This article discusses the susceptibility of carbon steels to hydrogen-induced cracking, solidification cracking, lamellar tearing, weld metal porosity, and heat-affected zone (HAZ) mechanical property variations. The composition and mechanical properties of selected carbon steels used in arc welding applications are listed in a table. The article presents process selection guidelines for arc welding carbon steels. It provides information on the shielded metal arc welding, gas-metal arc welding, and flux-cored arc welding, gas-tungsten arc and plasma arc welding, submerged arc welding, electrogas welding, electroslag welding, and stud arc welding.

This article discusses the metallurgical aspects of underwater welds. It describes the microstructural development, which mainly includes three types of ferrite associated with low carbon steel weld metal: grain-boundary ferrite, sideplate ferrite, and acicular ferrite. The article explains the factors that affect heat-affected zone (HAZ) cracking. These include hydrogen from the weld pool, microstructures that develop in the HAZ, and stress levels that develop in the weld joint. The article describes the welding practices that can reduce residual stresses. It explains the effect of water pressure on the formation of porosity in underwater gravity welding. The article concludes with a discussion on the practical applications of underwater welding.

This article is a guide to the welding of commercially available aluminum-lithium alloys. It discusses the weldability issues created by weld porosity, hot cracking, and filler metal selection and presents the data revealed from weld characterization.