Purpose

This paper aims to experimentally determine the influence of the tool shoulder depth value on the structural and strength properties of the single lap joints made of 7075-T6 aluminium alloy made with friction stir welding (FSW) technology. The aim of the preliminary tests is to optimize the parameters of joining process of thin-walled structures such as the skin-stringer joint or skin-frame joint of the aircraft fuselage. The tests were carried out for materials commonly used in such structures, i.e. 1.6 mm thick sheet 7075–T6 aluminium alloy with cladding on both sides (cladding thickness 4% per each side). The layer of clad protects plates from corrosion.

Design/methodology/approach

This study shows the results of the investigation for the joining of 7075–T6 ALCLAD aluminium alloy sheets. The welding process was carried out on a computer numerical control milling machine SOLARUCE TA–20A. Linear FSW welding was performed using a commercial tool from RSS SCHILLING with the symbol 10–K–4–Z–M–O, which is fabricated of hot work tool steel. Constant parameters of the technological process were applied. The welding process was executed for different values of the shoulder depth ZS.

Findings

This paper investigated the dependence between the thinning of the welded material and the depth value of the tool shoulder during the FSW process. The influence of the depth value of tool shoulder on joint strength in the static tensile/shear test was also performed. With the increase of the depth of the tool, the size of flash and structures of the face of the joint changes as well (its annular surface resulting from the tool’s work and the accompanying process of material flow on the run-off side). Such conditions in the process require a proper tool depression to reduce the occurrence of flash and minimize material thinning to achieve high joint strength and maintain the conditions for plasticizing the material.

Practical implications

Based on the experimental tests carried out, a number of guidelines for the correct conduct of the welding process can be outlined.

Originality/value

Taking into account the various aspects of the process, the optimal range of the tool depth into the material is a value of approximately 0.06 mm. At this value, the face of the weld is not porous; the flash is easily removed; and the strength of the joint and the deformation of contact line are at an acceptable quality level.

中文翻译：

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肩深对FSW技术制成的薄板接头性能的影响

目的

本文旨在通过实验确定刀肩深度值对7075-T6铝合金搅拌摩擦焊（FSW）技术制成的单搭接接头的结构和强度性能的影响。初步测试的目的是优化薄壁结构的连接过程参数，例如飞机机身的皮肤纵梁接头或皮肤框架接头。对此类结构中常用的材料进行了测试，即1.6毫米厚的7075–T6铝合金薄板的两面都有覆层（覆层厚度每侧4％）。包层保护板免受腐蚀。

设计/方法/方法

这项研究显示了对7075-T6 ALCLAD铝合金薄板连接的调查结果。焊接过程在计算机数控铣床SOLARUCE TA-20A上进行。使用RSS SCHILLING的商业工具执行线性FSW焊接，其符号为10–K–4–Z–M–O，由热加工工具钢制成。应用了工艺过程的恒定参数。对肩深ZS的不同值执行焊接过程。

发现

本文研究了FSW过程中焊接材料变薄与刀肩深度值之间的关系。在静态拉伸/剪切试验中，还进行了刀肩深度值对接缝强度的影响。随着工具深度的增加，毛边的尺寸和接缝表面的结构也发生变化（其环形表面是由于工具的工作以及伴随着物料在下流侧的流动而产生的）。该过程中的这种条件要求适当的工具下压，以减少溢料的发生，并使材料变薄最小化，以实现较高的接合强度，并保持使材料塑化的条件。

实际影响

根据进行的实验测试，可以概述有关正确进行焊接过程的许多准则。

创意/价值

考虑到过程的各个方面，工具进入材料的最佳深度范围约为0.06 mm。在此值时，焊缝表面不是多孔的。闪光灯很容易移除；接头的强度和接触线的变形处于可接受的质量水平。