The resistance welding processes commonly employed for joining aluminum are resistance spot welding, resistance seam welding, resistance roll welding, upset and flash welding for butt joining welding, and high-frequency resistance welding. This article discusses the general factors affecting resistance welding: electrical and thermal conductivities, rising temperature, plastic range, shrinkage, and surface oxide. It reviews the weldability of base materials such as Alclad alloys and aluminum metal-matrix composites. The article describes the joint design and welding procedures for resistance spot welding, as well as the joint type, equipment, and welding procedures for seam and roll spot welding. It concludes with information on flash welding, high-frequency welding, and cross-wire welding.

Weldability is a function of three major factors: base material quality, welding process, and design. This article focuses on base-metal weldability of aluminum alloys in terms of mechanical property degradation in both the weld region and heat-affected zone, weld porosity, and susceptibility to solidification cracking and liquation cracking. It provides an overview on welding processes, including gas metal arc welding, gas tungsten arc welding, resistance spot and seam welding, laser beam welding, and various solid-state welding processes. A review on joint design is also included, mainly in the general factors associated with service weldability (fitness). The article also provides a discussion on the selection and weldability of non-heat-treatable aluminum alloys, heat treatable aluminum alloys, aluminum-lithium alloys, and aluminum metal-matrix composites.

Quenching and partitioning (Q&P) steel is a term used to describe a series of C-Si-Mn, C-Si-Mn-Al, or other steels subjected to the quenching and partitioning heat treatment process. This article discusses the Q&P steel's chemical compositions and mechanical properties, and provides an overview of the important background and product characteristics with a focus on the automotive sheet steel application. It schematically represents the continuous annealing process, consequent phase-transformation behaviors, and forming-limit curves of Q&P steels. The article describes the parameters associated with resistance spot welding, laser welding, and metal active gas welding. It also provides useful information of retained austenite volume fraction measured by x-ray diffraction and electron backscatter diffraction. The article also examines microstructure evolution during tensile testing at different strain levels using electron backscatter diffraction.

Microjoining methods are commonly used to fabricate medical components and devices. This article describes key challenges involved during microjoining of medical device components. The primary mechanisms used in microjoining for medical device applications include microresistance spot welding (MRSW) and laser welding. The article illustrates the fundamental principles involved in MRSW and laser welding. The article presents examples of various microjoining methods used in medical device applications, including pacemaker and nitinol microscopic forceps.

Resistance welding (RW) encompasses many variations on the basic theme of local Joule heating while an external pressure is applied. This article provides an overview of the most generally applied RW processes, followed by a discussion on the general design aspects of various resistance-welded joints. The various resistance-welded joints include spot welds, projection welds, seam welds, and butt welds. The article explains the relative contributions of the Joule, Peltier, and Thomson effects for typical RW scenarios. It concludes with information on the electrode “follow” behavior.

Ultrasonic metal welding is a solid-state welding process that produces coalescence through the simultaneous application of localized high-frequency vibratory energy and moderate clamping forces. This article discusses the parameters to be considered when selecting a suitable welder for ultrasonic metal welding. It details the personnel requirements, advantages, limitations, and applications, namely, wire welds, spot welds, continuous seam welds, and microelectronic welds of ultrasonic metal welding.

This article outlines a general approach to develop a coupled electrical-thermal-mechanical analysis for the resistance spot welding process. It provides information on the discretization of sheet-electrode geometry and distribution of contact resistivity along the sheet-sheet and electrode-sheet interfaces. The distribution can be estimated based on the discretized geometry used for the numerical modeling. The article also details the results obtained from this modeling.

Resistance spot welding (RSW) is the most widely used joining technique for the assembly of sheet metal products. This article discusses the process description, evaluation methods, and applications of RSW. It describes the equipment needed for RSW and explicates the major functions of electrodes in RSW and effect of surface condition on the technique. The article concludes with information on the safety precautions to be followed during the welding process.

This article presents the structural attributes and internal characteristics of spot welds as well as the commonly inspected imperfections in resistance welds. It describes the industrial requirements for weld quality. Commonly performed destructive evaluations, namely, manual testing, quasi-static mechanical tests, dynamic mechanical tests, and metallographic examination, are reviewed. The article reviews weld-quality monitoring using various process signals and provides a discussion on the on-line and off-line nondestructive evaluation methods of spot weld quality.

This article describes the significance of the three variables that affect the resistance spot welding process: welding current, electrode force, and welding time. It presents the effects of weld spacing and surface preparation on weld quality. The article elaborates the typical sequence of steps for determining the satisfactory conditions for spot welding and the mechanical aspects that affect this process. It considers the effects of process variables on the weld lobe. The article reviews surface preparation, part fit-up, electrode drives, weld parameters, and tests associated with seam welding. It concludes with a discussion on the welding equipment and other factors associated with resistance spot and seam welding.

This article presents a detailed account of the welding parameters, equipment needed, applications, advantages, limitations, and the process variables affecting various types of resistance welding operations, namely, resistance spot welding, resistance seam welding, resistance projection welding, and flash welding.

Resistance spot welding (RSW) is a process in which faying surfaces are joined in one or more spots by the heat generated by resistance to the flow of electric current through workpieces that are held together under force by electrodes. This article discusses the major advantages of spot welding and the three principal elements, such as electrical circuit, control circuit, and mechanical system, of RSW machines. It reviews the three basic types of RSW machines: pedestal-type welding machines, portable welding guns, and multiple spot welding machines. The article provides information on weldabilily of uncoated steels and zinc-coated steels, as well as aluminum alloys.

Zirconium and its alloys are available in two general categories: commercial grade and reactor grade. This article discusses the welding processes that can be used for welding any of the zirconium alloys. These include gas-tungsten arc welding (GTAW), gas-metal arc welding (GMAW), plasma arc welding (PAW), electron-beam welding (EBW), laser-beam welding (LBW), friction welding (FRW), resistance welding (RW), resistance spot welding (RSW), and resistance seam welding (RSEW). The article reviews the selection of shielding gases and filler metals for welding zirconium alloys. It concludes with a discussion on process procedures for welding zirconium alloys.

Resistance welding (RW) encompasses a group of processes in which the heat for welding is generated by the resistance to the flow of electrical current through the parts being joined. The three major resistance welding processes are resistance spot welding (RSW), resistance seam welding (RSEW), and projection welding (PW). This article addresses the considerations for using these processes to join specific types of materials. It discusses the process variations, applicability, advantages, and limitations of these resistance welding processes. The article provides information on flash welding, high-frequency resistance welding, and capacitor discharge stud welding. It concludes with a discussion on resistance welding of stainless steels, aluminum alloys, and copper and copper alloys.

Resistance seam welding (RSEW) is a process in which the heat generated by resistance to the flow of electric current in the work metal is combined with pressure to produce a welded seam. This article discusses the various classes of the RSEW process, namely roll spot welding, reinforced roll spot welding, and leak-tight seam welding. It provides information on the applications of lap seam weld, mash seam weld, and butt seam weld. The article reviews the advantages and limitations of seam welding compared to resistance spot welding, projection welding, and laser welding. It describes the four basic types of resistance seam weld machines: circular, longitudinal, universal, and portable. The article concludes with a discussion on weld quality and process control for seam welding.

This article begins with a discussion on the advantages and limitation of ultrasonic welding (USW). It describes variations of the USW process which can produce different weld geometries. These variations are helpful in producing spot welds, line welds, continuous seam welds, ring welds, and microelectronic welds. The article provides information on the functions of USW personnel and describes the special conditions in USW which include the condition of the surface, the use of an interlayer, and the control of resonance. It concludes with a description on the weld quality, the influencing factors, surface appearance and deformation, and metallographic examination.

This article briefly reviews the physical phenomena that influence the input-energy distribution. It discusses the several simplified and detailed heat source models used in the modeling of arc welding, high-energy-density welding, and resistance welding processes.