Hardfacing is a form of surfacing that is applied for the purpose of reducing wear, abrasion, impact, erosion, galling, or cavitation. This article describes the deposition of hardfacing alloys by oxyfuel welding, various arc welding methods, laser welding, and thermal spray processes. It discusses the categories of hardfacing alloy, such as build-up alloys, metal-to-metal wear alloys, metal-to-earth abrasion alloys, tungsten carbides, and nonferrous alloys. A summary of the selection guide for hardfacing alloys is presented in a table. The article describes the procedures for stainless steel weld cladding and the factors influencing joint integrity in dissimilar metal joining. It concludes with a discussion on joining carbon and low-alloy steels to various dissimilar materials (both ferrous and nonferrous) by arc welding.

This article describes two methods based on rolling of sheet. The first is roll welding, where two or more sheets or plates are stacked together and then passed through rolls until sufficient deformation has occurred to produce solid-state welds. The other is laser roll welding, which is a hybrid process based on a thin-melting interface for a lap joint of dissimilar-metal sheets using a roller and one-sided laser heating. The article discusses the types, advantages, and applications of roll welding and laser roll welding. It also provides a detailed discussion on the laser roll welding of dissimilar metals.

Ultrasonic welding (USW) is effectively used to join both similar and dissimilar metals with lap-joint welds. This article describes procedure considerations for the ultrasonic welding of specific material types. It reviews difficult-to-weld alloys, such as carbon and low-alloy steels, high-strength steels, and stainless steel, and provides information on the applications of weldable alloys such as aluminum alloys and copper alloys. The article concludes with a discussion on welding of dissimilar metal (nonferrous-to-nonferrous) combinations and its applications.

Dissimilar metal welding applications require careful control over the welding parameters and corresponding dilution level in order to produce welds with proper microstructure and properties for the intended service. This article reviews the relation between the dilution and bulk fusion-zone compositions and describes the effect of fusion welding parameters on dilution. It also provides typical examples of the microstructure and property control in dissimilar weld applications.

In a typical semiconductor integrated circuits (SICs) component, corrosion may be observed at the chip level and at the termination area of the lead frames that are plated with a solderable metal or alloy, such as tin and tin-lead alloys that are susceptible to corrosion. This article focuses on the key factors contributing to corrosion of electronic components, namely, chemicals (salts containing halides, sulfides, acids, and alkalis), temperature, air (polluted air), moisture, contact between dissimilar metals in a wet condition, applied potential differences, and stress. It discusses the chip corrosion and oxidation of tin and tin-lead alloys (solders) in SIC. The article also addresses the corrosion of the device terminations resulting in lead (termination) tarnishing that are caused by various factors, including galvanic corrosion, chemical residues, base metal migration and plating additives.

This article provides an in-depth review of thermocouples and the metals from which they are made. It explains how dissimilar metal conductors in contact at opposite ends can generate an electromotive force if the junctions are heated or cooled to different temperatures. The article discusses thermocouple circuits and instrumentation, calibration methods, insulation requirements, operating ranges, measurement errors, and maintenance procedures. It also provides property data and emf curves for common metals and thermocouple types, and contains information on color coding used around the world.

Electron-beam welding (EBW) can produce deep, narrow, and almost parallel-sided welds with low total heat input and relatively narrow heat-affected zones in a wide variety of common and exotic metals. This article discusses the joint configurations and shrinkage stresses encountered in various joint designs for electron-beam welding, as well as special joints and welds including multiple-pass welds, tangent-tube welds, three-piece welds, and multiple-tier welds. It provides a comparison of medium vacuum EBW with high-vacuum EBW. Scanning is a method of checking the run-out between the beam spot and the joint to be welded. The article describes various scanning techniques for welding dissimilar metals and provides information on the application of electron-beam wire-feed process for repairs. It concludes with a discussion on EBW of heat-resistant alloys, refractory metals, aluminum alloys, titanium alloys, copper and copper alloys, magnesium alloys, and beryllium.

Cast irons and carbon steels are brazeable materials, although the brazeability of cast iron is lower than that of carbon steel. The article provides a detailed discussion on the brazeability of different types of cast iron (malleable iron, ductile iron, and gray iron), carbon steels, and dissimilar metals. It describes the factors considered in the selection of filler-metal for cast iron and carbon steel brazing, such as temperature and environment, brazed joint design, heat source, and heat-treatment requirements. The article also discusses the basic considerations in cleaning and fixturing procedures, filler metal and flux/atmosphere feeding procedures, and the heating methods of cast iron and carbon steel brazing.