® AMS 2759DAEROSPACE Issued OCT 1984 Revised FEB 2006 MATERIAL Superseding AMS 2759C SPECIFICATION Heat Treatment of Steel Parts General Requirements RATIONALE AMS 2759D changes paragraph 3.3.1 by adding AMS 2759/11 to Table 1, 3.3.5, 3.3.5.1, 3.3.5.2, and 3.3.5.3 concerning purging, 4.2.2.3.2 concerning hardness test machines, 4.5 concerning logs, and 4.7 concerning reports. 1. SCOPE: 1.1 This specification establishes general requirements for the processes listed in 3.3.1 for heat treatment of steel parts (See 8.2.1) by users or their vendors or subcontractors. 1.2 Reference to AMS 2759 on a drawing, fabrication order, purchase order, etc constitutes a requirement to conform to the applicable provisions of the documents listed in 3.3.1 for the heat treatment of steel parts of the particular alloy described. Parts made from steels other than those specified in the detail specifications may be heat treated in accordance with the applicable requirements using processing temperatures, times, and other parameters recommended by the material producer unless otherwise specified by purchaser. 1.3 The conditions (temperatures, soaking times, cooling rates, etc) used by material producers, forge shops, and foundries for qualification of response to heat treatment of their products shall conform to the requirements of the specifications listed in 3.3.1. 1.4 Heat treatment of raw material by raw material producers, forge shops, or foundries should be in accordance with the material procurement specification. 1.5 Processes such as vacuum-furnace heat treating, flame hardening, induction through- hardening, austempering, martempering, and hot oil quenching are recognized heat treating processes, but their requirements are not completely covered by this specification. SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefrom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright © 2006 SAE International All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: 724-776-4970 (outside USA) Fax: 724-776-0790 Email:
[email protected] SAE WEB ADDRESS: http://www.sae.org Minimum Tensile Strength Below 220 ksi (1517 MPa) AMS 2759/2 Heat Treatment of Low-Alloy Steel Parts. It is the sole responsibility of the user to ensure familiarity with the safe and proper use of any hazardous materials and to take necessary precautionary measures to ensure the health and safety of all personnel involved.org. The supplier may work to a subsequent revision of a document unless a specific document issue is specified. Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA and Canada).1 SAE Publications: Available from SAE International.sae. 2. methods. 400 Commonwealth Drive. APPLICABLE DOCUMENTS: The issue of the following documents in effect on the date of the purchase order forms a part of this specification to the extent specified herein. Minimum Tensile Strength 220 ksi (1517 MPa) and Higher AMS 2759/3 Heat Treatment of Precipitation-Hardening Corrosion-Resistant and Maraging Steel Parts AMS 2759/4 Heat Treatment of Austenitic Corrosion-Resistant Steel Parts AMS 2759/5 Heat Treatment of Martensitic Corrosion-Resistant Steel Parts AMS 2759/6 Gas Nitriding and Heat Treatment of Low-Alloy Steel Parts AMS 2759/7 Gas and Vacuum Carburizing and Heat Treatment of Carburizing-Grade Steel Parts AMS 2759/8 Ion Nitriding AMS 2759/9 Hydrogen Embrittlement Relief (Baking) of Steel Parts AMS 2759/10 Automated Gaseous Nitriding Controlled by Nitriding Potential AMS 2759/11 Stress Relief of Steel Parts ARP1962 Training and Approval of Heat Treating Personnel -2- . the last published issue of that document shall apply. Warrendale.AMS 2759D SAE AMS 2759D 1. applications. AMS 2750 Pyrometry AMS 2759/1 Heat Treatment of Carbon and Low-Alloy Steel Parts.6 Safety . PA 15096-0001. this specification does not address the hazards which may be involved in such use. When the referenced document has been cancelled and no superseding document has been specified. www. and processes described or referenced in this specification may involve the use of hazardous materials.Hazardous Materials: While the materials. 2. test equipment. a concentration control system shall be established prior to production use.2. and Poisson’s Ratio for Advanced Ceramics by Impulse Excitation of Vibration ASTM E 8 Tension Testing of Metallic Materials ASTM E 8M Tension Testing of Metallic Materials (Metric) ASTM E 10 Brinell Hardness of Metallic Materials ASTM E 18 Rockwell Hardness and Rockwell Superficial Hardness of Metallic Materials ASTM E 384 Microhardness of Materials 2. ASTM A 370 Mechanical Testing of Steel Products ASTM C 848 Young's Modulus.4 Sampling Procedures and Tables for Inspection by Attributes 3. PA 19428-2959. Tel: 212-642-4900. prior to production use to ensure the adequacy of the agitation system and that the system is designed to minimize susceptibility to agitation variations. shall provide for agitation of the quench media or the parts. and system accuracy shall conform to AMS 2750. and shall have a temperature indicator with a sensor in the quench media. from contamination.AMS 2759D SAE AMS 2759D 2. 3. P. TECHNICAL REQUIREMENTS: 3.org.2).1. Quenching baths shall be free from visible contamination which could detrimentally affect the process. calibration equipment.ansi. Box C700.3 ANSI Publications: Available from American National Standards Institute.2 ASTM Publications: Available from ASTM International. 3. -3- . furnace temperature uniformity.org. load thermocouples (See 8. Shear Modulus. thermocouples.1. Instrumentation.1 Equipment and Pyrometry: Thermal processing equipment and related pyrometric equipment shall be controlled in accordance with AMS 2750. When using polymers. and Poisson's Ratio for Ceramic Whitewares by Resonance ASTM C 1259 Dynamic Young’s Modulus. New York. 100 Barr Harbor Drive. Shear Modulus.O.1 Heating and Refrigeration Equipment: Automatic temperature controllers and data recording instruments conforming to AMS 2750 are required on each furnace and mechanical refrigeration unit. West Conshohocken. Bath maintenance programs shall be established. ANSI/ASQC Z1. 25 West 43rd Street.astm. Temperature sensors shall be located in or adjacent to each work zone. www. Thermocouples shall be protected. NY 10036. shall be of sufficient volume to absorb the heat rejected by the most massive part to be quenched. Tel: 610-832-9598. and a system check shall be made. when necessary.2 Quenching Equipment: Quench baths shall permit complete immersion of parts. www. 3. a quenchant validation procedure shall be implemented when initially establishing the quenching procedure or when changing from one quenchant to another.5 Vacuum Equipment: Vacuum furnaces shall have a calibrated recording instrument for sensing the vacuum.1 When liquid quenching is required.AMS 2759D SAE AMS 2759D 3. a rinsing system shall be in place to remove quenchant from the parts. -4- . 3. to remove oil from parts quenched in oil baths.1. or polymer/water solutions may be used as specified for the alloy and temper indicated. jigs.2.2 Quenching Media: 3. oil and polymer quenchants shall be used within the temperature range recommended by the product manufacturer. water. hangers.4). The consistency of quench effectiveness shall be determined for each tank by testing initially and quarterly thereafter by one of the methods in 3.2.3).6 Servicing and Calibration of Atmosphere Control Equipment: Instrumentation used to control furnace atmosphere shall be calibrated and serviced according to manufacturer’s recommendation. trays.3 Auxiliary Equipment: Fixtures. 3. corrective action shall be taken and the tests repeated to verify restoration of the prior condition. When using polymer quenchants. racks. If results indicate that a quenchant is outside the established limits.1. In addition. and salt residue from parts heated or quenched in salt baths.2 Problems.2. due to an inappropriate quenchant or improperly designed system which is not appropriate for a particular alloy and configuration shall be avoided.4 Cleaning Equipment: Equipment shall be provided to clean parts before heat treatment. for proper handling of parts. 3. and shall not exceed 200 °F (93 °C) at any time during the quenching operation.1.1 When substituting a polymer/concentration for an existing oil quenchant.2. or quenching rates to less than required for correct hardening of parts. snorkels. such as cracking and high residual stresses. 3. the quenchant validation procedure shall ensure that the polymer and concentration being substituted achieves cooling characteristics which are similar to the existing oil quenchant and that the properties being produced are equivalent to those for oil quenched parts (See 8.1. as needed. Fixtures and fixture materials shall not cause contamination of parts and shall not reduce the heating. cooling. 3.3 Except when marquenching (See 8. 3.3).5.2. etc shall be employed. The heat treating facility shall establish control limits for each quenching system.2. oil.4 and comparing the results with those obtained previously by the same method.2. the temperature of the quenchant shall be in the range 60 to 160 °F (16 to 71 °C) at the initiation of the quenching operation. Because of wide differences in quenching characteristics of different quenchants in different quenching systems. unless otherwise approved by the cognizant engineering organization (See 8. 3.3.3.2.2.AMS 2759D SAE AMS 2759D 3. 3. and prior to heating of parts. This requirement does not apply if the heat treater has documented confirmation that material removal after heat treatment will ensure that all surfaces of finished parts will be free from contamination. where the quench chamber is below atmospheric pressure. or otherwise oriented.4 Quench oil used in integral quench vacuum furnaces. TABLE 1 . 3.3. 3. remnants of the previous atmosphere shall be removed from the furnace or retort and gas supply lines. neutral. shall be vacuum degassed at approximately the maximum recommended temperature for the oil initially and after each addition of oil. 3. as necessary.Heat Treatment Procedures Type of Steel or Process Procedure Carbon and Low-Alloy Below 220 ksi UTS AMS 2759/1 Low-Alloy 220 ksi UTS and Higher AMS 2759/2 PH and Maraging AMS 2759/3 Austenitic AMS 2759/4 Martensitic AMS 2759/5 Gas Nitriding AMS 2759/6 Gas and Vacuum Carburizing AMS 2759/7 Ion Nitriding AMS 2759/8 Hydrogen Embrittlement Relief (Baking) of AMS 2759/9 Steel Parts Automated Gaseous Nitriding Controlled by AMS 2759/10 Nitriding Potential Stress Relief of Steel Parts AMS 2759/11 3.2.5 Purging: Whenever the atmosphere type (e. primarily to ensure access of the heating. nitriding) is changed.6 Salt Removal: All salt residues shall be removed from parts processed in salt-baths or quenched in brine. and quenching media to all surfaces of all parts and secondarily to minimize warpage.1 The removal of the previous atmosphere shall be accomplished by purging with the replacement atmosphere at the highest temperature at which it will be used.5 Quenching from Salt Bath Furnaces: Water shall be monitored weekly to ensure salt content does not exceed 2% by weight.3.1 Heat Treatment: Shall be in accordance with Table 1. cooling. during or immediately following quenching.g.5.3 Procedure: 3. -5- . Polymers shall be monitored weekly to ensure salt content does not exceed 6% by weight. carburizing.3.3 Corrosion Protection: Parts shall be protected from corrosion during processing and storage.. 3. 3.4 Racking: Parts shall be racked and supported.3.2 Cleaning: Parts shall be cleaned before heat treatment and following heat treatment operations. 3.g. and method of attachment of load thermocouples shall be approved by the cognizant engineering organization. by the sensors or tests used to establish the procedure. oxygen probe) or tests (e.4.1 or at an offset temperature based on the last temperature uniformity survey. in conjunction with the first heat treatment load employing the new atmosphere.2 Personnel: All personnel performing heat treating and associated operations shall be trained and approved in accordance with a procedure such as ARP1962. The offset temperature shall be selected to optimize temperature distribution within the furnace so that the highest and lowest temperatures are equidistant from the specified set temperature. 3.5 Test Methods: The following test methods shall be used.5.1 Suppliers: Facilities performing heat treatment in accordance with this specification shall be approved as specified herein by the cognizant quality assurance organization. 3. 3.3 The efficacy of the purge shall be confirmed. traceable to temperature recorder chart(s).1 Hardness: Shall be determined in accordance with ASTM A 370. microhardness) that are capable of detecting the presence of the previous atmosphere or the resulting contaminant. when applicable: 3.5. and ASTM E 384. -6- . 3. The approximate conversion of tensile strength requirements to hardness shall be in accordance with ASTM A 370. The specific offset shall be posted on the instrument. location.4. unless otherwise specified by the cognizant quality assurance organization. The number. or equivalent documentation such as shop travellers.3.g. ASTM E 10.3. shall be maintained.AMS 2759D SAE AMS 2759D 3.5. 3.6 Loading: Parts shall not be loaded into a furnace with the temperature higher than the set temperature.3. Hardness tests shall be performed on the thickest section.4.3.3. unless load thermocouples are attached to the part to ensure the part temperature does not exceed the set temperature. 3. 3. The offset temperature shall be within ±10 F (±6 C) degrees of the specified set temperature unless the temperature uniformity requirement is less than ±10 F (±6 C). for which the offset temperature shall be within the uniformity range.3..3 Equipment: Equipment used for thermal processing shall be approved to the requirements of this specification and AMS 2750.4 Qualification: 3. as applicable.7 Set Temperature: Control instrument(s) shall be set either at the temperature specified by the procedures listed in 3.2 The purging shall be performed in accordance with a procedure which has been proved effective previously.8 Salt Bath Additives: Shall be limited to the salts in the bath and to additives recommended by the salt manufacturer. ASTM E 18.3.9 Records: A furnace log. 3.. by sensors (e. 2.g. at the loads being used.g. into the salt bath at operating austenitizing temperature for 10 minutes ± 1. A record of the daily checks shall be maintained.4.4. hardness. using standard hardness test blocks for the same scale as. 3. and testing a mechanical property (e. and fast-quench oils.08 mm) thick. or similar (see 8. 3.1 Rockwell.5.g. of appropriate hardenability and dimensions.5. hardness testing machines shall be checked before the first use each day in accordance with ASTM E 18.3. at 500 °F (260 °C)) after quenching to facilitate machining. when required by the cognizant engineering organization.003 inch (0. and shall be shown to be sufficiently sensitive to adequately detect differences in slow-.2.2 Tensile Properties: Testing. in accordance with ASTM E 10.5. 3. 3.1. or entire section of the specimen. 95% martensite on the surface) and significantly less hardening (e. 3.5. A fracture surface showing no evidence of permanent deformation (yielding or taking a set) is acceptable. Brinell machines shall be checked before the first use each day. the hardness of the parts being tested. center.AMS 2759D SAE AMS 2759D 3.2. nominally 0. and within 15 points of.3 Salt Bath Neutrality Test: Immerse a piece of SAE 1095 carbon steel shim. The established method shall be proven to detect changes in speed of the quenchant caused by contamination. medium-.14).5. The specific test shall verify quenchant effectiveness by comparing the tested mechanical property results with those properties listed on the applicable drawing or in the material specification.5.4.3 Testing Area: Tests may be performed on mid-radius.5.1 Specimen Selection for Mechanical Property Tests of all Quenching Media: Selection of the specimen dimensions/hardenability combination should be aimed at achieving approximately full hardening (e. or aqueous polymer quenchant bath shall be monitored using a suitable cooling curve evaluation procedure approved by the cognizant engineering organization. the salt bath neutrality test. 3. Immediately quench the sample in water.g. 3.5.2 Tempering Specimen for Machining: Specimens may be tempered lightly (e. decarburization has occurred and corrective measures to adjust the salt bath are required.1 Comparative Cooling Curve Evaluation: Variation in the quenching effectiveness of an oil. less than 50% martensite plus bainite) at the center. If permanent deformation is noted.4. water.4. 3. strength.2. 3.4 Quench Rate Control: One of the following methods shall be used for the initial and quarterly quench rate tests.2 Mechanical property tests of all quenching media shall be performed by quenching specimens of alloy steel..5. shall be in accordance with ASTM A 370 and ASTM E 8 or ASTM E 8M.1 The tests for surface contamination specified in AMS 2759/1 may be used in lieu of. -7- . Bend the sample until it fractures and examine the fracture surface at approximately 10X magnification.5. and oil temperature changes of 40 °F (22 °C) degrees. modulus) which varies directly or inversely with the effectiveness of quench. and at the same testing frequency as. the maximum tensile strength (converted to hardness) shall be 20.2.2.1.2.5.5. the heat treating processor shall supply all samples for processor's tests and shall be responsible for the performance of all required tests and inspections.3 Modulus: Modulus testing shall be by a dynamic (resonant frequency) method similar to ASTM C 848 or ASTM C 1259.2 Check of hardness testing machines (3. 4. The supplier may use his own facilities or any commercial laboratory acceptable to the cognizant quality assurance organization. 4.0 ksi (207 MPa) above the specified minimum. 3. shall be performed at the frequency specified herein on each piece of equipment in service: 4. 4.1 Acceptance Tests: Hardness (3.1 Daily: 4.5. 3.2. The cognizant quality assurance organization may review heat treating records and the results of tests and inspections to verify that heat treatment conformed to specified requirements.AMS 2759D SAE AMS 2759D 3.5.1 When both the minimum tensile strength and the tempering temperature are specified.1. QUALITY ASSURANCE PROVISIONS: 4.1) and tensile properties.0 ksi (138 MPa) above the specified minimum for strength levels up to and including 260 ksi (1793 MPa) minimum and 25. unless (1) otherwise specified by the cognizant engineering organization or (2) a reduced frequency is permitted by AMS 2750.2) are acceptance tests and shall be performed on each lot. (3.2.6 Additional Processes: Parts shall not be subjected to thermal operations or straightening operations other than those specified.2.1 Responsibility for Inspection: Unless otherwise specified by the cognizant quality assurance organization.5.2. 3. -8- . the maximum strength shall be 30.3) of baths used to heat treat steel to minimum tensile strength of 220 ksi (1517 MPa) and higher.2 Classification of Tests: 4. 4.7 Strength Ranges: When only a minimum tensile strength is specified and the heat treating processor has the option of selecting the tempering or aging temperature.2 Periodic Tests: The following requirements are periodic tests and.0 ksi (172 MPa) above minimum for strength levels over 260 ksi (1793 MPa) minimum. Purchaser reserves the right to sample and to perform any confirmatory testing deemed necessary to ensure that processing conforms to specified requirements. when required.1.4.7.2. unless permitted by the cognizant engineering organization.1).1 Salt bath neutrality test (3. 3) for baths used to heat treat parts to a minimum tensile strength below 220 ksi (1517 MPa).2.2.3.2.2 Salt bath neutrality test (3. except for furnaces used only for annealing.5 Quench rate control tests (3. 4.3. baking. 4.3. as applicable: 4.2.3 Salt content monitoring of water and polymer quenchants (3.2. 4.2. 4.2 Servicing and certification or calibration of Rockwell.5 and 8. 4. and Brinell hardness test machines.2.6 Calibration of Type B and Type C instrumentation at the frequency specified in AMS 2750. 4.2. 4.2.6).4 Certification or calibration of hardness testing machines (3.2.2 Weekly: 4. or similar (see 8.2.5.2.2.2.14). 4.2.5. Annually.2.3 Instrument calibration as in AMS 2750.6.2. 4.2.3.2.5.2. or baking (See 8.4).2 Pyrometer system accuracy test as in AMS 2750.5 Servicing and calibration of atmosphere control measuring equipment at the frequency required in 3. stress relieving. 4.3 Preproduction Tests: The following requirements are preproduction tests and shall be performed prior to any production heat treating for each piece of equipment to be used. the survey shall be at the maximum operating temperature.3 System accuracy tests and instrument calibration of stress relieving and baking equipment as in AMS 2750 (See 8.2. 4.1 Furnace pyrometer system accuracy test (except equipment for stress relieving and baking) as in AMS 2750. 4.3.2.AMS 2759D SAE AMS 2759D 4.4 Temperature uniformity surveys of furnaces as in AMS 2750.1 Calibration of furnace instruments as in AMS 2750.5.5).2.1 Temperature uniformity survey as in AMS 2750. 4.4 Semi-annually: Temperature uniformity survey of annealing. 4. 4.2.2.3. and controlled subzero transformation equipment as in AMS 2750.2.3.2.1.2. stress relieving.2.2.2.2.3.2.2).2.2.2.1).3 Quarterly: 4.7).3. -9- .2.3.2.2.5 Certification or calibration of tensile testing machines (3.2. 5.6 Salt bath neutrality test (3.8.8.2.6).3.1 For Hardness Testing: 4.10 - . 8. 4. 8.2. 2.8 Calibration of atmosphere control measuring equipment (3. NOTES: 1.3 Sampling and Testing: 4. (3) aging.3).4 at AQL of 1. Every part (2).3.10). annealing. solution heat treating. After thermal processes subsequent to shot Not required peening. the requirements of the component specifications shall take precedence.3. .1. for which the frequency of testing is specified. etc (baking after plating.7 Quench rate control test (3. etc) (See 8.3. After thermal processing subsequent to final One part from each lot hardening operation (stress relieving. 4. when required One part from each lot (austenitizing and quenching. etc).Hardness Testing Operation Test Frequency (1) After final operation (hardening and tempering. 4. 4. 4. TABLE 2 .2 When heat treating standard components. plating.2. hot or warm straightening. Statistical sampling is permitted when authorized by the cognizant quality assurance organization or when parts are subjected to 100% testing after thermal processing subsequent to final hardening operation.3. When hardness testing would be destructive or impractical to accomplish. Each detail of a weld assembly shall be considered as a separate part.2.2. the method for verification of correct heat treatment shall be as specified by the cognizant engineering or quality engineering organization.5.11 and 8. When statistical sampling is authorized. etc) (See 8.2.7.3.5 or less. drying.5 and 8.1. normalizing.3. 8.2. such as nuts and bolts.2.2.1 Frequency of hardness testing shall be in accordance with Table 2. 3.2.4).1. etc) (See 8.AMS 2759D SAE AMS 2759D 4.9 and 8. baking prior to plating.2. random samples shall be selected and tested in accordance with ANSI/ASQC Z1. After intermediate operations.2.1. painting.12).3 The test location shall be the thickest or heaviest section of the part which is practical to test and where the test will not be detrimental to the function of the part.6). quench delay.4. stress relieving. The log data shall be recorded in accordance with the heat treater’s documented procedures. alloy.1 Facilities: The approval of a facility shall be in accordance with the following criteria: 4. a lot.4. traceable to temperature recording information (chart(s) or electronic storage media) and to shop travelers or other documentation.1. actual thermal processing times and temperatures used. heat treated to the same property requirements in the same furnace(s) at the same time.1. recorder charts. 4. shall be kept for each furnace and load.2.g. 4. hot or warm straightening) that occur after the final step of the heat operation (e.1.4. tempering.3. baked. shall consist of parts stress relieved. when process parameters are based on thickness. quenchant type. 4.3.4. AMS 2759 or other applicable specification. In addition. fabricated from the same alloy.2 All equipment shall be tested in accordance with this specification and AMS 2750. When testing parts after operations (e. for a continuous furnace.4. shall be recorded and shall be taken as the minimum dimension of the heaviest section of the part. etc using the same equipment at the same time. The information on the combination of documents shall include: equipment identification. and presented for processor's inspection at the same time.2 Personnel: Training and approval of personnel shall be in accordance with 3. The maximum thickness.11 - . The records shall contain all data necessary to verify conformance to specified requirements.g. hot or warm straightened. aging). number of parts. date. in addition to the above.4 Approval: 4. all other shop records.6 Records: Furnace logs. It shall consist of a full description of all equipment and procedures that will be used to process parts to this specification and the applicable specifications listed in 3. and all test and inspection records shall be kept available to the cognizant quality assurance organization for five years after heat treatment. When applicable. 4. part number or product identification. it shall be those parts heat treated as a continuous production run during an eight-hour shift.AMS 2759D SAE AMS 2759D 4. 4. polymer concentration and quenchant temperature shall also be recorded. baking. approved personnel’s identification.2 Lot: Shall be all parts of the same design.1 The heat treating processor shall have a copy of his shop procedure available for the cognizant quality assurance organizations. lot identification. . atmosphere control parameters.5 Logs: A record (written or electronic storage media). This data shall be reported in accordance with the heat treater’s documented procedures. part number or product identification.g. shear etc. identification of furnace(s) used. quantity of parts in the shipment. REJECTIONS: Parts not heat treated in accordance with this specification. packaging. alloy. (e.1 Identification: Identification of parts or product provided to the heat treat processor shall be maintained on the parts at delivery. and transportation of the parts to ensure carrier acceptance and safe delivery.2. hot straightening temperature and method of straightening (e. 5. the report shall also include: atmosphere type.3 Packages of parts shall be prepared for shipment in accordance with commercial practice and in compliance with applicable rules and regulations pertaining to the handling.AMS 2759D SAE AMS 2759D 4. hardness. ACKNOWLEDGMENT: A vendor shall mention this specification number and its revision letter in all quotations and when acknowledging purchase orders. with each shipment of parts. quenchant (including polymer concentration range).) and a statement of their conformance/nonconformance to requirements.1 When specified by the procuring activity. The report shall include: purchase order number.2 Parts shall be packaged to ensure protection from damage during shipment and storage. 5.2 Packaging: 5. stating that the parts were processed in accordance with the requirements of AMS 2759D (or other applicable specification). or with modifications authorized by the cognizant engineering organization. 5. actual thermal processing times and temperatures used.2.12 - . When applicable. actual test results.7 Report/Certification: The heat-treating processor shall furnish. 6. a certified quality assurance report. fixtures). temper/strength designation. PREPARATION FOR DELIVERY: 5..g. 7. will be subject to rejection and shall be submitted for disposition in accordance with purchaser's procedures for nonconformance. . press. tensile. 5.2. parts shall be protected with corrosion preventive compounds when shipped. conductivity. traceable to the heat treat control number(s). Change bars and (R) are not used in original publications.2 Terms used in AMS are clarified in ARP1917 and as follows: 8. etc) in order to remove hydrogen from the parts.2. including technical revisions. nor in specifications that contain editorial changes only. etc temperature. followed by quenching to develop a martensitic structure suitable for tempering to desired properties. usually followed by air cooling through the martensite range to ambient temperature. 8.2. usually for subsequent forming. the martensite range and holding until temperature uniformity throughout the part is obtained. or slightly above. An (R) symbol to the left of the document title indicates a complete revision of the specification. it is done below the tempering. aging. 8.2.AMS 2759D SAE AMS 2759D 8. in order to relieve residual stresses caused by working or thermal cycling. soaking at temperature. not editorial changes.5 Stress Relieving: Heating parts. 8. it shall be located in the slowest heating part of the furnace which contains the heaviest section of the parts.2. plating. The term “annealing” means “full annealing”.1 Parts: Finished and semi-finished parts.2.9 Tempering: Heating of the martensitic structure developed by hardening to an intermediate temperature to develop a specific combination of strength and ductility. . When performed after the final heat treating operation.1 A change bar (l) located in the left margin is for the convenience of the user in locating areas where technical revisions.2. or its allied quality assurance organization. have been made to the previous issue of this specification.13 - .4 Cognizant: The term applied to the engineering organization responsible for the design of the parts.2 Load Thermocouple: A thermocouple attached to and in direct contact with the heaviest section of a part or representative sample.2. including raw mill products. Where possible.2. such as pickling. 8. 8.3 Marquenching (Martempering): Quenching an austenitized alloy in a salt or hot oil bath at a temperature in the upper part of.6 Baking: Heating parts (which are in the final heat treated condition and have been subjected to an embrittling operation. There should be no gap between the thermocouple and the part. heat treated by the user during the fabrication process or for qualification of response to heat treatment. aging.2. 8. before or after the final heat treating operation. etc temperature.8 Hardening: Heating to a suitable temperature above the austenite transformation temperature (austenitizing). It should be shielded against furnace radiation and protected against contamination from the furnace atmosphere or heating medium.7 Annealing: Heating to a suitable temperature. 8. 8. or a designee of these organizations. 8. and slow cooling in order to get the part in its softest possible condition. This operation is normally performed at 375 °F (191 °C) but is always at a temperature lower than the tempering. NOTES: 8. AMS 2759D SAE AMS 2759D 8.6 Similar Specifications: This specification. or condition to which parts are to be heat treated.4 Dimensions and properties in inch/pound units and the Fahrenheit temperatures are primary.13 Thickness: The minimum dimension of the heaviest section of the part. when used in conjunction with the detail specification for the specific process in 3.14 - .10 Aging (Precipitation Hardening): Heating to an intermediate temperature to cause precipitation of constituents within the material which will produce an increase in strength and hardness.3 Although the results of both tests and production experience have shown that polymer quenchants can be successfully substituted for oil quenchants for even highly hardenable steels. 8. 8.2. 8. the wide difference of cooling characteristics achieved with different types of polymers and concentration levels requires that the validation procedure be targeted specifically toward the intended polymer/ concentration.2.11 Normalizing: Heating to a suitable temperature above the austenite transformation temperature and air cooling to develop a uniform structure. followed by cooling to hold one or more elements in solution for subsequent precipitation hardening. 8.2. hardness.5 Purchase documents should specify not less than the following: AMS 2759D Size of parts Quantity of parts Part number or product identity Material alloy designation of parts Heat treating operations desired Tensile strength. dimensions and properties in SI units and the Celsius temperatures are shown as approximate equivalents of the primary units and are presented only for information. 8.12 Solution Heat Treating (Solution Annealing): Heating to a sufficiently high temperature. 8. 8. exceeds the minimum requirements of the current revision of MIL-H-6875 and AMS-H- 6875 for heat treatment of parts.2. PREPARED UNDER THE JURISDICTION OF AMS COMMITTEE “E” AND AMEC .14 Rockwell: Hardness testing performed in accordance with ASTM E 18. 8.1.2.3.