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In 1941, the SAE Iron and Steel Division, in collaboration with the American Iron and Steel Institute (AISI), made a major change in the method of expressing composition ranges for the SAE steels. The plan, as now applied, is based in general on narrower cast or heat analysis ranges plus certain product analysis allowances on individual samples, in place of the fixed ranges and limits without tolerances formerly provided for carbon and other elements in SAE steels. For years the variety of chemical compositions of steel has been a matter of concern in the steel industry. It was recognized that production of fewer grades of steel could result in improved deliveries and provide a better opportunity to achieve advances in technology, manufacturing practices, and quality, and thus develop more fully the possibilities of application inherent in those grades.

The purpose of this SAE Recommended Practice is to describe the terms yield strength and yield point. Included are definitions for both terms and recommendations for their use and application.

The figures in this SAE Information Report illustrate the principle that, regardless of composition, steels of the same cross-sectional hardness produced by tempering after through hardening will have approximately the same longitudinal1 tensile strength at room temperature. Figure 1 shows the relation between hardness and longitudinal tensile strength of 0.30 to 0.50% carbon steels in the fully hardened and tempered, as rolled, normalized, and annealed conditions. Figure 2 showing the relation between longitudinal tensile strength and yield strength, and Figure 3 illustrating longitudinal tensile strength versus reduction of area, are typical of steels in the quenched and tempered condition. Figure 3 shows the direct relationship between ductility and hardness and illustrates the fact that the reduction of area decreases as hardness increases, and that, for a given hardness, the reduction of area is generally higher for alloy steels than for plain carbon steels.

This SAE Information Report provides a list of those SAE steels which, because of decreased usage, have been deleted from the standard SAE Handbook listings. Included are alloy steels from SAE J778 deleted since 1936, carbon steels from SAE J118 deleted since 1952, and all EX-steels deleted from SAE J1081. Information concerning SAE steels prior to these dates may be obtained from the SAE office on request. With the issuance of this report, SAE J778, Formerly Standard SAE Alloy Steels, and SAE J118, Formerly Standard SAE Carbon Steels, will be retired since they are now combined in SAE J1249. In the future, new assignments to SAE J1081, Chemical Compositions of SAE Experimental Steels, will be given “PS” (Potential Standard) numbers rather than “EX” numbers. The steels listed in Tables 1 and 2 are no longer considered as standard steels. Producers should be contacted concerning availability.

The SAE system of designating steels, described in SAE J402, classifies and numbers them according to chemical composition. In the case of the high-strength, low-alloy steels in SAE J1392 and J1442 and the high-strength carbon and alloy die drawn steels in SAE J935, minimum mechanical property requirements have been included in the designations. In addition, hardenability data on most of the alloy steels and some of the carbon steels will be found in SAE J1268.

This SAE Standard prescribes the procedure for making hardenability tests and recording results on shallow and medium hardening steels, but not deep hardening steels that will normally air harden. Included are procedures using the 25 mm (1 in) standard hardenability end-quench specimen for both medium and shallow hardening steels and subsize method for bars less than 32 mm (1-1/4 in) in diameter. Methods for determining case hardenability of carburized steels are given in SAE J1975. Any hardenability test made under other conditions than those given in this document will not be deemed standard and will be subject to agreement between supplier and user. Whenever check tests are made, all laboratories concerned must arrange to use the same alternate procedure with reference to test specimen and method of grinding for hardness testing.

This SAE Information Report describes the processing and fabrication of carbon and alloy steels. The basic steelmaking process including iron ore reduction, the uses of fluxes, and the various melting furnaces are briefly described. The various types of steels: killed, rimmed, semikilled, and capped are described in terms of their melting and microstructural differences and their end product use. This document also provides a list of the commonly specified elements used to alloy elemental iron into steel. Each element’s structural benefits and effects are also included. A list of the AISI Steel Products Manuals is included and describes the various finished shapes in which steel is produced.

This SAE Information Report relates to hot-rolled steel bar products. It is intended as a guideline to assist in the selection and specification of hot-rolled steel bar; however, it is not to be interpreted as a material specification in itself.

All carbon and alloy H-band steels are shown, along with their corresponding minimum and maximum hardenability limits, for which sufficient hardenability data have been established and for grades which use the standard end-quench test. As hardenability data are accumulated for other grades, this SAE Standard will be revised to include such grades.

This SAE Standard prescribes the procedure for making hardenability tests and recording results on shallow and medium hardening steels, but not deep hardening steels that will normally air harden. Included are procedures using the 25 mm (1 in) standard hardenability end-quench specimen for both medium and shallow hardening steels and subsize method for bars less than 32 mm (1-1/4 in) in diameter. Methods for determining case hardenability of carburized steels are given in SAE J1975. Any hardenability test made under other conditions than those given in this document will not be deemed standard and will be subject to agreement between supplier and user. Whenever check tests are made, all laboratories concerned must arrange to use the same alternate procedure with reference to test specimen and method of grinding for hardness testing.

This SAE Recommended Practice covers six levels of high strength carbon and high-strength low-alloy steel plates, bars, and shapes for structural use. The six strength levels are 290, 345, 415, 450, 485, and 550 MPa or 42, 50, 60, 65, 70, and 80 ksi minimum yield point. Different chemical compositions are used to achieve the specified mechanical properties. In some cases there are significant differences in chemical composition for the same strength level, depending on the fabricating requirements. Because the chemical compositions may vary significantly among the producers, despite the required mechanical properties being the same, it is important that the fabricator consult with the producer to determine the relative effects of the producer's composition on the forming, welding, and field service requirements.

Restricted hardenability steels have been in use for some time but the specific restrictions for a particular grade depend upon customer needs and vary from mill to mill. Such steels are desirable to provide more controlled heat treatment response and dimensional control for critical parts. Because of increasing interest in steels with restricted hardenability, the SAE Iron and Steel Technical Committee directed Division 8 to prepare a set of standard steels with restricted hardenability. In 1993, the American Society for Testing and Materials (ASTM) adopted the twelve SAE restricted hardenability steels and added ten more. SAE decided to include in SAE J1868 the additional 10 steels. In general, steels with restricted hardenability (RH steels) will exhibit a hardness range not greater than 5 HRC at the initial position on the end-quench hardenability bar and not greater than 65% of the hardness range for standard H-band steels (see SAE J1268) in the "inflection" region.

H steels and their corresponding minimum and maximum hardenability limits are shown for all of the carbon and alloy steels for which there are sufficient hardenability data and for grades that can use the standard end quench test. As hardenability data are accumulated for other grades, this SAE Standard will be revised to include such grades.

This SAE Standard prescribes the procedure for making hardenability tests and recording results on shallow and medium hardening steels, but not deep hardening steels that will normally air harden. Included are procedures using the 25 mm (1 in) standard hardenability end-quench specimen for both medium and shallow hardening steels and subsize method for bars less than 32 mm (1-1/4 in) in diameter. Methods for determining case hardenability of carburized steels are given in SAE J1975. Any hardenability tests made under other conditions than those given in this document will not be deemed standard and will be subject to agreement between supplier and user. Whenever check tests are made, all laboratories concerned must arrange to use the same alternate procedure with reference to test specimen and method of grinding for hardness testing.

The purpose of this SAE Recommended Practice is to describe the terms yield strength and yield point. Included are definitions for both terms and recommendations for their use and application.

This SAE Information Report summarizes the characteristics of carburized steels and factors involved in controlling hardness, microstructure, and residual stress. Methods of determining case hardenability are reviewed, as well as methods to test for freedom from non-martensitic structures in the carburized case. Factors influencing case hardenability are also reviewed. Methods of predicting case hardenability are included, with examples of calculations for several standard carburizing steels. A bibliography is included in 2.2. The references provide more detailed information on the topics discussed in this document.

This SAE Standard prescribes the procedure for making hardenability tests and recording results on shallow and medium hardening steels, but not deep hardening steels that will normally air harden. Included are procedures using the 25 mm (1 in) standard hardenability end-quench specimen for both medium and shallow hardening steels, Surface-Area-Center (SAC) method for shallow hardening steels, subsize method for bars less than 32 mm (1¼ in) in diameter, and methods for determining carburized hardenability. (See Appendix A.) Any hardenability tests made under other conditions than those given in this document will not be deemed standard and will be subject to agreement between supplier and user. Whenever check tests are made, all laboratories concerned must arrange to use the same alternate procedure with reference to test specimen and method of grinding for hardness testing.

The figures in this SAE Information Report illustrate the principle that, regardless of composition, steels of the same cross sectional hardness produced by tempering after through hardening, will have approximately the same longitudinal1 tensile strength at room temperature. Figure 1 shows the relation between hardness and longitudinal tensile strength of 0.30 to 0.50% carbon steels in the fully hardened and tempered, as rolled, normalized, and annealed conditions. Figure 2 showing the relation between longitudinal tensile strength and yield strength, and Figure 3 illustrating longitudinal tensile strength versus reduction of area, are typical of steels in the quenched and tempered condition. Figure 3 shows the direct relationship between ductility and hardness and illustrates the fact that the reduction of area decreases as hardness increases, and that, for a given hardness, the reduction of area is generally higher for alloy steels than for plain carbon steels.

Restricted hardenability steels have been in use for some time but the specific restrictions for a particular grade depend upon customer needs and vary from mill to mill. Such steels are desirable to provide more controlled heat treatment response and dimensional control for critical parts. Because of increasing interest in steels with restricted hardenability, the SAE Iron and Steel Technical Committee directed Division 8 to prepare a set of standard steels with restricted hardenability. In general, steels with restricted hardenability (RH steels) will exhibit a hardness range not greater than 5 HRC at the initial position on the end-quench hardenability bar and not greater than 65% of the hardness range for standard H-band steels (see SAE J1268) in the "inflection" region. Generally the restricted hardenability band follows the middle of the corresponding standard H-band. An example of the RH band compared with the standard H-band is given for SAE 4140 in Figure 1.

This document describes the processing and fabrication of carbon and alloy steels. The basic steelmaking process including iron ore reduction, the uses of fluxes, and the various melting furnaces are briefly described. The various types of steels: killed, rimmed, semikilled, and capped are described in terms of their melting and microstructural differences and their end product use. This document also provides a list of the commonly specified elements used to alloy elemental iron into steel. Each element's structural benefits and effects are also included. A list of the AISI Steel Products Manuals is included and describes the various finished shapes in which steel is produced.