The main focused aim of developing new processing and manufacturing technologies are to reduce production or manufacturing costs, processing times, and to enhance manufactured product properties. The developed processing techniques should be widely acceptable for all types of materials including metal matrix composites, ceramics, alloys, and fiber reinforced plastics. Microwave materials processing is emerging as a novel processing technology which is applicable to a wide variety of materials system including processing of MMC, FRP, alloys, ceramics, metals, powder metallurgy, material joining, coatings, and claddings. In comparison to the conventional processes, microwave processing of materials offers better mechanical properties with reduced defects and economical advantages in terms of power and time savings. The present review work focuses mainly on global developments taking place in the field of microwave processing of materials and their relevant industrial applications.

Microwave Processing of Materials and Applications in Manufacturing Industries: A Review

Friction welding is now well established as a means of joining many different types of materials, because it has proved itself to be a reliable and economical way of producing high quality welds. The present paper introduces different friction welding processes, their advantages and shortcomings. The history of friction welding and typical applications are also reviewed. In the context of friction welding, a number of subjects, such as frictional behaviour, joining mechanism, interface temperature and heat generation, still exist, where different concepts for explanation of the physical mechanisms have been proposed by different investigators. To clarify some inconsistencies in the interpretation of the friction welding process, a thorough review and critical assessment of the literature associated with this process is attempted.

Friction welding – critical assessment of literature

Dissimilar metal friction welding of austenitic–ferritic stainless steels

Friction welding (FW) is a high quality, nominally solid-state joining process, which produces welds of high structural integrity. Rotary friction welding (RFW) is the most commonly used form of FW, while linear friction welding (LFW) is a relatively new method being used mainly for the production of integrally bladed disc (blisk) assemblies in the aircraft engine industry. Numerous similar and dissimilar joints of structural metallic materials have been welded with RFW and LFW. In this review, the current state of understanding and development of RFW and LFW is presented. Particular emphasis is placed on the process parameters, joint microstructure, residual stresses, mechanical properties and their relationships. Finally, opportunities for further research and development of the RFW and LFW processes are identified.

Linear and rotary friction welding review

Friction welding is now well established as one of the most economical and highly productive methods in joining similar and dissimilar metals. It is widely used in automotive and aerospace industrial applications. Friction welding is often the only viable alternative in this field to overcome the difficulties encountered in joining the materials with widely varying physical characteristics. This process employs a machine that is designed to convert mechanical energy into heat at the joint to weld using relative movement between workpieces, without the use of electrical energy or heat from other sources. This review deals with the fundamental understanding of the process. The focus is on the mechanism of friction welding, types of relative motions of the process, influence of parameters, heat generation in the process, understanding the deformation, microstructure and the properties of similar and dissimilar welded materials.

Advances in friction welding process: a review

Dissimilar metal welding of austenitic (AISI 304)-ferritic (AISI 430) stainless steel has been taken up to understand the influence of the welding process on microstructure and mechanical properties. Fusion welding processes, namely, gas tungsten arc welding (GTAW), electron beam welding (EBW), and friction welding, have been employed. The GTAW and EBW processes were selected to understand the heat input effects, while friction welding was included to compare fusion and solid-state welding processes. The material used for fusion welding studies is 20-mm-thick, hot-rolled, and annealed plate. Rods of 18 mm diameter machined from the same plate material were used for friction welding studies. In GTAW, ER 430 filler material was employed for dissimilar metal combination, while other welds are autogenous. Gas tungsten arc welds consisted of coarse columnar grains. In electron beam welds, the microstructure consisted of predominantely equiaxed grains on the austenitic stainless steel side, while colum...

Influence of welding processes on microstructure and mechanical properties of dissimilar austenitic-ferritic stainless steel welds

Friction drilling is a non traditional hole making process in which a conical rotating tool is applied to penetrate into workpiece and create the hole in a single step, without generating chips. The process relies on the heat generated due to the frictional force between tool and workpiece, to soften, penetrate and deform the work material into a bushing shape. The mechanical aspects of friction drilling are investigated in this paper. Aluminum (AA6351) is taken as work material and friction drilling is carried out by high speed steel conical tool. Mathematical models are developed in this work for axial thrust and torque. Proper experimental layout is designed and Taguchi Method is applied to evaluate the performance of high speed steel friction drill on AA6351 workpiece of thickness 1mm.

Some investigations in friction drilling aa6351 using high speed steel tools

An attempt has been made to study the friction welding characteristics of an austenitic stainless steel AISI 304 employing a continuous drive friction welding machine. The central region in some of the welds exhibited abnormal grain growth. Optimization studies revealed that the optimum parameters depend on the property of interest. In general, friction welds exhibited lower notch tensile strength and impact toughness than the parent metal due to aligned microstructure features. An inverse relationship has been observed between notch tensile strength and impact toughness.

Continuous Drive Friction Welding Studies on AISI 304 Austenitic Stainless Steel Welds

An attempt has been made to study the continuous drive friction welding characteristics of AISI 430 ferritic stainless steel. All the welds exhibited fine equiaxed ferritic grains. Parameters that result in marginally coarse grain size in the bond zone led to low hardness and high toughness. Welds having a fine grain size exhibited higher hardness and superior notch tensile strength. An inverse relationship was observed between impact toughness and notch tensile strength. Regression analysis of the data revealed a high degree of correlation. It was concluded that the selection of parameters would depend on the property of interest.

V. V. Satyanarayana

Papers

Dissimilar metal friction welding of austenitic–ferritic stainless steels

Influence of welding processes on microstructure and mechanical properties of dissimilar austenitic-ferritic stainless steel welds

Some investigations in friction drilling aa6351 using high speed steel tools

Continuous Drive Friction Welding Studies on AISI 304 Austenitic Stainless Steel Welds

Continuous drive friction welding studies on AISI 430 ferritic stainless steel