ASTM A255-2018 pdf free download

ASTM A255-2018 pdf free download.Standard Test Methods for Determining Hardenability of Steel
1. Scope
1.1 These test methods cover the identification and descrip- tion oftest methods for determining the hardenability ofsteels. The two test methods include the quantitative end-quench or Jominy Test and a method for calculating the hardenability of steel from the chemical composition based on the original work by M. A. Grossman. 1.2 The selection of the test method to be used for deter- mining the hardenability of a given steel shall be agreed upon between the supplier and user. The Certified Material Test Report shall state the method of hardenability determination. 1.3 The calculation method described in these test methods is applicable only to the range of chemical compositions that follow:1.4 Hardenability is a measure of the depth to which steel will harden when quenched from its austenitizing temperature (Table 1). It is measured quantitatively, usually by noting the extent or depth ofhardening ofa standard size and shape oftest specimen in a standardized quench. In the end-quench test the depth of hardening is the distance along the specimen from the quenched end which correlates to a given hardness level. 1.5 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.6 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. 1.7 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.
5. Test Specimens
5.1 Wrought Specimens—End-quench specimens shall be prepared from rolled or forged stock and shall represent the full cross section of the product. If negotiated between the supplier and the user, the end-quench specimen may be prepared from a given location in a forged or rolled product or from a continuous cast billet. The test specimen shall be 1.0 in. (25.4 mm) in diameter by 4.0 in. (101.6 mm) in length, with means for hanging it in a vertical position for end quenching. Dimensions of the preferred specimen and of an optional specimen (Note 2) are given in Figs. 2 and 3. The specimen shall be machined from a bar previously normalized in accordance with 6.1 and of such size as to permit the removal ofall decarburization in machining to 1.0 in. round. The end of the specimen to be water cooled shall have a reasonably smooth finish, preferably produced by grinding. Normalizing may be waived by agreement between the supplier and the user. The previous thermal history of the specimen tested shall always be recorded. 5.2 Cast Specimens—A separately cast end-quench speci- men may be used for non-boron steels. Cast specimens are not suitable for boron steel grades due to erratic results. A graphite or metal mold may be used to form an overlength specimen 1.0 in. (25.4 mm) in diameter which shall be cut to the standard specimen size. The mold may also be used to form a 1.25-in. (31.8-mm) diameter specimen which shall be machined to the final specimen size. Cast tests need not be normalized.Heating—Place the specimen in a furnace that is at the specified austenitizing temperature (Table 1) and hold at this temperature for 30 min. In production testing slightly longer times up to 35 min may be used without appreciably affecting results. It is important to heat the specimen in such an atmosphere that practically no scaling and a minimum of decarburization takes place. This may be accomplished by heating the specimen in a vertical position in a container with an easily removable cover containing a layer of cast-iron chips with the bottom face of the specimen resting on the chips.