大容积无缝气瓶瓶口外螺纹修复方法及安全分析

为确定不同瓶口壁厚气瓶的外螺纹修复方式，采用数值和理论方法，通过分析外螺纹修复后气瓶的瓶体应力分布、周向转动和轴向窜动情况，对直接加工和采用热套工艺加装衬环2种瓶口外螺纹修复方式的安全性进行评价。结果表明:针对内螺纹规格为3-1/4″-8UN的气瓶，当采用直接加工方式将外螺纹修复至4-1/2″-8UN时，气瓶最大应力位于气瓶筒体上，此时气瓶可安全使用；当已修复至4-1/2″-8UN的瓶口外螺纹再次出现磨损时，直接加工的修复方式会对气瓶的安全使用造成影响，应采用热套工艺加装衬环方式修复瓶口螺纹。

Repair method for external thread on mouth of large capacity seamless gas cylinder and safety analysis

In order to determine the repair method for the external thread on the mouth of gas cylinders with different wall thicknesses,the numerical and theoretical methods were used to analyze the stress distribution,circumferential rotation and axial movement on the cylinder body of gas cylinder after the repair of external thread,and the safety of two kinds of repair method for the external thread on the mouth including the direct machining and the installing of liner ring with the shrink fit process were evaluated.The results showed that aiming at the gas cylinder with the internal thread specification of 3-1/4″-8UN,when the gas cylinder was repaired to 4-1/2″-8UN by using the direct machining method,the maximum stress of gas cylinder was located at the shell of gas cylinder,and the gas cylinder could be used safely at this time.When the external thread on the mouth after repairing to 4-1/2″-8UN appeared the wear again,the repair method of direct machining would cause the influence on the safe usage of gas cylinder,so the method of installing liner ring with the shrink fit process should be used to repair the thread on the mouth.