This appendix provides a description of the hardness code and specification of hardness numbers for metals.

This appendix lists approximate equivalent hardness numbers and tensile strengths for Vickers hardness numbers for steel.

This appendix lists approximate equivalent hardness numbers and tensile strengths for Brinell hardness numbers for steel.

This appendix lists approximate equivalent hardness numbers and tensile strengths for Rockwell C and B hardness numbers for steel.

Hardness tests provide valuable information about the quality of materials and how they are likely to perform in different types of service. This chapter covers some of the most widely used hardness testing methods, including Vickers, Rockwell, and Brinell tests, Shore scleroscope and Equotip hardness tests, and microindentation tests. It describes the equipment and procedures used, discusses the factors that influence accuracy, and provides hardness conversion equations for different types of materials. It also explains how hardness testing sheds light on anisotropy, machinability, wear, fracture toughness, and tensile strength as well as temperature effects, residual stress, and quality control.

This chapter discusses the general principles of measuring hardness and hardenability of steel. The discussion begins by defining hardness and exploring the history of hardness testing. This is followed by a discussion on the principles, applications, advantages, and disadvantages of commonly used hardness testing systems: the Brinell, Rockwell, Vickers, Scleroscope, and various microhardness testers that employ Vickers or Knoop indenters. The effect of carbon content on annealed steels and hardened steels is then discussed. A brief discussion on the concept of the ideal critical diameter and austenitic grain size of steels is also provided to understand how one can calculate and quantify hardenability. The processes involved in various methods for evaluating hardenability are reviewed, discussing the effect of alloying elements on hardenability.

This appendix is a collection of tables listing examples of published hardness conversion equations, approximate Rockwell B and C hardness conversion numbers for nonaustenitic steels, and equivalent hardness numbers for Brinell hardness numbers and Vickers (diamond pyramid) hardness numbers for steel.

The properties of martensite and the mechanisms that govern its formation are the key to understanding hardness and the hardenability of carbon steel. Martensite is a transformation product of austenite that requires rapid cooling to suppress diffusion-dependent transformation pathways. This chapter describes the conditions that must be met for martensite to form. It discusses the role of quenching and the factors that affect cooling rate, including heat transfer, thermal diffusivity, emissivity, and section size. It defines hardenability and explains how to quantify it using the Grossmann-Bain approach or Jominy end-quench testing. It also explains how hardenability can be improved through the addition of boron, phosphorus, and other alloys.

This appendix is a compilation of approximate equivalent hardness numbers and tensile strengths for carbon and alloy steels in the annealed, normalized, and quenched-and-tempered conditions.

This appendix includes tables and figures that provide approximate Brinell equivalent hardness numbers for steels.

This chapter discusses the operating mechanism, applications, advantages, and limitations of Brinell hardness testing, Rockwell hardness testing, Vickers hardness testing, Scleroscope hardness testing, and microhardness testing. In addition, the general precautions and selection criteria to be considered are described and details of equipment setup provided.

The hardenability of steel 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 introduces the methods to evaluate hardenability and the factors that influence steel hardenability and selection. The discussion covers processes involved in Jominy end-quench test for evaluating hardenability. The effect of carbon on hardenability data and the effect of alloys on hardenability during quenching and on the tempering response (after hardening) are also discussed. In addition, the article provides information on the hardenability limits of H-steels after a note on hardenability correlation curves and Jominy equivalence charts.

This chapter describes the procedures, characteristics, and applications for static hardness test methods. It addresses test methods that are state of the art, commonly used, or that may find increased use due to certain advantages. The methods addressed are Rockwell hardness testing (ISO 6508 and ASTM E 18), Vickers hardness testing (ISO 6507, ASTM E92, and ASTM E384), Brinell hardness testing (ISO 6506 and ASTM E10), and Knoop hardness testing (ISO 4545 and ASTM E284). The chapter also discusses the advantages and disadvantages of these test methods.

This chapter discusses the characteristics, advantages, and disadvantages of nondestructive hardness testing methods for metals, including electromagnetic impulse testing, photothermal testing, scratch hardness testing, and ultrasonic contact impedance testing. It also discusses the use of ultrasound to determine the depth of hardening in a metal or alloy. The chapter reviews methods used to check and calibrate hardness testing machines and indenters and the use of hardness reference blocks for verification and calibration of test machines. It also addresses conversion of hardness values determined by one method to equivalent values for a different method.

This chapter reviews the tests and procedures used for measuring hardness of plastics and elastomers. The conventional testing methods (Rockwell, Vickers, Brinell, and Knoop) used for testing of metals are based on the idea that hardness represents the resistance against permanent plastic deformation of the material to be tested. However, elastic deformation must be considered in hardness measurement of elastomers. This chapter discusses the equipment and processes involved in the durometer (Shore) test, the International Rubber Hardness Degree test, and other specialized tests. It presents the criteria that can be used to select a suitable hardness testing method for elastomers or plastics and describes processes involved in specimen preparation and equipment calibration.

This chapter discusses the history of hardness testing and defines the term hardness. It describes the interrelationship between material structure and hardness and the relationships between hardness and other mechanical material properties. In addition, information on the hardness unit and traceability of the hardness measurement are provided.

This appendix presents a comparison of hardness tests on indenters for different loads along with the applications of these tests.

This chapter discusses the extrusion characteristics of hard aluminum alloys, particularly those in the 5000 and 7000 series. It begins with a review of two studies, one showing how the extrudability of 7 xxx alloys varies with the presence and amount of different alloying elements, the other relating minimum wall thickness with circumscribing circle diameter. It then explains how oxides on either the billet or container complicate the control of extrusion as well as auxiliary processes and how material flow and the movement of trapped gasses in different regions of the extrusion can lead to defects and variations in strength. It also discusses the extrusion of aluminum matrix composites and explains how composite billets are made.