Mechanical Characterization of Friction Welded AISI 304 Steels

There are many industries where austenitic stainless steel needs to be welded specially in power generation industries. Unfortunately the austenitic stainless welding has several fabrication and metallurgical drawbacks when welded by using conventional fusion welding methods, which can often leads to in-service failure. The most pronounced fabrication faults are hot cracks due to inadvertent use of incorrect welding electrodes, primarily carbon steel electrodes. The use of carbon steel electrode results in the formation of very hard, crack-susceptible bulk structure on the stainless steel side. Such hard and brittle zones may render to localized pitting corrosion attack, hydrogen embrittlement, sulfide stress cracking, and stress rupture. Thus conventional fusion welding of many metalsare not feasible owing to the formation of brittle and low-melting inter-metallic. Solid state welding processes that limit extent of intermixing are generally employed in such situations. Friction welding (FRW) is one such solid state welding process that can be employed in such situations. In the present investigation an experimental set-up was made in order to achieve friction welding of plastically deformed AISI 304 steels.In this experimental study austenitic stainless steel (AISI 304) was welded under different welding parameters and afterwards the mechanical properties such as tensile strength, impact strength and hardness were experimentally determined. It is the strength of welded joints, which is fundamental property to the service reliability of the weldments and hence present work was undertaken to study the influence of axial pressure and rotational speed in friction welded joints.