双金属衬里复合管堆焊及对接焊有限元力学分析*

为研究双金属衬里复合管堆焊及对接焊焊接后焊接处应力变化，针对Φ89(8+2) mm尺寸衬里复合管，基于热-力耦合理论，建立瞬态热-固耦合管端堆焊与对接焊V型槽环焊缝轴对称力学模型。探讨衬里复合管堆焊及对接焊过程中整个焊肉及热影响区的应力变化并对应力区进行完整、详细分析。结果表明:衬里复合管焊接完成后焊区产生较高的残余应力，最高达463.47 MPa；热处理工艺消除了90%的残余应力，然而投入使用的复合管仍然存在3个高应力区:对接焊焊肉内、过渡区中靠近对接焊焊肉的基管上及2次堆焊起始点，其中应力最大的位置在2次堆焊的起始点，最高达46.63 MPa。建立的模型和计算结果可为实际工况下衬里复合管焊接部位的力学性质研究提供参考。

Finite element mechanical analysis on surfacing and butt welding of bimetal lined composite pipe

In order to study the stress change at the welded joint of bimetallic lined composite pipe after surfacing and butt welding,an axisymmetric mechanical model of V type groove girth weld in the transient thermal solid coupling pipe end surfacing and butt welding was established based on the thermal mechanical coupling theory for the lined composite pipe with size of Φ 89 (8+2) mm.The stress change of the whole welding meat and heat affected zone during the surfacing and butt welding process of lined composite pipe were investigated,and the stress zone was analyzed in detail.The results showed that after the welding of lined composite pipe,the higher residual stress generated in the welding area,up to 463.47 MPa.The heat treatment process eliminated 90% of the residual stress,but there were still three high stress zones in the used composite pipe.for the positions in the butt welding meat,on the base pipe near the butt welding meat in the transition zone and at the starting point of second surfacing,the position with the largest stress was the starting point of second surfacing,with the maximum value of 46.63 MPa.The established model and calculation results can provide reference for the study on mechanical properties of welded joint on the lined composite pipe under actual working conditions.