Carbon arc welding (CAW) utilizes a nonconsumable electrode, made of carbon or graphite, to establish an arc between itself and either a workpiece or another carbon electrode. This article describes the operation modes of the CAW process: single-electrode operation and twin-electrode operation. It presents a schematic representation of typical arrangements for single-electrode and twin-electrode carbon arc welding. Recommended current ranges for carbon and graphite electrodes are listed in a table. The article concludes with information on the applications of the CAW process.

Plasma arc welding (PAW) can be defined as a gas-shielded arc welding process where the coalescence of metals is achieved via the heat transferred by an arc that is created between a tungsten electrode and a workpiece. This article focuses on the operating principles and procedures, current and operating modes, advantages, disadvantages, and applications of PAW. It discusses the personnel and equipment requirements, as well as the joints used in the process. The power source, plasma control console, water cooler, welding torch, and gas supply system for the plasma and shielding gases are also reviewed.

Plasma arc welding (PAW) can be defined as a gas-shielded arc welding process where the coalescence of metals is achieved via the heat transferred by an arc that is created between a tungsten electrode and a workpiece. This article discusses the melt-in mode and the keyhole mode of the PAW process, as well as the advantages and disadvantages. It describes the components of a basic PAW system, namely the power source, plasma control console, water cooler, welding torch, and gas supply system for the plasma and shielding gases. The article provides information on the applications of the PAW process and discusses the typical components and joints used. It concludes with information on personnel requirements and safety issues.

Plasma-metal inert gas (MIG) welding can be defined as a combination of plasma arc welding (PAW) and gas-metal arc welding (GMAW) within a single torch, where a filler wire is fed through the plasma nozzle orifice. This article describes the principles of operation and operating modes of plasma-MIG welding. It discusses the advantages and disadvantages of the plasma-MIG process. The article describes the components, including power sources and welding torches, of equipment used for the plasma-MIG process. It provides information on inspection and weld quality control and troubleshooting techniques. The article concludes with a discussion on the applications of the plasma-MIG process.

This article describes the characteristics and technology of power sources for major arc welding methods along with the suggested criteria for assuring that a power source selection can safely deliver the desired output and yield long service life. Power sources with single-phase AC input voltage, three-phase input machines, inverter-based power sources, short arc gas metal arc welding power sources, and multiple arc power sources are discussed. The article also presents the factors to be considered when selecting a power source.

Plasma gas metal arc welding (GMAW) is a process that can be defined as a combination of plasma arc welding (PAW) and GMAW within a single torch, where a filler wire is fed through the plasma nozzle orifice. Although originally referred to as plasma-MIG welding, the preferred term is plasma-GMAW. This article provides a detailed discussion on the operating procedures, advantages, disadvantages, and applications of GMAW and describes the equipment used in the plasma-GMAW.

Power sources are apparatuses that are used to supply current and voltages that are suitable for particular welding processes. This article describes power sources for arc welding, resistance welding, and electron-beam welding. The more-common welding processes that use constant-current and constant-voltage power sources are listed in a table. The article describes the open-circuit voltage characteristics and power source control methods. The control methods employ either pulse width modulation (PWM) or frequency modulation (FM).

This article provides an overview of the components of a resistance welding machine. It focuses on the single-phase control system and medium-frequency direct current system of resistance welding. The article also includes information on their feedback systems, rectification systems, and power sources.