Advanced numerical modelling of friction stir welded low alloy steel

The development of advanced joining processes such as friction stir welding (FSW) is necessary to maintain manufacturing competitiveness in any industrial nation. Substantial research that has been carried out on FSW of aluminium alloys has demonstrated considerable benefits; this has led to greater interest in FSW of steel and other high melting temperature alloys. In this context, numerical modelling can provide cost-effective development of steel FSW. Due to the limitations associated with the Johnson Cook model when employed in high melting temperature metals, a three-dimensional thermo-mechanical simulation of FSW featuring low alloy steel with previously generated experimental temperature dependant properties has been successfully solved in Abaqus/Explicit. Unlike any previous research in which either the workpiece is assumed as a high viscous body or the tool is modelled as a moving heating source, the Coupled Eulerian Lagrangian approach has been in-novatively applied to model the FSW process on steel. All stages of FSW (plunge, dwell and traverse) have been modelled for slow and fast process parameters and their results compared with previous experimental work on the same grade of steel. In each model, the weld shape and weld surface flash were found to be in exceptionally close alignment with previous experimental results.

诸如搅拌摩擦焊（FSW）等先进连接工艺的发展对于任何工业国家保持制造业竞争力都是必要的。对铝合金搅拌摩擦焊进行的大量研究已经显示出相当大的益处；这使得人们对钢和其他高熔点合金的搅拌摩擦焊产生了更大的兴趣。在此背景下，数值模拟能够为钢的搅拌摩擦焊提供具有成本效益的研发。由于约翰逊 - 库克模型在用于高熔点金属时存在局限性，在Abaqus/Explicit中成功求解了一个以具有先前生成的随温度变化特性的低合金钢为对象的搅拌摩擦焊三维热 - 力学模拟。与以往任何将工件假定为高粘性体或将工具建模为移动热源的研究不同，耦合欧拉 - 拉格朗日方法被创新性地应用于对钢的搅拌摩擦焊过程进行建模。针对慢速和快速工艺参数对搅拌摩擦焊的所有阶段（插入、停留和行进）都进行了建模，并将其结果与先前对同一等级钢所做的实验工作进行了比较。在每个模型中，发现焊缝形状和焊缝表面飞边与先前的实验结果都极为吻合。