Air hardening steel is a type of steel that has deep hardenability and can be hardened in large sections by air cooling. This article discusses the principles of heat treatment of air-hardening steel, and describes the recommended heat treating practices for air-hardening high-strength structural steels, namely, H11 Mod, H13 steel, 300M steel, D-6A and D-6AC, and AF1410 steel. It also provides information on recommended heat treating practices for air-hardening martensitic stainless steels.

Electroslag welding (ESW) involves high energy input relative to other welding processes, resulting generally in inferior mechanical properties and specifically in lower toughness of the heat-affected zone. Electrogas welding (EGW) is a method of gas metal or flux cored arc welding, wherein an external gas is supplied to shield the arc, and molding shoes are used to confine the molten weld metal for vertical-position welding. This article describes the fundamentals, temperature relations, consumables, metallurgical and chemical reactions, and process development of ESW. The problems, quality control, and process applications of ESW and EGW are also discussed.

Ultrahigh-strength steels are designed to be used in structural applications where very high loads are applied and often high strength-to-weight ratios are required. This article discusses the composition, mechanical properties, processing, product forms, and applications of commercial structural steels capable of a minimum yield strength of 1380 MPa (200 ksi). These include medium-carbon low-alloy steels, such as 4340, 300M, D-6a and D-6ac steels; medium-alloy air-hardening steels, such as HI1 modified steel and H13 steel; high fracture toughness steels, such as HP-9-4-30, AF1410, and AerMet 100 steels; and maraging steels.

This article provides information on fracture toughness and fatigue crack growth of structural steels. It describes fatigue life behavior in terms of unnotched fatigue limits, notch effects, axial strain-life fatigue, and mean stress effects. The article analyzes the mechanisms of corrosion fatigue crack initiation and prevention of corrosion fatigue. It presents case histories of fatigue failure of various steel components. The article reviews the failure of coiled tubing in a drilling application and the failure of coiled tubing due to hydrogen sulfide exposure, with examples.

Painting is a generic term for the application of a thin organic coating to the surface of a material for decorative, protective, or functional purposes. This article provides a detailed account of the types and selection factors of paints and the various application methods, including conventional air atomized, airless, and electrostatic spray; roller coating; dip coating; flow coating; curtain coating; tumble coating; electrocoating; and powder coating. Surface preparation methods and prepaint treatments for coating systems are also discussed. The article includes information on quality control procedures, causes of paint film defects, cost calculation, and safety and environmental precautions. The composition and characteristics of organic coatings, coating system selection factors, the types of paints for structural steel, and the applications of paint on structural steel are also reviewed.

This article discusses factors involved in selecting welding processes and consumables and establishing procedures and practices for the arc welding of low-alloy steels. It provides information on welding consumables in terms of filler metals and fluxes and shielding gases. The article describes the various categories of low-alloy steels, such as high-strength low-alloy (HSLA) structural steels, high-strength low-alloy quenched and tempered(HSLA Q&T) structural steels, low-alloy steels for pressure vessels and piping, medium-carbon heat-treatable (quenched and tempered) low-alloy (HTLA) steels, ultrahigh-strength low-alloy steels, and low-alloy tool and die steels. It concludes with a discussion on repair practices for tools and dies.

Critical structural components must be fabricated from steels that exhibit adequate low-temperature fracture toughness because of the serious consequences of failure due to brittle fracture. This article reviews fracture resistance assessment procedures for welded joints and includes discussions on fatigue crack growth and fracture toughness. It presents the fracture toughness requirements specified by different design codes, summarizes the specifications for offshore structural steels provided by international standards organizations, and discusses the applications of these specifications. The article also focuses on advances made in steel technology and the impact of these advances on the fracture toughness of steel.

This article considers four types of high-strength structural steels: heat-treated low-alloy steels, as-rolled carbon-manganese steels, heat-treated (normalized or quenched and tempered) carbon steels, and as-rolled high-strength low-alloy (HSLA) steels (which are also known as microalloyed steels). The article places emphasis on HSLA steels, which are an attractive alternative in structural applications because of their competitive price per-yield strength ratios. HSLA steels are primarily hot-rolled into the usual wrought product forms and are furnished in the as-hot-rolled condition. In addition to hot-rolled products, HSLA steels are also furnished as cold-rolled sheet and forgings. This article describes the different categories of HSLA steels and provides a summary of characteristics and intended uses of HSLA steels described in the American Society for Testing and Materials (ASTM) specifications. The article also presents some applications of HSLA steels.