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1、GLOBAL STANDARDGS-0062.A Page 1of 22 Master Document: Global Heat-Treat Standard Standard No.: GS-0062 Revision level: ARevision date: 2006-10-24 Author: David Wills Process owners/ Reviewers: Greg Shen, Milan Sukovsky, Tom Loegstrup, Patrick Bicard, Roman Torbus, Stanislawa Wontor, Wilfried Weiss,
2、Wilhelm Lindert Administrator: Christine Holst Approved by: (Process owner) Doug McCoy Date: 2006-10-26Local Edition: Language: Author: Process owners/ Reviewers: Administrator: Approved by : Date: (YYYY-MM-DD) Auxiliary tools: Changes in relation to previous issue are written with red, alternativel
3、y for figures and tables with a red frame around. GLOBAL STANDARDGlobal Heat-Treat Standard GS-0062.A Page 2 of 22 1CONTENTS 2.Scope 3.Purpose 4.Related Documents 5.Equipment and Pyrometry 6.General Heat-Treat Requirements 7.Through-Hardening 8.Gas Carburizing 9.Gas Nitriding 10.Carbonitriding 11.Ga
4、seous Nitrocarburizing 12.Salt Bath Nitrocarburizing 13.Induction Hardening 14.Hydrogen Embrittlement Relief 15.Heat-Treat Personnel Qualifications 16.Testing Requirements 17.Test Report Requirements 18.General Operating System Requirements 19.Appendix A: General Notes 20.Appendix B: Thickness Limit
5、s for Surface Hardness Measurements of Surface Treated Materials 21.Appendix C: Case Depth Determination According to DIN 50190 22.Appendix D: Chart Showing Visual Estimation of Per Cent Retained Austenite 2SCOPE This standard establishes general requirements for heat treatment of steel parts by Sau
6、er-Danfoss heat-treat sites and Sauer-Danfoss suppliers and forms an integral part of Sauer-Danfoss detail specifications and engineering prints. When there is a conflict between this standard and the detail specification or the drawing, the drawing shall take precedence first and the detail specifi
7、cation second. Global standards for SQAs, PPAP s, and PFMEA s are an important and integral part of high quality heat treatment, but are not within the scope of this document. 3PURPOSE This standard specifies the minimal requirements for inspection methods, process controls, heat-treat equipment, an
8、d general operating procedures necessary to produce heat treated parts free from defects. This standard is intended as a supplement to the industry standards referenced throughout this document. As a standard, the practices defined in this document should be considered as requirements for Sauer-Danf
9、oss and external heat treating facilities. In cases where a U.S. standard is specifically cited, an equivalent European standard may be substituted. GLOBAL STANDARDGlobal Heat-Treat Standard GS-0062.A Page 3 of 22 4RELATED DOCUMENTS The following documents are referenced herein: SAE and AMS Publicat
10、ions are available from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001. ASTM Publications are available from ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959. ASTM E384 Microhardness of Materials ASTM E10 Brinell Hardness of Materials ASTM E18 Rockwell Hardness and Rockwell Supe
11、rficial Hardness of Metallic Materials ASTM E92 Test Method for Vickers Hardness of Metallic Materials SAE J423 Case Depth Measurement AMS 2759C Heat Treatment of Steel Parts (General Requirements) AMS 2759/1 Heat Treatment of Carbon and Low Alloy Steel Parts - Minimum Tensile Strength Below 220 KSI
12、 (1517 Mpa) AMS 2759/2 Heat Treatment of Low Alloy Steel Parts - Minimum Tensile Strength 220 KSI (1517 Mpa) and Higher 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 2759/9 Hydrogen E
13、mbrittlement Relief (Baking) of Steel Parts AMS 2757 Gaseous Nitrocarburizing ARP 1962 Training and Approval of Heat Treating Personnel AMS H 6875 Heat Treatment of Steel Raw Materials AMS 2750 Pyrometry ARP 1820 Chord Method of Evaluating Surface Microstructural Characteristics SAE J864 File Hardne
14、ss Measurement Method ASTM E1417 Standard Practice for Liquid Penetrant Testing ASTM E1444 Standard Practice for Magnetic Particle Testing ASTM E709 Standard Guide for Magnetic Particle Examination In addition to the standards specifically referenced by this document, sections 4.1 4.5 of this docume
15、nt serve as a cross-reference by heat-treat process of the U.S. and European industry standards. 4.1General Heat-Treat Requirements Process Description of the Standard ASTM/SAE/AMS/ARP Nr. DIN/EN/ISO Nr. General Heat Treatment Heat Treatment of Steel Parts Practice of Heat Treatment Heat-Treat Proce
16、sses of Iron Materials AMS 2759 AMS 2759 AMS 2759 DIN 6773/1-5 DIN 17022-1 DIN 17014-3 GLOBAL STANDARDGlobal Heat-Treat Standard GS-0062.A Page 4 of 22 4.2Heat-Treat Equipments Process Description of the Standard ASTM/SAE/AMS/ARP Nr. DIN/EN/ISO Nr. Heat-Treat Equipment Industrial Temperature Uniform
17、ity Requirements Flame Control with Gas Equipment Industrial Quench Oils Pyrometry AMS 2750 AMS 2759 AMS 2750 DIN 17052 DIN 16160 DIN 3258 ISO 9950 DIN 24201 4.3Heat-Treat Processes Process Description of the Standard ASTM/SAE/AMS/ARP Nr. DIN/EN/ISO Nr. Harden and Tempering Heat Treatment of Carbon
18、and Low Alloyed Steel Parts below 220KSI/151MPa Heat Treatment of Low Alloyed Steel Parts below 220KSI/151MPa Heat Treatment of Steel Raw Material Practice of Heat Treatment Heat-Treat Processes of Iron Materials Assortment Based on the Harden-ability AMS 2759-1 AMS 2759-2 AMS H 6875 AMS 2759 DIN 17
19、022-1 DIN 17022-1 DIN 17022-1 DIN 17022-1 DIN 17021-1 Carburizing Gas and Vacuum Carburizing and Heat Treatment of Carburizing Grade Steel Parts Heat Treatment Carburizing AMS 2759-7 DIN 17022-3 Nitriding Gas Nitriding and Heat Treatment of Low Alloyed Steel Parts Gaseous Nitrocarburizing AMS 2759-6
20、 AMS 2757 DIN 17022-4 Inductive Hardening Surface Hardening Treatment DIN 17022-5 Heat Treatment of Tools Heat Treatment of Tools DIN 17022-2 Documentation Technical Product Documentation Heat Treated Ferrous Parts ISO 15787 GLOBAL STANDARDGlobal Heat-Treat Standard GS-0062.A Page 5 of 22 4.4Test Re
21、quirements Process Description of the Standard ASTM/SAE/AMS/ARP Nr. DIN/EN/ISO Nr. Macro Hardness MeasurementStandard Test Method for Brinell Hardness of Metallic Materials Standard Test Method for Vickers Hardness of Metallic Materials Rockwell Hardness and Rockwell Superficial Hardness of Metallic
22、 Materials ASTM E10 ASTM E92 ASTM E18 EN 6506-1,2,3 EN 6507-1,2,3 EN 6508-1,2,3 Micro Hardness Measurement Evaluation of the Case Depth after Surface Hardening Evaluation of the Case Depth after Carburizing Evaluation of the Case Depth after Nitriding Evaluation of the Case Depth of Case Hardened Po
23、wder Material ASTM E384, SAE J423, ARP 1820 ASTM E384, SAE J423, ARP 1820 ASTM E384, SAE J423, ARP 1820 ASTM B721DIN 50190-2 DIN 50190-1 DIN 50190-3 DIN 30911-5 DIN ISO 4507 ISO 4498/2/00 Special Checks Magnetic Particle Inspection Liquid Penetrant Testing Pyrometry Chord Method of Evaluating Surfac
24、e Microstructural Characteristics Microscopic Examination of Carbide Structure in Steels by means of Diagram Series Hydrogen Embrittlement Relief (Baking) of Steel Parts ASTM E1444, ASTM E709 ASTM E1417 AMS 2750 ARP 1820 AMS 2759-9 DIN/EN/ISO 3059 EN 571-1 DIN/EN 3452 SEP 1520 GLOBAL STANDARDGlobal
25、Heat-Treat Standard GS-0062.A Page 6 of 22 4.5Education and Training Process Description of the Standard ASTM/SAE/AMS/ARP Nr. DIN/EN/ISO Nr. Education and Training Training and Approval of Heat Treating Personnel Heat-Treat Processes of Iron Materials Forms and Heat-Treat Instructions Items of Heat-
26、Treat Processes of Iron Materials Ferrous Products Heat Treatment Vocabulary ARP 1962 DIN 17023 EN 10052 DIN 17014 ISO 4885 5 EQUIPMENT AND PYROMETRY Thermal processing equipment and related pyrometric equipment shall be controlled in accordance with AMS 2750 (DIN/EN 3452). Heating EquipmentAutomati
27、c temperature controllers and data recording instruments conforming to AMS 2750 (DIN/EN 3452) are required on each furnace. Instrumentation, thermocouples, test equipment accuracy shall conform to AMS 2750 (DIN/EN 3452). Equipment which cannot be controlled and tested in accordance with AMS 2750 (DI
28、N/EN 3452) shall be controlled and tested as directed by Metallurgy. Quenching Equipment Quench baths shall permit complete immersion of parts, shall have a temperature indicator with a sensor in the quench media, and shall be free from visible contamination, which could detrimentally affect the pro
29、cess. Tanks with oil should be equipped with a device forcing oil circulation for better heat exchange during quenching. Bath maintenance programs shall be established and when using polymers, a concentration control system shall be established. Quenching Media Except when marquenching, the temperat
30、ure of the bath shall insure the proper cooling speed to produce a microstructure that will meet property requirements of the final part specification. GLOBAL STANDARDGlobal Heat-Treat Standard GS-0062.A Page 7 of 22 6GENERAL HEAT-TREAT REQUIREMENTS Preheating Preheating between 900 to 1200 F (482-6
31、49 C) is recommended before heating parts above 1300 F (704 C) if the parts have been previously hardened to 35 Rc (345 VHN 10 Kg) or greater, or if geometry of the part may produce excessive stresses during heat up. When preheating parts above 570 F (300 C), a protective atmosphere is recommended t
32、o reduce surface oxidation. Air, without a protective atmosphere, is acceptable when preheating parts below 570 F (300 C). Soaking Soaking shall commence when the control thermocouple reaches the specified set temperature. Tempering Tempering shall occur within 4 hours of quench. Soaking time shall
33、not be less than 2 hours plus one hour additional for each inch of thickness or fraction thereof greater than 1 inch. Parts may be snap tempered for 2 hours at a temperature that is lower than the tempering temperature. Straightening For parts having a minimum tensile strength below 180 KSI (40 Rc)
34、or 1241 MPa (392 VHN), straightening may be accomplished without stress relieving. For parts having a minimum tensile strength of 180 KSI (1241 MPa) or above and straightened at room temperature, straightening shall be followed by stress relieving at a temperature not higher than 50 F (28 C) below t
35、he tempering temperature. Cleaning The heat-treat department should receive clean parts. Parts shall be cleaned prior to heat treatment only if it is necessary to remove contaminants that could have a deleterious effect on the surface visual appearance, surface microstructure, or part performance. C
36、leaning after heat treatment (quenching) should be performed as necessary to ensure the parts meet cleanliness requirements. Masking Coatings or plating used for the protection of surfaces during heat treatment shall be approved by Metallurgy. The type of masking used shall be reviewed to ensure tha
37、t the furnace atmosphere is not contaminated by its use. Spacing/Racking Parts shall be racked and supported primarily to ensure access of the heating atmosphere and quenching media to all surfaces of all parts and secondarily to minimize distortion. GLOBAL STANDARDGlobal Heat-Treat Standard GS-0062
38、.A Page 8 of 22 7THROUGH-HARDENING Quenching and Tempering Quenching and tempering shall be in accordance with ASTM 2759/1 and ASTM 2759/2. The heating atmosphere shall be neutral to the surface of the steel being treated to prevent decarburization or carburization of the steel surface. Decarburizat
39、ion For parts heat treated to 220 KSI (46 Rc) or 1517 MPa (458 VHN) and above, the depth of decarburization (complete decarb is not permitted) after all heat-treat operations shall not exceed 0.003 inches (0.08 mm) on any surface. For parts heat treated to less than 220 KSI (46 Rc) or 1517 MPa (458
40、VHN), the depth of partial decarburization (complete decarburization not permitted) after all heat-treat operations, shall not exceed 0.005 inches (0. 13 mm). The depth of decarburization shall be determined by making a microhardness traverse per ASTM E384 (DIN 50190 1-3), using at least 250X magnif
41、ication and recording hardness versus depth below the surface. The boundary of decarburization shall be the point at which the Knoop or equivalent hardness is 20 points (approximately 18 VHN points) less than the base hardness. Carburization or nitriding In through-hardened parts, furnace atmosphere
42、s which increase the Carbon content of surfaces above the maximum for the respective composition and/or increase the surface hardness 20 points Knoop or equivalent (approximately 18 VHN points) above the core hardness, are not acceptable. In addition, the microstructure shall not show any evidence o
43、f carburization or nitriding. Intergranular attack Intergranular oxidation, as determined by metallographically etching specimens, shall not exceed .0005 inches (0.013 mm) on parts heat treated to 220 KSI (46 Rc) or 1517 MPa (458 VHN) and above, and .0007 inches (0.018 mm) on parts heat treated to l
44、ess than 220 KSI (46 Rc) or 1517 MPa (458 MPa). Core hardness Core hardness shall be determined in the most massive or functional section of the part unless specified otherwise. 8GAS CARBURIZING Gas carburizing shall be in accordance with AMS 2759/7 (DIN 17022-3). Case Carbon Content Surface carbon
45、of finished heat treated parts shall be 0.70 to 1.00%. The surface carbon content of parts in process may exceed 1.00% when boost and diffuse processes are being utilized, such as with vacuum and plasma carburizing. GLOBAL STANDARDGlobal Heat-Treat Standard GS-0062.A Page 9 of 22 Case Microstructure
46、 Retained austenite shall not exceed 15% unless specified otherwise on the engineering print or heat-treat process instructions. Retained austenite shall be determined by visual comparison (See Appendix D: Martensite/Austenite Chart) unless x-ray diffraction is required by the engineering print or h
47、eat-treat process instructions. When x-ray diffraction is required, the method used shall be agreed upon between the heat-treater and the customer. Intergranular (grain boundary) carbides shall be scattered and discontinuous and shall not be evident in more than (30%) of the grain boundaries (See Ph
48、otograph 5.2 in SEP 1520). Case microstructure shall be predominantly tempered martensite. Intergranular oxidation shall not exceed 0.0005 inches (0.013 mm) in depth from the unmachined surfaces. Case Hardness Case hardness shall be 58-62 Rc (653-746 VHN) and shall be determined in accordance with A
49、STM E18 (EN 6508 -1,2,3) on the carburized and hardened surface of the finished part using a superficial hardness test appropriate for the depth of case specified (See Appendix B ). Case Depth (effective case depth) see section 20 for detailed instructions Effective case depth is defined as the dept
50、h below the surface of the part where the hardness is equal to or greater than 50Rc (513 VHN) as measured by a microhardness survey in accordance with ASTM E384 or DIN 50190. Note that DIN 50190 limiting hardness (LH) is 550 VHN (52.5 Rc) - See Appendix C. Effective case depth shall be determined by
51、 optical method measurement on a metallographically polished and etched (4% nital) sample when the core hardness exceeds 45 Rc (446 VHN). In applying the optical method, the effective case depth shall be defined as the depth of the midpoint of the microstructural transition zone laying between the h
52、igher carbon outer surface and the low carbon core. Total Case Depth Total case depth is the depth from the surface to the point where core microstructure characteristics and case structure characteristics can no longer be differentiated. This point can be determined by hardness gradient, microstruc
53、ture changes, or carbon concentration gradient. Quenching Parts may be direct quenched (cooled to austenitizing temperature prior to quenching) rather than being slow cooled to room temperature and rehardened. Selective Carburizing Selective carburizing may be accomplished by masking. Unless specifi
54、ed otherwise, threaded ends of shafts shall be masked prior to carburizing. For Gears and Splines For gears and splines, the case depth applies to the teeth surfaces at the pitch diameter. Case depth at the root of the gear teeth and root of the spline teeth shall not be less than 75% of the minimum
55、 specified case depth. Surface hardness of gear and spline teeth roots GLOBAL STANDARDGlobal Heat-Treat Standard GS-0062.A Page 10 of 22 may be 1 point Rc (approximately 20 VHN points) lower than that specified at the pitch diameter. 9GAS NITRIDING Gas nitriding shall be in accordance with AMS 2759/
56、6 (DIN 17022-4). Equipment Equipment shall be available for introducing ammonia into the furnace at a controlled rate. A separate system for ammonia dissociation is recommended. Where ammonia dissociation is used, the equipment shall be capable of maintaining the atmosphere within +/- 5% of the sele
57、cted percent dissociation. Decarburization/Contamination Surfaces to be nitrided shall be free from decarburization and contaminants such as grease, oil, and scale, which could interfere with nitrogen diffusion. Stress Relieving Unless otherwise specified, parts which have been ground or otherwise m
58、echanically worked after hardening, shall be stress relieved prior to nitriding. The stress relieving temperature shall not be greater than 50F (28 C) below the tempering temperature (where applicable). Nitriding TemperatureUnless specified otherwise, the nitriding temperature range shall be 940-105
59、0 F (504-566 C) and should not be greater than 50F (28 C) below the tempering temperature. Microstructure The microstructure shall exhibit a uniform distribution of nitrides diminishing gradually from the surface to the core. There shall be no evidence of a continuous nitride network in grain bounda
60、ries. Unless otherwise specified, the maximum thickness of the compound zone (white layer) shall be 0.001 inches (25 m). Case Depth Unless otherwise specified, case depth requirements shall be interpreted as either total case depth (compound + diffusion zone) or depth of the compound zone only. Tota
61、l case depth is the depth of the continuous etching subsurface zone, determined metallographically on the as-nitrided part using 4% nital etching solution. On those materials that do not respond to etching, the total case depth is the depth below the surface at which microhardness is 50 HVN higher t
62、han that of the core, as determined by a Knoop or Vickers hardness traverse, in accordance with ASTM E 384. Effective case depth, where specified, shall be in accordance with drawing requirements and is the depth to which a specified hardness in accordance with ASTM E 384 or DIN 50190-2 is attained.
63、 Case depth defined by DIN 50190-2 is core hardness + 50HV0.5 (See Appendix C). GLOBAL STANDARDGlobal Heat-Treat Standard GS-0062.A Page 11 of 22 Surface Hardness Surface hardness shall be determined by Rockwell superficial hardness or microhardness in accordance with ASTM E 18, ASTM E 92, or ASTM E
64、 384 (EN 6056 -1,2,3 or DIN 50190 -1,2,3). See Appendix B for description of thickness limits versus hardness method and test load. Compound zone hardness may be verified with the use of hardened files calibrated in increments of 5 points Rc (approximately 100 VHN). Surface Finish Effect The capabil
65、ity of a surface to accept a nitride case is influenced by its surface finish. Burnished, polished, and work hardened surfaces in general will not nitride satisfactorily. Abrasive blasting of all surfaces is recommended prior to nitriding. 10 CARBONITRIDING Microstructure Case microstructure shall b
66、e in accordance with the requirements of gas carburizing in section 8. Additionally, excessive nitride needles shall not be present when examined at a magnification of 500X. Case Depth and Hardness Definition and determination of carbonitrided case depth and hardness shall be in accordance with the
67、methods used for gas carburizing in section 8. 11 GASEOUS NITROCARBURIZING Gaseous nitrocarburizing shall be in accordance with AMS 2757 (DIN 17022-4) and shall consist of a continuous thin epsilon-iron-carbonitride compound layer. Basically, the nitrocarburizing process is a thermochemical treatmen
68、t carried out in a gaseous media, which involves diffusional additions of both nitrogen and carbon to the surface of ferrous materials at temperatures within the stress relief range. The primary objective is to provide an improved wear and fatigue resistant surface to carbon steel, alloy steel, and
69、cast iron parts. Because the tempering is carried out at temperatures below 1200F (649 C), retention of core properties and good dimensional control are achieved. An additional benefit of improved corrosion resistance, through the formation of a continuous compound layer on the surface, can eliminat
70、e the need for protective plating. Hardening Parts where core hardening is specified shall be tempered at a temperature not less than 50 F (28 C) above the nitrocarburizing temperature. Stress Relieving Parts which have been machined or straightened prior to nitrocarburizing, may be stress relieved
71、at a temperature not less than 40 F (20 C) above the nitrocarburizing temperature. GLOBAL STANDARDGlobal Heat-Treat Standard GS-0062.A Page 12 of 22 Quenching A range of properties can be obtained by controlling the rate of cooling from the treatment temperature. Parts may be quenched in oil, water,
72、 soluble oil solutions, aqueous polymer solutions, inert or nitrocarburizing atmospheres, or air. Depth of Compound Layer The depth of compound layer shall be determined in accordance with the procedure of SAE J423 (DIN 50190 -1,2,3) or ARP 1820 microscopic methods, at not less than 500X magnificati
73、on. Typical compound depth range for carbon steel, low alloy steel, and cast iron is 0.00015 inch (0.00038 mm) to 0.0010 inch (0.025 mm). Presence of Compound Layer The presence of a compound layer shall be confirmed by means of a chemical spot test. A drop of copper ammonium chloride (see section 1
74、8, note 1) or copper sulfate solution (see section 18, note 2) applied to a clean nitrocarburized surface of a part shall turn a reddish brown color after 15 seconds. If copper plates out on the surface, the compound layer is not present. Compound Layer Hardness The layer hardness shall be the equiv
75、alent of 60 Rc (697 HV10) or greater determined in accordance with SAE J864 for file hardness. Microhardness testing of the surface may be done in accordance with engineering print and /or specification requirements. Diffusion Zone Hardness Diffusion zone hardness when required by specification and/
76、or engineering print shall be determined by microhardness measurements in accordance with ASTM E384 (DIN 50190-2) or by the chordal method of ARP 1820. Diffusion Zone Depth Diffusion zone depth, when required by specification and/or engineering print, shall be determined in accordance with ASTM E384
77、 (DIN 50190-2) and is defined as the depth at which the hardness gradient exceeds the core hardness by 50 HV 0.5Kg (approximately 5 Rc). See Appendix C. Compound Layer Structure The compound layer microstructure, when viewed at 500X in a representative field in the upper half of the compound zone, s
78、hall not contain a level of porosity and oxides greater than the amount stated in the specification. The compound layer at the substrate interface shall not exhibit residual porosity and oxides exceeding 5% for steel and 15% for cast iron. Although it is expected that the compound layer will consist
79、 primarily of epsilon iron nitride, the specific mix of epsilon and gamma prime may be specified by specification and/or engineering print. GLOBAL STANDARDGlobal Heat-Treat Standard GS-0062.A Page 13 of 22 12 SALT BATH NITROCARBURIZING There are several versions of salt bath nitrocarburizing that ar
80、e capable of providing similar compound and diffusion layers with similar properties to that achieved by the gaseous process. A few of these industrial processes are: Tennifer QPQ and Melonite QPQ. The requirements listed under gaseous nitrocarburizing in section 11 apply to relevant salt bath nitro
81、carburizing process quality demands. Salt bath nitrocarburizing temperatures must be greater than gas nitrocarburizing temperatures, which are typically 570-590C (1058-1094F). 13 INDUCTION HARDENING Induction hardening is a process in which high frequency electromagnetic radiation is coupled to the
82、steel part, producing induced currents that cause the heating in the steel. Heating of the steel does not occur just on the surface, but also in the surface layers. The depth of heating is related inversely to the frequency, in that higher frequency produces heating to a shallower depth. The primary
83、 objective of induction heating is to provide an improved wear and fatigue resistant surface for carbon steel, alloy steel, and cast iron parts. This is accomplished by heating above the AC3 and quenching to produce a hardened surface and an accompanying residual compressive surface layer. The equip
84、ment used to heat-treat a component shall be fully capable of processing the part with adequate controls on power levels, heat times, quench times, quench temperature, and other key processing parameters. Key Parameters and Controls The key parameters of an induction hardening process are: machine s
85、etting, frequency, energy, cooling, tool setting, temperature and concentration of quench media. The heat-treater should have a documented plan for controlling each of these parameters. Surface Hardness The surface hardness specified on the engineering print shall be measured directly on the part su
86、rface in accordance with ASTM E18 (EN 6508 1,2,3), using the appropriate hardness scale compatible with the induction hardened depth. See Appendix B for description of thickness limits versus hardness method and test load. Surface hardness may also be measured on a sectioned sample at .003 inches (0
87、.075 mm) per ASTM E384 (DIN 50190-3). Depth of Hardening The case depth specified on the engineering print or heat-treat specification will normally be described in terms of the depth at which a minimum hardness is attained in accordance with microhardness testing per ASTM E384 (DIN 50190-3). Effect
88、ive case is defined as the depth at which the hardness is 10 points Rc (approximately 120 VHN) less than the required minimum surface hardness (or 80% of the required minimum surface hardness as per DIN 50190-3) - See Appendix C. For example, for high carbon steel with a minimum surface hardness req
89、uirement of 60 Rc (697 VHN), 50 Rc (513 VHN) defines the effective case depth. For medium carbon steels with a minimum surface hardness requirement of 50 GLOBAL STANDARDGlobal Heat-Treat Standard GS-0062.A Page 14 of 22 Rc (513 VHN), 40 Rc (392 VHN) defines the effective case depth. Total case depth
90、, if required, is the depth at which core microstructure characteristics and case microstructure characteristics can no longer be differentiated. Total case depth may also be defined as the depth at which the hardness gradient exceeds the core hardness by 50 HV0.5Kg (approximately 5 Rc). Induction H
91、ardening Pattern The area to be selectively induction hardened shall be defined on the engineering print or heat-treat specification. Unless specified otherwise, induction hardened surfaces may be bordered by a transition zone of up to 0.500 inches (12.70 mm) maximum. This transition zone is a regio
92、n beyond the intended process zone and is characterized by hardness values less than those of the unheated base metal. Note that this transition (Heat Affect Zone - see definition of Heat Affect Zone - HAZ, in section 18, note 5) may contain residual tensile stresses that can potentially impact fati
93、gue life of the component, so that the location of this zone can be extremely critical to the expected life of the component. It is recommended for good design practice that the HAZ should not exceed ? the distance from the surface to the midpoint of the section being hardened. Microstructure after
94、Induction Hardening Microstructural examination performed at 500X in the effective case depth region of the induction hardened and quenched and tempered part shall show a uniformly tempered martensitic microstructure. There shall be no evidence of over or under heating as revealed by incipient melti
95、ng, retained austenite in excess of 15% (unless specified otherwise on the part drawing) and/or free ferrite. Microstructure prior to Induction Hardening It is recommended that the microstructure of carbon steel, alloy steel, and cast iron contains a minimum of 80% pearlite (predominantly lamellar o
96、r globular, mixed not acceptable) or 90% martensite prior to induction hardening to insure a rapid and uniform heat-treat response. Area Selected for Examination The area selected for examination of the pattern should represent the full pattern area. Examination with respect to surface hardness, dep
97、th of hardening, and microstructure should be located in the center of the pattern, unless specified otherwise. First-piece inspection is required in an induction hardening process. The heat-treater should have the capability of inspecting for cracks. Tempering Parts shall be tempered at a minimum t
98、emperature of 351 F (177 C). Although not the preferred method, induction tempering is allowed provided a suitable method has been demonstrated to achieve the print hardness requirement. Timing between induction hardening and tempering is critical, but it can vary by application. The time should be
99、controlled to avoid cracking. GLOBAL STANDARDGlobal Heat-Treat Standard GS-0062.A Page 15 of 22 14 HYDROGEN EMBRITTLEMENT RELIEF BAKING Hydrogen relief baking of steel parts shall be in accordance with AMS 2759/9. Relief baking is performed to remove hydrogen infused during plating and other chemica
100、l processes such as stripping, chemical milling, pickling, de-burring, and etching. This relief baking is the responsibility of the facility performing the surface treatment. Parts to be Baked Hydrogen relief baking is applicable to parts made from carbon, low-alloy steel, and martensitic stainless
101、steel (including precipitation hardened stainless) heat treated to a minimum strength of 180 KSI (1241 MPa) or heat treated to a minimum hardness of 40 Rc (392 VHN) or equivalent. It is also applicable to threaded fasteners heat treated to a minimum strength of 150 KSI (1034 MPa) or 34 Rc (336 VHN)
102、or equivalent hardness, and steel parts which have been surfaced hardened (carburized, nitrided, carbonitrided, nitrocarburized, or induction hardened). Supplier should be aware that parts with a minimum strength even as low as 117 KSI (800 MPa) or minimum hardness of 22 Rc (250 VHN) may be suscepti
103、ble to hydrogen embrittlement and should take proper precautions. Baking Requirements Parts shall be baked after completion of each plating or other chemical process in accordance with the requirements of Table 1 of AMS 2759/9. Baking is not required between steps in a multiple step (plating/chemica
104、l process) sequence if interruptions do not exceed 2 hours, baking is started within 4 hours after the final step, and total time between start of first step and start of baking does not exceed 24 hours. When baking is required between steps, the minimum soaking time may be reduced to 3 hours for pa
105、rts 240 KSI (1655 MPa) or a minimum of 49 Rc (498 VHN) or equivalent. For higher strength parts the soaking time shall be a minimum of 6 hours. Nickel plated parts are an exception and shall be soaked for the required times of Table 1 of AMS 2759/9 for parts heat treated to a minimum strength of 200
106、 KSI (1379 MPa). Baking Procedure The elapsed time between completion of plating or other chemical processing and baking shall not exceed 4 hours. The standard baking temperature is 375 F (191 C). The baking temperature for parts that are carburized or carbonitrided shall be 275 F (135 C). The bakin
107、g temperature for parts made from 52100 and 440C that have been heat treated to a minimum strength of 220 KSI (1517 MPa) or a minimum hardness of 46 Rc (458 VHN) shall be 300F (149 C). The baking temperature for parts made from music wire is 325 F (163 C). Minimum baking times shall conform to Table
108、 1 of AMS 2759/9. Typical baking times are either 8 hours or 23 hours depending on material, how material is processed, and plating process or chemical treatment. 15 HEAT-TREAT PERSONNEL QUALIFICATIONS All personnel performing heat treating and associated operations shall be trained and approved in
109、accordance with ARP 1962 (see 4.5 Table for DIN equivalent). GLOBAL STANDARDGlobal Heat-Treat Standard GS-0062.A Page 16 of 22 16 TESTING REQUIREMENTS Testing Capabilities and Requirements Heat treating facilities shall have the testing equipment necessary to perform the tests to verify conformance
110、to requirements. Those measurements that are performed infrequently may be sourced to an outside laboratory. Preproduction tests Prior to the first shipment of a new part number, a significant process or product change, or shipment of a previously existing part number to a new customer, the appropri
111、ate testing should be performed as per the design specification (and PPAP material test requirements) to verify the appropriate material and process to meet the application intent. Acceptance/Production (Series) Tests Acceptance/production tests shall be performed on each lot of parts (see section 1
112、9, note 3 and 4 for definition of lot). Unless specified otherwise, the following are required acceptance/production tests for each of these processes (note that part or parts selected for examination shall be after all thermal processes have been completed): Through-Hardening : Surface hardness; co
113、re hardness; surface microstructure. Gas Carburizing :Case hardness; surface and case microstructure; case depth. Gas Nitriding :Case hardness; case microstructure; case depth. Carbonitriding : Case hardness; surface and case microstructure; case depth. Gaseous Nitrocarburizing : Depth of compound l
114、ayer; presence of compound layer; compound layer hardness. Salt Bath Nitrocarburizing : Depth of compound layer; presence of compound layer; compound layer hardness. Induction Hardening: Surface hardness; depth of hardened layer; microstructure of hardened layer; induction hardened pattern. Periodic
115、 Tests Periodic tests shall be performed at a frequency selected by the heat-treater (as per control plan) unless frequency of testing is specified otherwise by the engineering print. Unless specified otherwise, the following are required periodic tests for each of these processes (Note that part or
116、 parts selected for examination shall be after all thermal processes have been completed): Through-Hardening : Core microstructure. Gas Carburizing : Core hardness; core microstructure. Gas Nitriding : Core hardness; thickness of compound zone. Carbonitriding : Core hardness; core microstructure. Ga
117、seous Nitrocarburizing : Compound layer microstructure; diffusion zone hardness; diffusion zone depth. Salt Bath Nitrocarburizing : Compound layer microstructure; diffusion zone hardness; diffusion zone depth. Induction Hardening: Core hardness; core microstructure. GLOBAL STANDARDGlobal Heat-Treat
118、Standard GS-0062.A Page 17 of 22 17 TEST REPORT REQUIREMENTS Reports shall show the results of tests made on parts to determine conformance to acceptance/production, periodic, or preproduction tests as applicable. Reports shall include the purchase order number, shop order number, part number, furna
119、ce(s) used, load number(s), thermal processing temperatures, times, and cooling cycles used, temperature and method of straightening, dates, and quantity of parts heat treated. 18 GENERAL OPERATING SYSTEM REQUIREMENTS The heat-treat must establish and maintain a documented operating system according
120、 to ISO 9001. This requirement applies to the quality system, the process and the maintaining of the heat-treat equipment. 18.1 Quality System The heat-treat shop shall establish and maintain a documented quality system as a means of ensuring that the products conform to requirements. Specifically,
121、the shop must have documented procedure(s) for: a)Receiving inspection b)Process inspection c)Final inspection d)Nonconformity review and Disposition e)Corrective actions f)Process Control (Control Plans and FMEAs) 18.2 Contract Review The supplier/customer shall establish and maintain procedures fo
122、r contract review and for the coordination of these activities. a)Clear drawings: The heat-treater must review the drawing and ensure that it provides clear information on: hardness, case depth, place of measurement, measurement parameters, measurement load, material, masking, etc. This review inclu
123、des ensuring the material specified will consistently meet the final specifications after the heat-treat process. If this information is not clear, the heat-treater must request this information from engineering. b)Clear heat-treat orders c)Documentation of heat-treat orders d)Good description of pa
124、rts 18.3 Process Control The heat-treat shop shall identify and plan the production, which directly effect quality, and shall ensure that these processes are carried out under controlled conditions a)The recording of processes b)The following of safety regulations c)The documenting of processes and
125、process steps: As per Sauer-Danfoss PPAP requirement, the process parameters of the heat-treat process must be defined and a significant production run performed and tested to ensure compliance to the material specifications. Significant deviations from these process parameters are not allowed witho
126、ut signed deviation from the customers engineering function. GLOBAL STANDARDGlobal Heat-Treat Standard GS-0062.A Page 18 of 22 18.4 Maintenance of the Heat-Treat EquipmentThe heat-treat shop shall establish and maintain a documented maintenance system as a means of ensuring that the technical equipm
127、ent can consistently meet requirements. a)Maintenance plans for the heat-treat equipment b) Maintenance plans for the gas, energy and water supplyc) Maintenance plans for the control equipmentd) The documentation of maintenance actions19 APPENDIX A: General Notes 1. Copper ammonium chloride solution
128、: Dissolve 100 grams cupric chloride (CuCl2.2H2O) in distilled water to make one liter. Add ammonium hydroxide to form a copper ammonium chloride complex. 2. Copper sulfate solution: Dissolve 40 grams of copper sulfate (CuSO4.5H2O) in 1000 ml of distilled water and 5 ml wetting agent (e.g. glycerine
129、); pH shall be 3.5 to 4.1. 3. A lot (other then for induction hardening see note 4 below) shall be all parts of the same part number processed in the same furnace load. See also section 4.3.2 of AMS 2759 (see Table 4.1 for DIN equivalent): a lot shall be all parts of the same design, fabricated from
130、 the same alloy, heat treated to the same property requirements in the same furnace(s) at the same time, and presented for processors inspection at the same time. In addition, for a continuous furnace, it shall be those parts heat treated as a continuous production run during an eight-hour shift. Wh
131、en testing parts after operations (e.g. stress relieving, baking, hot or warm straightening) that occur after the final step of the heat operation (e.g. tempering, aging), a lot, in addition to the above, shall consist of parts stress relieved, baked, hot or warm straightened, etc using the same equ
132、ipment at the same time. 4. A lot for induction hardened parts shall be defined as all parts of the same part number, material, and condition processed together or sequentially within an 8 hour period, using the same equipment under identical control settings for heating and cooling, including the t
133、iming thereof. 5. Heat Affected Zone (HAZ): The heat affected zone is the depth below the hardened surface which last exhibits microstructural evidence of having exceeded the lower critical temperature (Ac1) and/or that portion of the base metal within which microstructural and physical properties w
134、ere altered by the treatment. GLOBAL STANDARDGlobal Heat-Treat Standard GS-0062.A Page 19 of 22 20APPENDIX B: Thickness Limits for Surface Hardness Measurements of Surface Treated Materials Thickness limits for surface hardness measurement of surface treated materials as a function of hardness metho
135、d and test load are shown in Tables 1 and 2. The source for these tables is DIN 6773. A similar presentation of thickness limits is provided in ASTM E18 (not shown). ASTM E18 also provides correction factors for convex cylindrical surfaces. Table 1 Thickness Limits for Surface Hardness Measurement U
136、sing Vickers (Basis is DIN 6773) Min. Case Depth, Rht,Eht, Nht, (mm)* 200-300 (HV) 300-400 (HV) 400-500 (HV)500-600 (HV) 600-700 (HV)700-800 (HV) 800 (HV)0,05 - - - HV 0,5HV 0,5HV 0,5HV 0,50,07 - HV 0,5 HV 0,5HV 0,5HV 0,5HV 1 HV 10,08 HV 0,5HV 0,5HV 0,5HV 0,5HV 1HV 1HV 10,09 HV 0,5HV 0,5HV 0,5HV 1HV
137、 1HV 1HV 10,1 HV 0,5HV 1HV 1HV 1HV 1HV 1HV 30,15 HV 1HV 1HV 3HV 3HV 3HV 3HV 50,2 HV 1HV 3HV 5HV 5HV 5HV 5HV 50,25 HV 3HV 5HV 5HV 5HV 10HV 10HV 100,3 HV 3HV 5HV 10HV 10HV 10HV 10HV 100,4 HV 5HV 10HV 10HV 10HV 10HV 30HV 300,45 HV 5HV 10HV 10HV 10HV 30HV 30HV 300,5 HV 10HV 10HV 10HV 30HV 30HV 30HV 300,
138、55 HV 10HV 10HV 30HV 30HV 30HV 50HV 500,6 HV 10HV 10HV 30HV 30HV 50HV 50HV 500,65 HV 10HV 30HV 30HV 50HV 50HV 50HV 500,7 HV 10HV 30HV 50HV 50HV 50HV 50HV 500,75 HV 30HV 30HV 50HV 50HV 50HV 100HV 1000,8 HV 30HV 30HV 50HV 50HV 100HV 100HV 1000,9 HV 30HV 30HV 50HV 100HV 100HV 100HV 1001,0 HV 30HV 50HV
139、100HV 100HV 100HV 100HV 100Minimum Surface Hardness and Vickers Test Load GLOBAL STANDARDGlobal Heat-Treat Standard GS-0062.A Page 20 of 22 Table 2 Thickness Limits for Surface Hardness Measurement Using Rockwell and Rockwell Superficial (Basis is DIN 6773) Min. Case Depth, Rht, Eht, (mm)*) 82-85 (H
140、R 15N) 85-88 (HR15N) 88 (HR15N)60-68 (HR30N) 68-73 (HR30N)73-78 (HR30N) 78 (HR30N)44-54 (HR45N 54-61 (HR45N 61-67 (HR45N 67 (HR45N) 0,1 - - HR15N- - - - - - - - 0,15 - HR15NHR15N- - - - - - - - 0,2 HR15N HR15NHR15N- - - HR30N- - - - 0,25 HR15NHR15NHR15N- - HR30NHR30N- - - - 0,35 HR15NHR15NHR15N- HR3
141、0NHR30NHR30N- - - HR45N0,4 HR15NHR15NHR15NHR30NHR30NHR30NHR30N- - HR45NHR45N0,5 HR15NHR15NHR15NHR30NHR30NHR30NHR30N- HR45NHR45NHR45N0,55 HR15NHR15NHR15NHR30NHR30NHR30NHR30NHR45NHR45NHR45NHR45NMin. Case Depth, Rht, Eht, (mm)*) 70-75 (HR A) 75-78 (HRA) 78-81 (HRA)81 (HRA) 40-49 (HRC)49-55 (HRC) 55-60
142、(HRc)60 (HRC) 0,4 - - - HRA- - - - 0,45 - - HRAHRA- - - - 0,5 - HRAHRAHRA- - - - 0,6 HRAHRAHRAHRA- - - - 0,8 HRAHRAHRAHRA- - - HRC0,9 HRAHRAHRAHRA- - HRCHRC1,0 HRAHRAHRAHRA- HRCHRCHRC1,2 HRAHRAHRAHRAHRC HRCHRCHRC*) Rht = Case depth for inductive and flame hardening Eht = Case depth for carburizing a
143、nd carbonitriding Nht = Case Depth for nitriding and nitrocarburizing Minimum Surface Hardness for Rockwell and Rockwell Superficial Test Loads GLOBAL STANDARDGlobal Heat-Treat Standard GS-0062.A Page 21 of 22 21 APPENDIX C: Case Depth Determination According to DIN 50190 1. Diagram of hardness vers
144、us distance from the surface 3 X d3 X d2,5 X dLH = Limiting hardness* or effective case depth) CH = Core hardness CD = Case depth (Carburizing, Nitriding and Induction Hardening) *) The limiting hardness is determined as followed: a) Carburizing and carbonitriding: 550HV1 or 52.5 Rc (unless designat
145、ed otherwise) b) Nitriding and nitrocarburizing: Core hardness + 50HV0.5 c) Induction hardening: 80% of the required minimum surface hardness using HV1 (unless designated otherwise) 2. Making an acceptable sample The hardness layer to be examined must be positioned at a right angle to the surface of
146、 the sample unless an oblique section method is being used. The sample should be ground and polished to a surface flatness of 1m. 3. Setting the impressions The gap between the center of the impressions shall be a minimum of 3.0 times the diameter of the impression and no closer to the edge of the s
147、ample than 2.5 times the diameter. The impressions have to be sufficiently distributed so that the curve of case depth can be easily determined. 4. Result of the investigation The point of intersection between the hardness curve and the limiting hardness (LH) is defined as the effective case depth.
148、Distance fromHCHLHCDtheborder (mm)ardness(H0,5/1)GLOBAL STANDARDGlobal Heat-Treat Standard GS-0062.A Page 22 of 22 22 APPENDIX D: Martensite/Austenite Rating Chart The rating chart shown below provides a visual estimation of per cent Retained Austenite. A microstructure sample is to be prepared by polishing, etching in 3.5% Nital, and viewed at 400X. Note that this is a rough visual estimation and a requirement for more precise measured amounts of Retained Austenite should be determined by x-ray diffraction. CHANGE HISTORY:
