ASTM E18-2019 pdf free download

ASTM E18-2019 pdf free download.Standard Test Methods for Rockwell Hardness of Metallic Materials
1. Scope
1.1 These test methods cover the determination of the Rockwell hardness and the Rockwell superficial hardness of metallic materials by the Rockwell indentation hardness prin- ciple. This standard provides the requirements for Rockwell hardness machines and the procedures for performing Rock- well hardness tests. 1.2 This test method includes requirements for the use of portable Rockwell hardness testing machines that measure Rockwell hardness by the Rockwell hardness test principle and can meet all the requirements of this test method, including the direct and indirect verifications ofthe testing machine. Portable Rockwell hardness testing machines that cannot meet the direct verification requirements and can only be verified by indirect verification requirements are covered in Test Method E110.1.5 Units—At the time the Rockwell hardness test was developed, the force levels were specified in units of kilograms-force (kgf) and the indenter ball diameters were specified in units of inches (in.). This standard specifies the units of force and length in the International System of Units (SI); that is, force in Newtons (N) and length in millimeters (mm). However, because of the historical precedent and continued common usage, force values in kgf units and ball diameters in inch units are provided for information and much of the discussion in this standard refers to these units. 1.6 The test principles, testing procedures, and verification procedures are essentially identical for both the Rockwell and Rockwell superficial hardness tests. The significant differences between the two tests are that the test forces are smaller for the Rockwell superficial test than for the Rockwell test. The same type and size indenters may be used for either test, depending on the scale being employed. Accordingly, throughout this standard, the term Rockwell will imply both Rockwell and Rockwell superficial unless stated otherwise. 1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.8 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. Terminology and Equations
3.1 Definitions: 3.1.1 calibration—determination of the values of the sig- nificant parameters by comparison with values indicated by a reference instrument or by a set of reference standards. 3.1.2 standardization—to bring in conformance to a known standard through verification or calibration. 3.1.3 verification—checking or testing to assure confor- mance with the specification. 3.1.4 Rockwell hardness test—an indentation hardness test using a verified machine to force a diamond spheroconical indenter or tungsten carbide (or steel) ball indenter, under specified conditions, into the surface of the material under test, and to measure the difference in depth of the indentation as the force on the indenter is increased from a specified preliminary test force to a specified total test force and then returned to the preliminary test force. 3.1.5 Rockwell superficial hardness test—same as the Rock- well hardness test except that smaller preliminary and total test forces are used with a shorter depth scale. 3.1.6 Rockwell hardness number—a number derived from the net increase in the depth of indentation as the force on an indenter is increased from a specified preliminary test force to a specified total test force and then returned to the preliminary test force. 3.1.7 Rockwell hardness machine—a machine capable of performing a Rockwell hardness test and/or a Rockwell super- ficial hardness test and displaying the resulting Rockwell hardness number. 3.1.7.1 Rockwell hardness testing machine—a Rockwell hardness machine used for general testing purposes. 3.1.7.2 Rockwell hardness standardizing machine—a Rock- well hardness machine used for the standardization of Rock- well hardness indenters, and for the standardization of Rock- well hardness test blocks. The standardizing machine differs from a regular Rockwell hardness testing machine by having tighter tolerances on certain parameters.