ANSI/AGMA C08 includes updated and extensively revised information from ANSI/AGMA B89 along with additional information needed to achieve . Download ANSI-AGMA B Gear Materials and Heat Treatment Manual. Index of AGMA Standards and Information Sheets by Number. 1 ANSI/AGMA B89 Gear Materials and Heat. Treatment Manual.
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Refer to Table for chemical analyses of common cast copper bronze alloys, including phosphor or tin bronze, leaded tin bronze afma machinability and higher strength manganese bronze and aluminum bronze. Flame hardened parts which are air quenched are self tempered, and separate tempering is unnecessary. Each design above can be made by forging or agm fabrication.
The hardness and mechanical properties achieved from the quench and temper process are higher than those achieved from the normalize or anneal process.
See Tables, and for grades and recommended heat treatments. It should be of the same specified 200-4b89 grade, with regard to composition and hardenability limits, as the gear it represents. Improved cleanliness reduced nonmetallic inclusion content results in improved transverse ductility and impact strength, but machinability may be reduced; for example, with sulfur content less than 0.
Generally, steels with carbon content of approximately abma. Through hardening does not imply equal hardness through all sections of the part. These heat treatments produce ferritic, pearlitic or martensitic structures. Specified minimum hardness must be maintained to the finish machined dimensions for acceptance.
Carburized gear ratings are higher than the ratings for through hardened and other types of surface hardened gearing because of higher fatigue strength.
Although several powder metal materials are available, alloy steel is usually specified for gear applications. There are two basic methods of flame or induction hardening gears, spin hardening and tooth to tooth hardening. Deep case depths require prohibitive time cycles. Quenched and tempered ductile iron has good machinability up to HB and fair machinability up to HB.
Also, as a result of lower mass, fragmented shot particles will lengthen the time to reach a specified peening intensity.
Aluminum bronze materials are similar to the manganese bronzes in toughness, but are lighter in weight and attain higher mechanical properties through heat treatment. Selection of the tempering temperature must be based upon the specified hardness range, material composition, and the as quenched hardness.
These gases are each mixed with air in particular ratios and are burned under pressure to generate the flame which the burner directs on the work piece. The following supplementary requirement should apply only when specified by contractual agreement.
Tolerancing must consider these changes. Historically, this has been interpreted to mean that the specified hardness must be met at this location. This process, like other tooth to tooth hardening techniques, is time consuming and is not economical for small, finer pitch gearing finer than 10 DP.
Carburizing technology is well established and the available equipment and controls make it a reliable process. An upset forging is produced when the billet is initially hot worked in one direction, and then is rotated 90 degrees and hot worked again. The nitride process is restricted by and specified by case depth, surface hardness, core hardness and material selection constraints. A one inch 25 mm diameter bar, four inches mm in length is first normalized then uniformily heated to a standard austenitizing temperature.
Because the process increases bending fatigue strength, it may be used either to salvage or upgrade a gear design. High concentration polymer should be used with caution.
[PDF] ANSI-AGMA B Gear Materials and Heat Treatment Manual – Free Download PDF
Tempering is mandatory only when specified. Heavy draft, cold drawn, stress relieved bars may be used as an alternative to quench and tempered steel. Lower core hardness results in a microstructure which causes a lower ama hardness nitrided case, since it limits the ability to form high concentration of hard metallic nitrides. Round bars can be purchased in various diameters for standard carbon and alloy grades.
Flat stock is typically available in hot rolled or hot rolled and annealed conditions. The nitriding process will cause a slight uniform ama in size. Specifications are specialized and should be resolved between the user and supplier.
ANSI-AGMA 2004-B89-1995 Gear Materials and Heat Treatment Manual
However, sulfur, lead and calcium inclusions which improve machinability can decrease mechanical properties, particularly in the transverse direction. Martensite is the diffussionless transformation of austenite to a body centered tetragonal structure, characterized by an acicular needlelike appearance.
The purpose of this Section is to establish methods for specifying carbonitrided gearing. Microhardness tests for surface hardness should be made on a mounted and polished crosssection at a depth of 0. However, care should 2004-89 taken to avoid needlessly increasing material costs by changing to a higher hardenability steel where service life has been successful.
One inch 25 mm diameter? Through hardened gears 2004-h89 heated to a required temperature and cooled in the furnace or quenched in air, gas or liquid. It may be advisable to specify by use of photomicrographic standards both acceptable and nonacceptable phase distributions in the gear rim section.
Test specimens must be clean and machined dry. The temperature of the quenchant may affect ayma ability to extract heat. Heat Treat Process Control. In some instances, it may be desirable to specify multiples abma percent in an attempt to achieve more blending of a poorly machined surface.
Hardness and strengths able to be obtained by normalize and tempering are also a function of controlling section size and tempering temperature considerations.