Araque Oscar, Arzola Nelson
Departamento de Ingeniería Mecánica, Universidad de Ibagué, Ibagué 730001, Colombia.
Department of Mechanical and Mechatronics Engineering, National University of Colombia, Bogota 111321, Colombia.
Materials (Basel). 2018 Jan 5;11(1):81. doi: 10.3390/ma11010081.
The objective of this research is to develop an experimental-theoretical analysis about the influence of the cooling medium and the geometry of the welding bead profile in fatigue life and the associated parameters with structural integrity of welded joints. A welded joint with cruciform geometry is considered using SMAW (Shielded Metal ArcWelding), plates in structural steel ASTM A36 HR of 8 mm of thickness, and E6013 electrode input. A three-dimensional computational model of the cruciform joint was created using the finite element method. For this model, the surface undulation of the cord and differentiation in the mechanical properties of the fusion zone were considered, the heat-affected zone (HAZ) and base material, respectively. In addition, an initial residual stress field, which was established experimentally, was considered. The results were a set of analytical expressions for the weld magnification factor M. It was found that values for the latter decrease markedly in function of the intensity of the cooling medium used in the post welding cooling phase, mainly due to the effect of the residual compressive stresses. The obtained models of behavior of the weld magnification factor are compared with the results from other researchers with some small differences, mainly due to the inclusion of the cooling effect of the post weld and the variation of the leg of the weld bead. The obtained analytical equations in the present research for M can be used in management models of life and structural integrity for this type of welded joint.
本研究的目的是开展一项实验理论分析，探讨冷却介质和焊缝轮廓几何形状对疲劳寿命的影响以及与焊接接头结构完整性相关的参数。采用手工电弧焊（SMAW），考虑一个十字形几何形状的焊接接头，使用厚度为8mm的ASTM A36 HR结构钢板材和E6013焊条。利用有限元方法创建了十字形接头的三维计算模型。对于该模型，分别考虑了焊缝表面起伏以及熔合区、热影响区（HAZ）和母材的力学性能差异。此外，还考虑了通过实验建立的初始残余应力场。结果得到了一组关于焊缝放大系数M的解析表达式。研究发现，焊缝放大系数的值在很大程度上取决于焊接后冷却阶段所使用冷却介质的强度，这主要是由于残余压应力的作用。将所得到的焊缝放大系数行为模型与其他研究人员的结果进行比较，存在一些细微差异，主要原因是考虑了焊后冷却效果和焊缝焊脚的变化。本研究中得到的关于M的解析方程可用于此类焊接接头的寿命和结构完整性管理模型。
