This article describes the principal methods for macroindentation hardness testing by the Brinell, Vickers, and Rockwell methods. For each method, the test types and indenters, scale limitations, testing machines, calibration, indenter selection and geometry, load selection and impression size, testing methodology, and testing of specific materials are also discussed.

Hardness testing is perhaps the simplest and the least expensive method of mechanically characterizing a material. This article provides an overview of the principles of hardness testing. It compares Brinell with Meyer hardness testing and hardness testing of fully cold worked metals with fully annealed metals. The article discusses the plastic deformation of ideal plastic metals under an indenter, by a flat punch, and by spherical indenters. The classification of the hardness tests using various criteria, including type of measurement, magnitude of indentation load, and nature of the test, is also provided.

Mechanical testing is an evaluative tool used by the failure analyst to collect data regarding the macro- and micromechanical properties of the materials being examined. This article provides information on a few important considerations regarding mechanical testing that the failure analyst must keep in mind. These considerations include the test location and orientation, the use of raw material certifications, the certifications potentially not representing the hardware, and the determination of valid test results. The article introduces the concepts of various mechanical testing techniques and discusses the advantages and limitations of each technique when used in failure analysis. The focus is on various types of static load testing, hardness testing, and impact testing. The testing types covered include uniaxial tension testing, uniaxial compression testing, bend testing, hardness testing, macroindentation hardness, microindentation hardness, and the impact toughness test.

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.

A newly developed theory on plasticity makes it possible to include elastic effects, which play a major role when using blunt hardness indenters. This article reviews the new theory and explains several phenomena associated with practical hardness testing. In the indentation hardness test, a blunt indenter that approximates a flat punch is forced into a plane surface. The effective cone angle for most indenters is such that some upward flow results even when there is sufficient material surrounding the indenter to provide a full elastic constraint. When loaded by a blunt indenter, materials with high values of Young's Modulus of Elasticity/uniaxial flow stress (E/Y) (metals) appear to develop a Hertzian stress distribution over the contact. In contrast, materials with low values of E/Y (glasses and polymers) develop a uniform distribution of stress.

Hardness conversions are empirical relationships that are defined by conversion tables limited to specific categories of materials. This article tabulates examples of the published hardness conversion equations for various materials including steels, cement carbides, and white cast irons. It informs that when making hardness correlations, it is best to consult ASTM E 140. The article tabulates the approximate Rockwell B hardness and Rockwell C hardness conversion numbers for nonaustenitic steels according to ASTM E 140. It also tabulates the approximate equivalent hardness numbers for Brinell hardness numbers and Vickers (diamond pyramid) hardness numbers for steel.

Hardness conversions are empirical relationships that are defined by conversion tables limited to specific categories of materials. This article summarizes hardness conversion formulas for various materials in a table. It tabulates the approximate Rockwell B and Rockwell C hardness conversion numbers for nonaustenitic steels. The article lists the approximate equivalent hardness numbers for Brinell hardness numbers and Vickers hardness numbers for steel in tables. The tables are also outlined in a graphical form.

Hardness conversions are empirical relationships that are defined by conversion tables limited to specific categories of materials. This article is a comprehensive collection of tables that list hardness conversion formulas. Approximate Rockwell B and C hardness conversion numbers for nonaustenitic steels, and approximate equivalent hardness numbers for Brinell and Vickers (diamond pyramid) hardness numbers for steels are provided.

Hardness conversions are empirical relationships defined by conversion tables limited to specific categories of materials. This article is a collection of tables that present approximate Rockwell B hardness conversion numbers for nonaustenitic steels as per ASTM E 140 and approximate equivalent hardness numbers for the Brinell hardness and the Vickers (diamond pyramid) hardness numbers for steel.

This article reviews the various types of mechanical testing methods, including hardness testing; tension testing; compression testing; dynamic fracture testing; fracture toughness testing; fatigue life testing; fatigue crack growth testing; and creep, stress-rupture, and stress-relaxation testing. Shear testing, torsion testing, and formability testing are also discussed. The discussion of tension testing includes information about stress-strain curves and the properties described by them.

This article begins with an overview of classes and applications of gray iron. It discusses the castability of gray iron in terms of section sensitivity and fluidity. The article provides information on the dimensions of prevailing sections recommended for gray irons and reviews the properties and specifications of test bar. Properties of gray iron, such as fatigue limit, pressure tightness, impact resistance, machinability, and dimensional stability, at both room and elevated temperature, are reviewed. Wear behavior of gray iron castings during sliding contact under conditions of normal lubrication is also discussed. The article evaluates the use of alloys and heat treatment to modify as-cast properties. It concludes with information on the physical properties of gray iron castings.

Malleable iron, like ductile iron, possesses considerable ductility and toughness because of its combination of nodular graphite and low-carbon metallic matrix. There are two basic types of malleable iron: blackheart and whiteheart. This article focuses on the blackheart malleable iron and discusses the chemical composition of malleable iron. A summary of mechanical properties and specifications of malleable iron castings is presented in a table. The article also reviews the mechanical properties of ferritic malleable iron and pearlitic and martensitic-pearlitic malleable irons.

Miscellaneous hardness tests encompass a number of test methods that have been developed for specific applications. These include dynamic, or "rebound," hardness tests using a Leeb tester or a Scleroscope; static indentation tests on rubber or plastic products using the durometer or IRHD testers; scratch hardness tests; and ultrasonic microindentation testing. This article reviews the procedures, equipment, and applications associated with these alternate hardness test methods.

This article reviews the failure analysis process with specific reference to the considerations that should be addressed when a casting has failed. It describes the failure analysis methodology for three failed cast components: an aluminum bracket, a bronze suction roll, and a steel automotive spindle. The article discusses failure analysis investigation by obtaining casting background information, planning the evaluation and selecting the appropriate casting for analysis, conducting a preliminary examination, conducting the proper material evaluations, and thoroughly evaluating the test data. It concludes with information on case studies that show how the methodology is adapted for differing materials, failure mechanisms, and failure circumstances.

Rolling-element bearings use rolling elements interposed between two raceways, and relative motion is permitted by the rotation of these elements. This article presents an overview of bearing materials, bearing-load ratings, and an examination of failed bearings. Rolling-element bearings are designed on the principle of rolling contact rather than sliding contact; frictional effects, although low, are not negligible, and lubrication is essential. The article lists the typical characteristics and causes of several types of failures. It describes failure by wear, failure by fretting, failure by corrosion, failure by plastic flow, failure by rolling-contact fatigue, and failure by damage. The article discusses the effects of fabrication practices, heat treatment and hardness of bearing components, and lubrication of rolling-element bearings with a few examples.

A wide range of mechanical properties can be obtained with a given composition of cast iron, depending on the microstructural constituents that form during solidification and subsequent solid-state processing. This article discusses the mechanical properties of gray iron and provides some general property comparisons with malleable, ductile (nodular), and compacted graphite irons. The mechanical properties of gray iron are determined by the combined effects of its chemical composition, processing technique in the foundry, and cooling rates during solidification. The article provides information on the classification of gray irons based on ASTM International specification A48/A48M. It discusses the loading effect, surface effect, notch sensitivity, and environmental effect on the mechanical properties of gray iron. The chemical composition ranges of some of the more widely used heat-resistant gray irons suitable for elevated-temperature service are presented in a table.