This article provides a brief review of the classification and characteristics of cast irons. It describes the processes used to clean iron castings, including mechanical cleaning and finishing and nonmechanical cleaning. The article discusses surface treatments used to extend casting life when resistance to corrosion, wear, and erosion is required. The common methods include electroplating, electroless plating, hardfacing, weld cladding, surface hardening, porcelain enameling, and organic coatings.

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.