高压聚乙烯反应管自增强残余应力松弛研究

Experimental study of autofrettaged residual stress relaxation.

针对高压聚乙烯反应管在服役期间的自增强残余应力松弛现象 ,根据反应管的服役条件 ,分析了正常服役条件下反应管自增强残余应力松弛的原因 ,指出了影响反应管自增强残余应力松弛的主要因素是正常操作时的稳态平均温度场和开停工循环压力 ;通过自增强厚壁圆筒在循环压力和均匀温度场单独和综合作用下的残余应力松弛试验 ,建立了高压聚乙烯反应管自增强残余应力松弛量的工程算式。研究表明 ,高压聚乙烯反应管仅受到正常服役时的开停工循环压力和操作温度作用时 ,在其 2 0a的寿命期内 ,反应管壁内仍有 4

According to the normal working conditions of tubular reactor of high-pressure polyethylene, factors affecting the relaxation of residual stress in autofrettaged reactor are analyzed, and the relaxation law of residual stress in autofrettaged thick walled cylinder is experimentally examined. An experiential formula to calculate the relaxed amount of residual stress under cyclic pressure and/or temperature is extablished with the experimental results and theory. It is pointed out that the relaxation of residual stress is mainly caused by the average operating wall temperature and cyclic start-stop operating pressure; and the maximum relaxed rate of residual stress will be only 53% if the reactor does not suffer from thermal shock within its life cycle.