This document identifies metallurgical quality characteristics which are important to the performance of steel and cast iron gearing. The AGMA gear rating standards identify performance levels of gearing by heat treatment method and grade number. For each heat treatment method and AGMA grade number, acceptance criteria are given for various metallurgical characteristics identified in this document.
In November 1984, an ad hoc Metallurgy and Gear Rating Committee met to define the factors required to qualify the various metallurgical quality grades that were to be introduced into the gear rating standard that eventually became ANSI/AGMA 2001-B88, Fundamental Rating Factors and Calculation Methods for Involute Spur and Helical Gear Teeth.
In May 1988, ANSI/AGMA 6033-A88, Standard for Marine Propulsion Gear Units – Part 1, Materials, was published using a short list of metallurgical factors in table form.
In September 1988, ANSI/AGMA 2001-B88 was published using metallurgical factors in table form.
Starting in July 1992, AGMA representatives participated in writing ISO 6336-5, Calculation of Load Capacity of Spur and Helical Gears – Part 5: Strength and Quality of Materials, which was a modification of the tables in ANSI/AGMA and DIN Standards.
In February 1993, AGMA 6002-B93, Design Guide for Vehicle Spur and Helical Gears, was published using a modified version of the tables used in ANSI/AGMA 2001-B88.
In September 1993, the AGMA Metallurgy and Materials Committee accepted the task of consolidating the various tables to avoid redundancies and conflicting requirements, and started work on AGMA 923-A00, Metallurgical Specifications for Steel Gearing.
In January 1995, a revised ANSI/AGMA 2001-C95 was published using a version of the ANSI/AGMA 2001-B88 tables as revised by the AGMA Helical Gear Rating Committee.
In November 1997, a revised ANSI/AGMA 2003-B97, Rating the Pitting Resistance and Bending Strength of Generated Straight Bevel, Zerol Bevel and Spiral Bevel Gear Teeth, was published using a version of the ANSI/AGMA 2001-B88 tables as revised by the AGMA Bevel Gearing Committee.
The committee reviewed all metallurgical tables of the gear rating standards ANSI/AGMA 2001-B88, ANSI/AGMA 2003-A86, and ISO 6336-5:1996 and their proposed revisions to develop consolidated tables describing the metallurgical characteristics associated with each specific type of heat treatment and metallurgical quality grade. Effort was made to reference ISO specifications where possible. The consolidated tables were submitted to the gear rating committees for their agreement and are published here for reference by other standards.
AGMA’s goal is to develop a consistent metallurgical specification which reflects the quality requirements for steel gearing. AGMA 923-A00 was such a document and was intended to be consistent with the applicable portions of ISO 6336-5:1996, to the extent possible while the two standards were in parallel development. The AGMA Technical Division Executive Committee approved the publication of AGMA 923-A00 in August 2000.
AGMA 923-B05 incorporated changes to Item 8, microstructure, of Table 1, metallurgical characteristics for through hardened gearing. The balance of the document remains unchanged. The AGMA Technical Division Executive Committee approved the publication of AGMA 923-B05 in May 2005.
AGMA 923-C22 replaces AGMA 923-B05. This edition of the information sheet was developed to be consistent with ISO 6336-5:2016. An expanded reduction ratio calculation methodology with new figures has been added to the procedures section. In addition, metallurgical tables have been updated as follows:
- listing of requirements sequentially;
- chemistry and cleanliness requirements were added;
- footnotes were reworded and renumbered for uniformity;
- new metallurgical tables were added for gray cast iron, ductile iron, and austempered ductile iron.
The first draft of AGMA 923-C22 was created in November 2013. It was approved by the Technical Division Executive Committee (TDEC) in August 2022.
Metallurgical quality characteristics for use in conjunction with AGMA gear rating standards are recommended. Three different metallurgical quality grades: grade 1, grade 2, and grade 3 are defined. Characteristics include raw material, heat treatment, post heat treat processing, and associated inspections. Gear design and rating, case depth, allowable stress numbers, and quality control sampling plans are not included.
The following standards contain provisions which, through reference in this text, constitute provisions of this document. At the time of initial development, the editions shown were valid. All standards are subject to revision, and parties to agreements based on this document are encouraged to investigate the possibility of applying the most recent editions of the standards shown below.
AGMA 904, Metric Usage
ANSI/AGMA 1010, Appearance of Gear Teeth – Terminology of Wear and Failure
ANSI/AGMA 1012, Gear Nomenclature, Definitions of Terms with Symbols
ANSI/AGMA 2001, Fundamental Rating Factors and Calculation Methods for Involute Spur and Helical Gear Teeth
ANSI/AGMA 2003, Rating the Pitting Resistance and Bending Strength of Generated Straight Bevel, Zerol Bevel and Spiral Bevel Gear Teeth
ANSI/AGMA 2004, Gear Materials and Heat Treatment Manual
ANSI/AGMA ISO 14104, Gears – Surface Temper Etch Inspection After Grinding – Chemical Method
ANSI/AGMA 6002, Design Guide for Vehicle Spur and Helical Gears
ASTM A29/A29M, Specification for Steel Bars, Carbon and Alloy, Hot-Wrought, General Requirements
ASTM A148/A148M, Specification for Steel Castings, High Strength, for Structural Purposes
ASTM A247, Standard Test Method for Evaluating the Microstructure of Graphite in Iron Castings
ASTM A255, Standard Test Methods for Determining Hardenability of Steel
ASTM A275/A275M, Test Method for Magnetic Particle Examination of Steel Forgings
ASTM A370, Standard Test Methods and Definitions for Mechanical Testing of Steel Products
ASTM A388/A388M, Standard Practice for Ultrasonic Examination of Steel Forgings
ASTM A519/A519M, Standard Specification for Seamless Carbon and Alloy Steel Mechanical Tubing
ASTM A534, Standard Specification for Carburizing Steels for Anti-Friction Bearings
ASTM A536, Standard Specification for Ductile Iron Castings
ASTM A609/A609M, Standard Practice for Castings, Carbon, Low-Alloy, and Martensitic Stainless Steel, Ultrasonic Examination Thereof
ASTM A751, Test Methods, Practices, and Terminology for Chemical Analysis of Steel Products
ASTM A866-18, Standard Specification for Medium Carbon Anti-Friction Bearing Steel
ASTM A897, Standard Specification for Austempered Ductile Iron Castings
ASTM A941, Standard Terminology Relating to Steel, Stainless Steel, Related Alloys, and Ferroalloys
ASTM A956, Standard Test Method for Leeb Hardness Testing of Steel Products
ASTM A1038, Standard Test Method for Portable Hardness Testing by the Ultrasonic Contact Impedance Method
ASTM E3, Practice for Preparation of Metallographic Specimens
ASTM E8/E8M, Standard Test Methods for Tension Testing of Metallic Materials
ASTM E10, Standard Test Method for Brinell Hardness of Metallic Materials
ASTM E18, Standard Test Methods for Rockwell Hardness of Metallic Materials 1, 2
ASTM E23, Standard Test Methods for Notched Bar Impact Testing of Metallic Materials
ASTM E45, Standard Test Methods for Determining the Inclusion Content of Steel
ASTM E92, Standard Test Methods for Vickers Hardness and Knoop Hardness of Metallic Materials
ASTM E110, Standard Test Method for Indentation Hardness of Metallic Materials by Portable Hardness Testers
ASTM E112, Standard Test Methods for Determining Average Grain Size
ASTM E125, Standard Reference Photographs for Magnetic Particle Indications on Ferrous Castings
ASTM E140, Standard Hardness Conversion Tables for Metals Relationship Among Brinell Hardness, Vickers Hardness, Rockwell Hardness, Rockwell Superficial Hardness, Knoop Hardness, Scleroscope Hardness, and Leeb Hardness
ASTM E350, Standard Test Methods for Chemical Analysis of Carbon Steel, Low-Alloy Steel, Silicon Electrical Steel, Ingot Iron, and Wrought Iron
ASTM E351, Standard Test Methods for Chemical Analysis of Cast Iron – All Types
ASTM E407, Standard Practice for Microetching Metals and Alloys
ASTM E1077, Standard Test Methods for Estimating the Depth of Decarburization of Steel Specimens
ASTM E1444, Practice for Magnetic Particle Examination
ISO 185, Grey Cast Irons – Classification
ISO 642, Steel – Hardenability test by end quenching (Jominy test)
ISO 643, Steels – Micrographic determination of the ferritic or austenitic grain size
ISO 683-1, Heat-treatable steels, alloy steels and free-cutting steels – Part 1: Direct-hardening unalloyed and low-alloyed wrought steel in form of different black products
ISO 683-11, Heat-treatable steels, alloy steels and free-cutting steels – Part 11: Wrought case-hardening steels
ISO 945, Microstructure Of Cast Irons
ISO 1083, Spheroidal Graphite Cast Irons – Classification
ISO 4967, Steel – Determination of content of non-metallic inclusions – micrographic method using standard diagrams
ISO 6336-5, Calculation of load capacity of spur and helical gears – Part 5: Strength and quality of materials
ISO 17804, Founding – Ausferritic spheroidal graphite cast irons – Classification
ISO 18265, Metallic Materials – Conversion of Hardness Values
SAE/AMS 2300, Premium Aircraft-Quality Steel Cleanliness, Magnetic Particle Inspection Procedure
SAE/AMS 2301, Cleanliness, Aircraft Quality Steel Magnetic Particle Inspection Procedure
SAE/AMS 2304, Special Aircraft-Quality Steel Cleanliness, Magnetic Particle Inspection Procedure
SAE/AMS-S-13165, Shot Peening of Metal Parts
SAE J419, Methods of Measuring Decarburization
SAE J423, Methods of Measuring Case Depth
SAE J864, Surface Hardness Testing with Files