Mechanical Properties and Tool Life of Friction-Stir-Welded DP590 Using the Si₃N₄ Tool

Abstract

Early studies have been conducted on the friction stir welding of steel, tungsten (W), molybdenum (Mo), tungsten carbide, and the like for the production of tools, but the tool materials were significantly worn out and deformed while they were being joined. So far, the polycrystalline cubic boron nitride (PCBN) tool, which is very strong at high temperatures and is wear-resistant, has performed relatively well, but the improvement of its productivity is limited by its high manufacturing cost. In this study, 1.4 mm-thick DP590 steel was subjected to FSW using the ceramic material of a Si 3 N 4 tool. The main process parameters of the butt joint at rotation speeds of 6001,000 rpm and traveling speeds of 180300 mm/min were determined through the bead-on-plate experiment. Also, the tensile strength, hardness, and Charpy impact properties of each FSW joint were evaluated, the full extent of the wear was measured and the tool life of the PCBN tool that was about four times as costly to produce was compared with the maximum joint length to determine the durability of the tool.

Friction stir welding: Process, temperature, microstructure and properties

“…The adoption of FSW for steels has quite lagged behind Al alloys since the first-generation tools were insufficient regarding their high-temperature strength, wear resistance and fracture toughness, although some initial feasibility studies on the FSW of steels were conducted by Thomas in 1999 [37]. It was then possible to weld 12 mm thick steel at a rate over 1 m min −1 by FSW [27] due to the rapid advance in tools such as WC-based-alloy tools [38][39][40][41], Si 3 N 4 tools [42][43][44], iridium-alloy tools [45] and polycrystalline cubic boron nitride (PCBN) tools [46][47][48], which suggested that the FSW technique started to become realistic to be used for steels.…”

Friction stir lap joining techniques effects on microstructure and tensile properties of high-strength automotive steel top hat sections

“…Though much research works are available on friction stir welding variants [14][15][16][17][18] of AHSS, they are limited to microstructural characteristics and basic mechanical properties in basic lap configuration. However, to gain more understanding and confirm the feasibility of using AHSS for energy absorbing and other structural applications, a study on friction stir welding on lap configuration, i.e., friction stir lap welding (FSLW) and friction stir spot lap welding (FSSLW), must be studied in detail.…”