Hardening and depth of hardening of steel is a critically important material and process design parameter. This article presents a selective overview of experimental and predictive procedures to determine steel hardenability. It also covers the breadth of steel hardenability, ranging from shallow, to very difficult to harden, to air-hardening steels.

This article is a comprehensive collection of graphs that present information on the hardenability bands of various grades of alloy steels. It also includes figures showing correlations of Jominy equivalent cooling rates, plots of end-quench bands of carbon steels, and logarithmic plots of relative hardenability of carbon steels.

Hardenability of steel depends on carbon content and other alloying elements as well as on the grain size of the austenite phase. This article provides information on the calculation of high-carbon (carburized) steel hardenability. It contains tables that list multiplying factors that are used for the calculation of case hardenability of carburizing steels and the hardenability of high-carbon steels hardened after a prior normalize or quench treatment. The article reviews the derivation and limitations of multiplying factors.

Hardenability is a composition-dependent property of steel and depends on carbon content and other alloying elements as well as the grain size of the austenite phase. This article provides an overview of a wide range of testing procedures used to determine and quantify hardenability of shallow-hardening, low-carbon, plain carbon, and low-alloy medium-carbon steels ranging from classical fracture and etching, Grossmann hardenability, and Jominy end-quench testing to manual and computerized computational methods. The article then uses this as a backdrop for the implementation of the core concepts of hardenability in a variety of predictive tools for calculating hardenability. The Caterpillar 1E0024 Hardenability Calculator, a personal computer-based program, calculates the Jominy curve based on the steel composition. The article also describes the method for boron and nonboron steels, with calculation examples for 8645 steel and 86B45 steel.

Hardenability refers to the ability of steel to obtain satisfactory hardening to some desired depth when cooled under prescribed conditions. It is governed almost entirely by the chemical composition (carbon and alloy content) at the austenitizing temperature and the austenite grain size at the moment of quenching. This article describes the Jominy end-quench test, the Grossman method, and the air hardenability test to evaluate hardenability. It also reviews the factors that influence steel hardenability and selection.

Hardenability is usually the single most important factor in the selection of steel for heat-treated parts. The hardenability of steel is best assessed by studying the hardening response of the steel to cooling in a standardized configuration in which a variety of cooling rates can be easily and consistently reproduced from one test to another. These include the Jominy end-quench test, the carburized hardenability test, and the surface-area-center hardenability test. This article discusses the effects of varying carbon content as well as the influence of different alloying elements on hardenability of steels. The basic information needed before a steel with adequate hardenability can be specified as the as-quenched hardness required prior to tempering to final hardness that will produce the best stress-resisting microstructure; the depth below the surface to which this hardness must extend; and the quenching medium that should be used in hardening.

This article presents hardenability curves for more than 80 types of carbon and alloy hardenability band (H-band) steels. Each H-band hardenability limit curve is presented graphically and in tabular form, in both metric and English units. The caption for each curve includes the normalizing and austenitizing heat-treating temperatures recommended by SAE for these steels. The article includes a brief description of how hardenability curves are used for specification purposes.

Hardenability of steel is the property that determines the depth and distribution of hardness induced by quenching. Hardenability is usually the single most important factor in the selection of steel for heat-treated parts. The hardenability of a steel is best assessed by studying the hardening response of the steel to cooling in a standardized configuration in which a variety of cooling rates can be easily and consistently reproduced from one test to another. These include the Jominy end-quench test, the carburized hardenability test, and the air hardenability test. Tests that are more suited to very low hardenability steels include the hot-brine test and the surface-area-center test. The article discusses the effects of varying carbon content as well as the influence of different alloying elements. It includes charts and a table that serve as a general steel hardenability selection guide.

Hardenability is an expression of the propensity of steel to harden when quenched at the austenitizing temperature. It is defined in terms of the depth and distribution of alloying elements present in the steel. This article describes the selection process for steel with an emphasis on hardenability. It explains the significance of H-steels, and how they are guaranteed to meet established hardenability limits for specific temperatures and chemical compositions. The article compares hardenability curves for six series of steel and includes several charts showing composition and H-band limits for various alloy grades.