熔池尺寸对在役焊接烧穿失稳的影响

Influence of molten pool size on burn-through during inservice welding

关键词:  在役焊接  烧穿  熔池尺寸  温度场

Key words:  in-service welding  burn-through  molten pool size  temperature field

摘要:

采用大型通用有限元分析软件ANSYS,计算不同的熔池在特定温度场下,径向变形随压力的变化规律,来探究不同熔池尺寸对在役焊接烧穿失稳的影响.结果表明,对于某一特定熔池尺寸,温度场维持不变时,当管壁受压力较小时,内壁温度最高点的变形为内凹变形,随压力增大,变形逐渐变为外凸,变形随压力增加呈线性变化;但当压力超过一定值时,变形随压力不再呈线性变化,变形迅速增加;对不同的熔池尺寸,当熔深、压力一定时,熔池长度、宽度越小,其失稳温度越高.当熔深、内壁最高温度相同时,熔池长度、宽度越小其失稳压力越大.

Abstract:

In order to study the influence of the molten pool size on the burn-through during in-service welding,this paper investigated the radial deformation variation law with the change of internal pressure for different molten pools under specific temperature field with commercial software code ANSYS. The results show that when the temperature field remained constant and the internal pressure in the pipe was low,the value of radial deformation of the node,which had the highest temperature on inner surface of the pipe,was negative for one given molten pool. With the increase of pressure,the radial deformation of the node became positive and the radial deflection increased linearly. However,when the pressure exceeded a certain value,the linear change vanished and the radial deformation increased severely. For different molten pool sizes,when the penetration and pressure remained constant,the less the width and length of molten pool,the higher the instability temperature. When the penetration and the highest temperature on the inner surface of the pipe remained unchanged,the less the width and length of molten pool,the higher the instability pressure.