The present study deals with the application of sequential procedure (i.e. steepest ascent) to obtain the optimum values of process parameters for conducting friction stir welding (FSW) experiments. A vertical milling machine is modified by fabricating fixture and tool (H13 material) for performing FSW operation to join AA7039 plates. The steepest ascent technique is employed to design the experiments at different rotational speed, welding speed, and tilt angle. The ultimate tensile strength is considered as a performance characteristic for deciding the optimal levels. The mechanical and metallurgical characteristics of the joints are studied by executing tensile and microhardness tests. It is concluded from the graphical analysis of the steepest ascent technique that the optimal maximum and minimum values are 1812–1325 r/min for rotational speed, 43–26 mm/min for welding speed, and 2°–1.3° for tilt angle, respectively. Besides, optical microscope and scanning electron microscope are utilized for microstructural and fractographic analyses for a better understanding of the process.

本研究涉及顺序过程（即最陡的上升）的应用，以获得用于进行搅拌摩擦焊（FSW）实验的工艺参数的最佳值。立式铣床通过制造夹具和工具（H13材料）执行FSW操作以加入AA7039板。采用最陡峭的上升技术来设计不同转速，焊接速度和倾斜角度的实验。极限抗拉强度被认为是决定最佳水平的性能特征。通过执行拉伸和显微硬度测试，研究了接头的机械和冶金特性。根据对最陡上升技术的图形分析得出的结论是，最佳的最大值和最小值分别是转速1812–1325 r / min，焊接速度43-26 mm / min和倾斜角2°–1.3°，分别。此外，光学显微镜和扫描电子显微镜被用于微观结构和分形分析，以更好地了解该过程。