Abstract:
Friction welding has become increasingly popular in industrial work as the method offers numerous advantages including no metal fillers required, and short welding time. However, due to very high heat generated at the joint being welded, changes affecting mechanical properties at microstructure of the welding material occur.
The research examines parameters affecting the friction welding of AISI 304 stainless steel pipe and shaft specimens with an outside diameter of 32 mm, an inside diameter of 26 mm, and 100 mm in length. The conditions exerted while welding involved the speed of 2500 rpm/min, the prepressure under 20 bars at 10 seconds, compression pressures under 25, 30 and 35 bars at the compression intervals of 5, 7 and 9 seconds, respectively. After the welding, the mechanical properties of specimens were tested and compared with those obtained by means of TIG welding. This included tensile test, hardness test, and the examination of both the macrostructure and microstructure of specimens with optimum parameters.
The results were summarized as the following. Increase of pressure level and time of pressure affected the burr size of the workpieces. Increase of heat during the melting affected the penetration of melting and the strength of joints, which increased the tensile strength of the workpieces. The increase of tensile strength resulted from reduction of the size of grains and the space between them. It was concluded that suitable parameters for maximum strength were compression pressure under 35 bars, and the compression time of 9 seconds.