumption of ideal elastic-plastic and plane strain of materials,a detailed derivation process of the theoretical calculation method for residual contact pressure in expansion joints under the Mises yield criterion is presented in this paper.The influence of changes in elastic modulus,yield strength,wall thickness,etc.of heat exchange tubes on residual contact pressure is discussed and analyzed.This method can be applied to predict residual contact pressure in expansion joints under the process of welding first and then expanding.