This SAE Recommended Practice is intended to provide a uniform means of identification which may be used to classify the friction coefficient of brake linings, based on data obtained from tests conducted in accordance with SAE J661 Brake Lining Quality Test Procedure and SAE J2975 Measurement of Copper and other elements in Brake Friction Materials.

NOTE: It is emphasized that this document does not establish friction requirements for brake linings, nor does it designate significant characteristics of brake linings which must be considered in overall brake performance. Due to other factors that include brake system design and operating environment, the friction codes obtained from this document cannot reliably be used to predict brake system performance.

The data given in Tables 1–4 are typical values only and are not intended for design parameters. Mechanical properties of the special purpose alloys depend greatly upon processing variables and heat treatment. It is recommended that design data be obtained by actual testing or by consultation with the producers of the alloys.

SIMILAR SPECIFICATIONS—UNS Z33521, former SAE 903, ingot is similar to ASTM B 240-79, Alloy AG40A; and UNS Z33520, former SAE 903, die casting is similar to ASTM B 86-76, Alloy AG40A. UNS Z35530, former SAE 925, ingot is similar to ASTM B 240-79, Alloy AC41A; and UNS Z35531, former SAE 925, die casting is similar to ASTM B 86-82a, Alloy AC41A.

This standard covers the identification, classification, and chemical composition of tool and die steels for use by engineers, metallurgists, tool designers, tool room supervisors, heat treaters, and tool makers.

This report lists approximate hardness conversion values; test methods for Vickers Hardness, Brinell Hardness, Rockwell Hardness Rockwell Superficial Hardness, Shore Hardness; and information regarding surface preparation, specimen thickness, effect of curved surfaces, and recommendations for Rockwell surface hardness testing for case hardened parts.

The tables in this report give the approximate relationship of Vickers Brinell, Rockwell, and Scleroscope hardness values and corresponding approximate tensile strengths of steels. It is impossible to give exact relationships because of the inevitable influence of size, mass, composition, and method of heat treatment. Where more precise conversions are required, they should be developed specially for each steel composition, heat treatment, and part.

The accompanying conversion tables for steel hardness numbers are based on extensive tests on carbon and alloy steels, mostly in the heat treated condition, but have been found to be reliable on practically all constructional alloy steels and tool steels in the as-forged, annealed, normalized, and quenched and tempered conditions, provided they are homogeneous. Such special cases as high manganese steel, 18% chromium— 8% nickel steel and other austenitic steels, and nickel base alloys, as well as constructional alloy steels and tool steels in the cold worked condition, may not conform to the relationships given with the same degree of accuracy as the steels for which the tables are intended.

All numbers in these tables given in bold face type were prepared jointly by the American Society for Testing and Materials, the American Society for Metals, and SAE from carefully checked data. The values given in regular face type were taken from the Army-Navy Approximate Hardness Tensile Strength Relationship of Carbon and Low Alloy Steels (ANQQ-H-201) published in the 1943 SAE Handbook, with only minor adjustments.

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.

Supplementary to the heat or cast analysis, a product analysis may be made on steel in the semifinished or finished form. For definitions and methods of sampling steel for product chemical analysis, refer to SAE J408.

A product analysis is a chemical analysis of the semifinished or finished steel to determine conformance to the specification requirements. The range of the specified chemical composition is normally expanded to take into account deviations associated with analytical reproducibility and the heterogeneity of the steel. Individual determinations may vary from the specified heat or cast analysis ranges or limits to the extent shown in Tables 1 through 5. The several determinations of any element in a heat or cast may not vary both above and below the specified range except for lead. Tables 1 through 5 provide permissible limits for various steel forms and composition types.

For rephosphorized and resulfurized steels, the product analysis tolerance limits are not applicable to phosphorus and sulfur because of the degree to which these elements segregate.

Boron is not subject to product analysis tolerances.

This SAE Standard describes a new alphanumeric designation system for wrought steel used to designate wrought ferrous materials, identify chemical composition, and any other requirements listed in SAE Standards and Recommended Practices.

The previous SAE steel designation coding system consisted of four or five numbers used to designate standard carbon and alloy steels specified to chemical composition ranges. Using SAE 1035 as an example, the 35 represents the nominal weight % carbon content for the grade. Using SAE 52100 as an example, the 100 represents the nominal weight % carbon content. The first two numbers of this four or five number series are used to designate the steel grade carbon or alloy system with variations in elements other than carbon. These are described in Table 1. In addition to the standard four or five number steel designation above, a letter was sometimes added to the grade code to denote a non-standard specific element being added to the standard grade. For example, with SAE 10B21, B designates a boron addition; with SAE 12L14, L designates a lead addition; and with SAE 10V45, V designates a vanadium addition.

For many years, the SAE four or five character steel designation system has provided a simple way to identify and label steel grades. However, it is not comprehensive enough to allow for the accurate coding of popular new or non-standard chemistry grades, different chemistries for the same grade that traditionally have been associated with a specific product form, eg. SAE 1006 and SAE 1008, steel grades with dual chemistry and mechanical property requirements, microalloyed grades, and grades with both chemistry and hardenability requirements. As a result, these grades could not be properly recorded within the constraints of the previous steel designation system and were not included in the SAE steel grade Tables in SAE J403/J404 and other SAE documents. The new steel designation system is meant to ensure that the original or old SAE steel grades are still usable and both old and new SAE grades can be referenced uniformly between Standards organizations. Since the UNS numbering system for metals provides the basis for the recording of steel grades between North American and International Standards organizations, UNS was used as the framework of the new coding system. However, in order for the traditional five number UNS code to be used, it had to be expanded and modified to allow for an increase in the number of grades that would need to be classified in the future and to provide proper coding of new or non-standard element modifications, corresponding element ranges and dual hardenability, mechanical property or special processing requirements.

These new steel designations are the same in both the UNS and SAE systems, as described in this standard (J402) and the joint SAE J1086/ASTM E527 UNS Publication. An alphanumeric code has been developed to identify the composition of SAE steel grades.

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 ladle analysis ranges plus certain product (check) 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 (reference SAE J408).

ISTC Division 1 has developed a procedure which allows for the maintenance of the grade list in this SAE Standard. This will involve conducting an industry-wide survey to solicit input. This survey will be conducted at a frequency deemed necessary by the technical committee. Criteria have been established for the addition to or deletion of grades from the grade table. A new grade will be considered if it meets standard SAE grade ranges, has a minimum usage or production of 225 tonnes/year (250 tons/year), and has the endorsement of at least two users or producers. New steel compositions will still be considered as Potential Standard (PS) steels, based on the guidelines provided in SAE J1081, until such time as production of the new steel achieves a level of production or usage qualifying it for consideration as a standard steel.

The deletion of a grade from the grade table will be by consensus based on the grade survey results. Deleted grades will be archived in SAE J1249 for future reference.

The compositions in this document may apply to open hearth and basic oxygen, or electric furnace steels. Grades shown in Table 1 with prefix letter E are normally made by the electric furnace process with maximum limits of 0.025% phosphorus and 0.025% sulfur. The nominal chemical limits or ranges in the compositions given in Table 1 are subject to standard variations in check analysis given in SAE J409. Since AISI is no longer issuing steel grade designations, all grades listed in this document are SAE grades.