Investigation of Friction Stir Welding Tool Wear on Different Hardening Method

The use of non-heat treated and non-hardened tool steel on normal Friction Stir Welding (FSW) application will result in severe deterioration and wear of the tool steel itself for short period of time. Therefore, the main purpose of carrying out this project is to reduce the wear of the tool by investigating the effect of hardening methods on the Friction Stir Welding (FSW) tool wear. The hardening method considered in this project are heat treatment and gas nitriding. Once the hardening process are applied to the tool steel, the wear resistance performance of the tool steel are evaluated with respect to the hardening method applied. This project is basically divided into three main parts. The first part is the welding tool fabrication, the second part is carrying out the hardening process, and the third part is performing FSW on the Al-6061 plates. The first part of the project which is the fabrication process involves the process of designing the welding tools and machining them. In the second part of the project, the fabricated tool steel will undergone several hardening process which includes the heat treatment and gas nitriding process. The third part of the project involves the FSW performed on the Al-6061 plates after the tool has been hardened. Hardness testing and wear measurement are carried out after that in order to determine and evaluate the hardness and wear of the tool. At the end of the experiment, the results obtained are analyzed in order to determine the effectiveness and feasibility of the hardening methods applied in reducing the FSW tool wear. Tool steel that is heat treated and nitrided shows the best wear resistance performance and hardness while the untreated/raw tool steel shows the worst. Meanwhile, the nitrided only tool steel shows better wear resistance performance and hardness than the heat treated only tool steel. Gas nitriding of H13 tool steel at high temperature by using nitrogen gas only is applicable and practical from this study.