Heat input and temperature distribution in friction stir welding

In this paper the heat input and temperature distribution during friction stir welding is investigated. The temperatures at different positions in the specimen thickness direction and perpendicular to the pin tool travel direction were recorded during welding under various welding conditions. It was found that the highest temperature in the welding seam is less that 0.8T(m). For the conditions used in this work, the temperature does not change appreciably in the specimen thickness direction. The temperature distribution perpendicular to the weld is nearly isothermal under the pin tool shoulder. Furthermore, increasing welding pressure and pin tool rotational speed increases the peak welding temperature. Finally, it is shown that the shoulder of the pin tool plays a very important role in the welding process.