Search Results for hardenability selection charts

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.

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.

Properties of an engineering material have a characteristic range of values that are conveniently displayed on materials selection charts. This article describes the plotting of data on these charts. It discusses the features of various types of material property charts, namely, modulus-density, strength-density, fracture toughness-density, modulus-strength, specific stiffness-specific strength, fracture toughness-modulus, fracture toughness-strength, loss coefficient-modulus, thermal conductivity-thermal diffusivity, thermal expansion-thermal conductivity, thermal expansion-modulus, and normalized strength-thermal expansion charts. The article examines the use of material property charts in presenting information in a compact and easily accessible manner.

This article provides useful information on the selection of steels for heat treatment in order to achieve the required hardness. It discusses the effects of alloying elements on hardenability using the Grossmann's concept, and presents a discussion on the effects of alloying elements in hot-worked and cold-drawn steels. The article focuses on the selection of carbon and alloy steels based on the function of the alloying elements, and discusses the specific effects of alloying elements in steel in a tabulated form. The depth and degree of hardening (percentage of martensite) are dictated by the engineering stress analysis. Mechanical properties of quenched and tempered steels develop similar tensile properties for all practical purposes for all compositions with the same hardness. The article also provides information on the selection of steels to meet the required hardness, and elucidates the concept of hardenability for wear resistance with the help of graphs.

Bearing steels, which include high-carbon and low-carbon types, can be divided into service-based classes, such as normal service, high-temperature service, and service under corrosive conditions. This article discusses the importance of matching the hardenability and quenching of a bearing steel. It also discusses the typical microstructure of a high-carbon through-hardened bearing, and shows typical case and core microstructures in carburized bearing materials. Apart from a satisfactory microstructure, which is obtained through the proper combination of steel grade and heat treatment, the single most important factor in achieving high levels of rolling-contact fatigue life in bearings is the cleanliness, or freedom from harmful nonmetallic inclusions, of the steel. Alloy conservation and a more consistent heat-treating response are benefits of using specially designed bearing steels. The selection of a carburizing steel for a specific bearing section is based on the heat-treating practice of the producer, either direct quenching from carburizing or reheating for quenching, and on the characteristics of the quenching equipment.

This article is a comprehensive collection of summary charts that provide data and information that are helpful in considering and selecting applicable processes alternative to the conventional material-removal processes. Process summary charts are provided for electrochemical machining, electrical discharge machining, chemical machining, abrasive jet machining, laser beam machining, electron beam machining, ultrasonic impact grinding, hydrodynamic machining, thermochemical machining, abrasive flow machining, and electrical discharge wire cutting.

This article reviews the most common reasons for failures and the purpose of a failure investigation. It discusses the nine steps for the organization of a good failure investigation. The three basic tools that are helpful in any failure investigation, namely, a fault tree, a failure mode assessment chart, and a technical plan for resolution chart, are reviewed. The article briefly describes failure investigation pitfalls and concludes with information on the other common tools used for failure investigation and root cause determination.

Rolling-element bearings, whether ball bearings or roller bearings with spherical, straight, or tapered rollers, are fabricated from a wide variety of steels. This article discusses the production process, characteristics, nominal compositions, and types of bearing steels. These include standard bearing steels, such as high-carbon bearing steels and carburizing bearing steels; and special-purpose bearing steels, such as high-temperature service bearing steels and corrosion-resistant bearing steels.

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 defines performance indices in a formal way and specifies how they are derived. The performance indices for a light, strong tie and a light, stiff beam are presented. The article presents two case studies that illustrate the use of material indices, shape factors, and selection charts to select materials.

Mathematical models have been used for over five decades in industrial heat-treating operations. Most of these modeling efforts have emanated from academia or research institutes, with the primary approach of mathematically capturing heat-treating processes and validating quality predictions. In this article, a contrarian but more realistic scenario is considered, where two industrial problem descriptions become the starting point. The technical complexity of the industry problem has been elaborated for a deeper understanding of the issue along with elaboration of the approach and potential methods for determining a solution. Then, quantitative analyses of practical industrial problems are demonstrated. Finally, the potential shift in these approaches with the advent of Industry 4.0 is outlined.

Statistics are extremely important tools in the operation of press shops, providing numerical process analysis capabilities. The most common use of statistics in the press shop is statistical process control (SPC) that uses statistical techniques such as control charts to analyze a process or its output to enable appropriate actions to be taken to achieve and maintain a state of statistical control. This article discusses the role of statistics in sheet metal forming operations, both in terms of SPC techniques, such as control charting, statistical deformation control, and experimental design, including single-variable studies, multivariable studies, and Taguchi experiments.

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.

Tempering of steel is a process in which hardened or normalized steel is heated to a temperature below the lower critical temperature and cooled at a suitable rate, primarily to increase ductility, toughness, and grain size of the matrix. This article provides an overview of the variables that affect the microstructure and mechanical properties of tempered steel, namely, the tempering temperature, tempering time, carbon content, alloy content, and residual elements. Tempering after hardening is performed to relieve quenching stresses and ensure dimensional stability of steel. The article discusses the embrittlement problems associated with tempering. Four types of equipment are used for tempering, namely, convection furnaces, salt bath furnaces, oil bath equipment and molten metal baths. Special procedures for tempering are briefly reviewed.

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.

This article discusses the key factors that influence the selection of engineered materials for a particular application. Materials properties such as ultimate tensile strength, yield strength, hardness, and ductility, which chiefly define the performance or functional characteristics, are covered. This is followed by manufacturing process considerations such as material factors, shape factors, process factors, and the characteristics of fabricability, namely formability, workability, castability, machinability, and weldability.

This article discusses the organization required at the outset of a failure investigation and provides a methodology with some organizational tools. It focuses on the use of problem-solving tools such as a fault tree analysis combined with critical thinking. The discussion covers nine steps to organize a good failure investigation. They are as follows: understand and negotiate goals of the investigation, obtain a clear understanding of the failure, identify all possible root causes, objectively evaluate the likelihood of each root cause, converge on the most likely root cause(s), objectively and clearly identify all possible corrective actions, objectively evaluate each corrective action, select optimal corrective action(s), and evaluate effectiveness of selected corrective action(s). Common problems detrimental to a failure investigation are also covered.

This article reviews the factors that have a significant effect on the selection and interpretation of results of different hardness tests, namely, Brinell, Rockwell, Vickers, and Knoop tests. The factors concerned include hardness level (and scale limitations), specimen thickness, size and shape of the workpiece, specimen surface flatness and surface condition, and indent location. The article focuses on the selection for specific types of materials, such as steels, cast irons, nonferrous alloys, and plastics, and industrial applications, of hardness tests.