GB/T 37558-2019 English PDFUS$519.00 · In stock
Delivery: <= 5 days. True-PDF full-copy in English will be manually translated and delivered via email. GB/T 37558-2019: Preliminary heat treatment of heavy steel forgings Status: Valid
Basic dataStandard ID: GB/T 37558-2019 (GB/T37558-2019)Description (Translated English): Preliminary heat treatment of heavy steel forgings Sector / Industry: National Standard (Recommended) Classification of Chinese Standard: J36 Classification of International Standard: 25.200 Word Count Estimation: 26,230 Date of Issue: 2019-06-04 Date of Implementation: 2020-01-01 Issuing agency(ies): State Administration for Market Regulation, China National Standardization Administration GB/T 37558-2019: Preliminary heat treatment of heavy steel forgings---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.Preliminary heat treatment of heavy steel forgings ICS 25.200 J36 National Standards of People's Republic of China Post forging heat treatment of large forgings Published on.2019-06-04 2020-01-01 implementation State market supervision and administration China National Standardization Administration issued ContentForeword III 1 Scope 1 2 Normative references 1 3 Terms and Definitions 1 4 Forged steel parts to be processed 2 5 Forging heat treatment equipment 2 6 Forging heat treatment process 3 7 Quality and inspection of post-forging heat treatment 5 8 school shape 6 9 Safety and health requirements 6 10 Energy consumption requirements 6 11 Product Quality Report Form 6 Appendix A (informative) Normalized fire (or annealing) and high temperature tempering temperature of each steel grade 8 Appendix B (informative appendix) White spot annealing process after forging 13 Appendix C (informative) Hydrogen diffusion calculation method for dehydrogenation annealing process 14 Appendix D (informative) Calculation method for effective thickness of forged steel parts 18 Appendix E (informative) Grain grain refining normalizing process after forging 20ForewordThis standard was drafted in accordance with the rules given in GB/T 1.1-2009. Please note that some of the contents of this document may involve patents. The issuing organization of this document is not responsible for identifying these patents. This standard is proposed and managed by the National Heat Treatment Standardization Technical Committee (SAC/TC75). This standard was drafted. Shanghai Jiaotong University, Shanghai Electric Heavy Forging Co., Ltd., Shanghai Materials Research Institute, Beijing Electromechanical Research Company, Shanghai Rail Transit Inspection Technology Co., Ltd., Hubei Sanhuan Forging Co., Ltd., Guizhou Aerospace Technology Development Co., Ltd. Luoyang Zhongzhong Casting & Forging Co., Ltd., Xi'an Follett Heat Treatment Co., Ltd., Jiangsu Fengdong Heat Treatment and Surface Modification Engineering Technology Research Co., Ltd. The main drafters of this standard. Han Lizhan, Xu Yueming, Gu Jianfeng, Wang Xiaofang, Ren Yizan, Lei Xue, Cai Hong, Dai Heping, Xie Chuangye, Shi Ruxing, Wu Jinchao, Shi Yousen. Post forging heat treatment of large forgings1 ScopeThis standard specifies the technical requirements and methods for heat treatment of large forged steel parts after forging, including the treatment of forged steel parts, post-forging heat treatment Requirements for preparation, post-forging heat treatment, post-forging heat treatment quality and inspection, calibration, safety, hygiene, energy consumption and product quality report. This standard is applicable to the direct heat treatment of large forged steel parts for heavy equipment used in energy, metallurgy, transportation and other industries, such as pre-heating. Anti-white point annealing, grain refining treatment and stress relief annealing.2 Normative referencesThe following documents are indispensable for the application of this document. For dated references, only dated versions apply to this article. Pieces. For undated references, the latest edition (including all amendments) applies to this document. GB/T 231.1 Brinell hardness test for metallic materials - Part 1. Test methods GB/T 6394 method for determination of average grain size of metals GB/T 7232 metal heat treatment process terminology GB/T 9452 heat treatment furnace effective heating zone determination method GB/T 13298 metal microstructure inspection method GB/T 13324 heat treatment equipment terminology GB 15735 Metal heat treatment production process safety and hygiene requirements GB/T 17358 heat treatment production power consumption calculation and determination method GB/T 17394.1 Test of hardness of steel materials - Part 1 . Test methods GB/T 19944 Heat treatment production fuel consumption calculation and determination method GB/T 30824 gas heat treatment furnace temperature uniformity test method GB/T 30825 heat treatment temperature measurement GB/T 32541 heat treatment quality control system Normalizing and annealing of GB/T 37559 large forgings JB/T 5000.15 General technical requirements for heavy machinery - Part 15. Non-destructive testing of forged steel3 Terms and definitionsThe following terms and definitions as defined in GB/T 7232 and GB/T 13324 apply to this document. 3.1 Post-forging heat treatment To eliminate the forging stress, prevent the generation of white spots, refine the grains and uniform structure, and ensure the final heat treatment and/or cutting of the forgings. Performance, meeting ultrasonic testing requirements, pre-heat treatment. Also referred to as a preliminary heat treatment or a first heat treatment. 3.2 Tissue genetic microstructureheredity For the non-equilibrium structure whose original structure is martensite or bainite, under the certain heating conditions, the new austenite grain inheritance and Restore the coarse grain morphology of the original austenite.4 Forged steel parts to be processed4.1 Forging steel data The original data of the forged steel parts shall be delivered to the heat treatment workshop together with the physical materials. The original materials include but are not limited to the contents of Table 1. Table 1 Information on forged steel parts to be processed 4.2 Forged steel parts appearance There shall be no defects such as cracks affecting the quality of the heat treatment on the surface of the forged steel to be treated. 4.3 Acceptance requirements for post-forging heat treatment Before heat treatment, the acceptance requirements for heat treatment of forged steel parts shall be clarified. If there is a sampling test requirement after heat treatment, the sampling position should be determined and taken. Sample method, number of samples and detection method.5 Forging heat treatment equipment5.1 Heating equipment 5.1.1 For the heating of large forgings, the heat treatment furnace should be selected according to the requirements. The heating medium is generally air, and the forgings with special requirements are optional. Use a specific atmosphere furnace. The heat treatment furnace shall be used within the valid period of inspection of its effective heating zone. 5.1.2 The effective heating zone of the heat treatment furnace should be tested every 6 months. The test method should conform to GB/T 9452, GB/T 30824 and GB/T 30825 requires that the test cycle can be extended to one year after passing three consecutive cycles. 5.1.3 The temperature deviation of the effective heating zone of the heating furnace after forging shall comply with the requirements of Table 2, and the other quality requirements shall meet the requirements of GB/T 32541. Relevant regulations. Table 2 Temperature deviation requirements for effective heating zone of post-forging heat treatment furnace Process normalizing annealing tempering Maximum deviation ±15°C ±20°C ±10°C 5.2 Temperature measurement and control equipment 5.2.1 Instrument 5.2.1.1 The type and technical requirements of the heat treatment furnace instrument system shall not be lower than the Class D requirements of GB/T 30825. 5.2.1.2 The instrument system shall perform the accuracy verification regularly before the first use, and the equipment that fails the system accuracy check according to the regulations shall not be used. The instrument system type and system accuracy requirements and calibration period shall meet the requirements of Class IV equipment in GB/T 32541, as shown in Table 3. Table 3 Meter accuracy requirements and calibration period Temperature control instrument accuracy level record meter accuracy level detection cycle 0.5 level 0.5 level 6 months 5.2.2 Temperature sensor 5.2.2.1 The selection and use of temperature sensors shall comply with the provisions of GB/T 30825. 5.2.2.2 Load thermocouples used to measure forging temperatures shall be in intimate contact with the forgings. Load thermocouples should be protected, Not affected by furnace temperature radiation and furnace atmosphere. 5.3 Cooling equipment The normalizing of large forged steel parts is generally cooled in still air, and simple air blowing equipment such as fans and sprays can also be used. The blasting equipment shall ensure that the forged steel parts are placed in the strong flowing air, and the forgings are uniformly cooled as much as possible. Wind speed and air volume can meet the cooling rate required by the process.6 Afterging heat treatment process6.1 Classification Post-forging heat treatment of large forgings includes prevention of white point annealing, stress relief annealing, grain refinement and homogenization treatment. 6.2 Prevention of white point annealing 6.2.1 When the hydrogen content in the forging exceeds the white point limit, the white point annealing should be performed immediately. 6.2.2 The furnace temperature should be controlled to prevent white spots and cracking. 6.2.3 Preventing white point annealing temperature is usually about 650 °C. For specific steel grades, please refer to Appendix A. 6.2.4 Annealing time shall be determined according to the hydrogen diffusion of the forging according to the size of the forging and the original hydrogen content. Appendix B is to prevent white spots A common process for annealing. Refer to Appendix C for the hydrogen diffusion calculation method. 6.2.5 The cooling rate should be slow enough to prevent whitening of excessive transient stress and to minimize residual stress in the forging. Usually will The cooling process is divided into two phases. above 400 ° C, the cooling rate should be less than 60 ° C/h; below 400 ° C, a slower cooling rate should be adopted. 6.2.6 This process can also be carried out simultaneously with the high temperature tempering after normalizing. 6.2.7 For forgings with high hydrogen content, the cycle heating and rapid final cooling process near the Ac1 point of steel can be used to shorten the annealing time. 6.3 Stress relief annealing In order to reduce the stress after heat treatment and reduce the hardness of forgings, annealing treatment should be carried out, which can be carried out according to the relevant provisions of GB/T 37559. 6.4 Grain refinement and homogenization treatment 6.4.1 Normalizing and high temperature tempering 6.4.1.1 For the heat treatment of homogenization and grain refining directly after forging forging, high temperature normalizing is adopted, that is, the heating temperature is Ac1/Ac3 (100 ° C ~ 150 ° C). Refer to Appendix A for the normalizing temperature selected for the specific steel grade. 6.4.1.2 Each temperature zone should be heated at different speeds and have different holding and soaking times. See Table 4 for specific requirements. Important product The thermocouple should be placed in the thickest section of the forging during production, and the temperature equalization process ends when the thermocouple temperature reaches the normalizing temperature. When the surface of the forging is placed more When a thermocouple is used, the soaking process should end when all thermocouple temperatures reach the normalizing temperature. Table 4 Grain Refinement Normalizing Heating Specification a is the effective thickness, see Appendix D for the calculation method. 6.4.1.3 Large forgings shall be controlled for the final cooling temperature during normalizing cooling. The final cooling temperature should be as low as possible to ensure austenite during the cooling process Fully converted; but when the final cold temperature is too low, the forged steel parts are prone to cracking and white spots. 6.4.1.4 High temperature tempering should be carried out in time after normalizing. Refer to Appendix A for high temperature tempering temperature. 6.4.1.5 For grain refining normalizing process after forging, refer to Appendix E. 6.4.2 Multiple normalizing and high temperature tempering 6.4.2.1 When it is difficult to achieve the grain requirement in one normalizing, multiple normalizing and then high temperature tempering may be used. 6.4.2.2 The subsequent normalizing temperature should be lower than the first normalizing temperature. Refer to Appendix A for the last normalizing temperature. The number of normal fires according to the material And forging size settings. 6.4.2.3 After high temperature tempering, high temperature tempering should still be carried out. For high temperature tempering temperature, please refer to Appendix A. 6.4.3 Isothermal annealing 6.4.3.1 For high-hardenability steels with high content of elements such as Cr and Ni, due to the significant genetic inheritance, it can also be cut by isothermal annealing. Tissue inheritance. 6.4.3.2 Isothermal annealing temperature can be referred to Appendix A. The isothermal temperature should be set to the shortest temperature during the pearlite transformation, and the isothermal time is based on The final time of pearlite transformation in the supercooled austenite isothermal transformation kinetic curve was determined. 6.5 Process Control 6.5.1 Operator qualification Heat treatment operators should be trained and have relevant certificates. 6.5.2 Operational requirements 6.5.2.1 Pre-installation inspection The surface of the forging is inspected and cleaned prior to heat treatment to ensure that there are no surface defects that affect the quality of the heat treatment. 6.5.2.2 Loading furnace Due to the special nature of large forgings, the following operational requirements should be noted when forgings are installed. a) Forgings should be placed in the effective heating zone of the heat treatment furnace when the furnace is installed. If using a gas furnace, avoid nozzles and flames directly. Heat the forged steel. b) Forgings with similar shapes and similar effective thicknesses may be heat treated in the same furnace, but the forgings shall be placed so that the furnace gas is inside and outside The surface flow is smooth, ensuring uniform heating and preventing overheating. c) The cold and hot hoisting of forgings should be designed during furnace installation, and reasonable tooling should be used to prevent excessive deformation of forgings. d) Suitable for lifting equipment when forgings are installed. e) If necessary, the furnace should be equipped with reasonable tooling to raise and level the forged steel parts to ensure air circulation in the upper, lower and surrounding parts of the forged steel parts. 6.5.2.3 Lifting Lifting equipment and tooling for forgings shall ensure operational safety. Before production, test suspension is required to ensure safety during operation. Forgings Hanging equipment and tooling should consider the effect on the cooling effect of the forgings. 6.5.2.4 Cooling After the forging is finished at the specified temperature, it shall be cooled according to the method specified in the process. When the forging is cooled in the air after it is released, it should be forged. The parts are padded and leveled to ensure air circulation around the forgings and up and down. If blasting or spraying is required, the forgings should be evenly cooled. 6.5.3 Recording The production of forgings shall be recorded as follows. a) The production equipment, temperature record, forging position and lifting method used in the production of forgings shall be recorded in detail. b) All records shall be signed and confirmed by the relevant operator at the end of the operation. c) The retention of this record shall ensure traceability of the quality of the forging. 7 Quality and inspection of post-forging heat treatment 7.1 Inspection items and methods 7.1.1 Surface inspection After the forging is finished, the forgings should first be tested for defects such as cracks and scratches. If necessary, magnetic powder or penetrant inspection can be used. The test method is tested in accordance with relevant standards. 7.1.2 Surface hardness If the purchaser has regulations, the surface hardness of the forgings should meet the requirements of the technical documents. The technical document should indicate the location of the surface hardness test and test. Test method and acceptance requirements. The surface hardness test of forgings shall be carried out in accordance with the requirements of GB/T 231.1 or GB/T 17394.1. 7.1.3 Size inspection After heat treatment, the corresponding instruments and gauges should be used to measure the size of the forgings to ensure the final delivery size requirements of the forgings. 7.1.4 Nondestructive testing Forgings requiring non-destructive testing may be carried out in accordance with JB/T 5000.15, if otherwise specified in the contract, as required by the contract. 7.1.5 Metallographic examination Forgings requiring metallographic examination may be subjected to microstructure inspection and grain size evaluation in accordance with GB/T 13298 and GB/T 6394. Combined Except as otherwise specified in the same contract, it shall be implemented as required by the contract. 7.2 Testing equipment and testing personnel 7.2.1 Equipment The measuring equipment used for the quality inspection of forgings after forging heat treatment shall be inspected and calibrated regularly by the metrology department, and a certificate of conformity shall be issued. And when the test is performed, the test equipment should be within the valid calibration period. 7.2.2 Personnel The inspectors shall be trained and assessed according to the regulations, and the inspection work may be carried out after having the corresponding professional qualification certificates. 7.3 Reheat treatment If the grain size does not meet the requirements or the ultrasonic flaw detection sensitivity does not meet the relevant requirements, the forging should be reheated. If the hardness is too high, It is not conducive to the tempering when it is not suitable for cutting.8 school shape8.1 When forgings need to be shaped, they should be calibrated before high temperature tempering. 8.2 After high temperature tempering, the shape shall be corrected. After the forging is shaped, the stress relief annealing shall be performed. The annealing temperature shall be lower than the previous high temperature tempering temperature. Above 20 °C.9 Safety and hygiene requirementsThe safety and hygiene of the large forged steel parts after forging heat treatment shall comply with the provisions of GB 15735. 10 Energy consumption requirements The energy consumption quota for normalizing and annealing processes shall comply with the relevant provisions of GB/T 17358 and GB/T 19944. 11 Product Quality Report Reports can be issued on a per-batch or per-furnace basis as required. The report should include the following. a) furnace number; b) process type or process code; c) the quantity and quality of forgings; d) quality inspection results; e) the basis for testing or judging; f) the name or code of the inspector; g) the name of the processing unit; h) Report date. year, month and day.Appendix A(informative appendix) Normalizing (or annealing) and high temperature tempering temperatures of various steel grades Table A.1 is the reference temperature for normalizing or annealing and high temperature tempering of different steel grades. Ta......Tips & Frequently Asked Questions:Question 1: How long will the true-PDF of GB/T 37558-2019_English be delivered?Answer: Upon your order, we will start to translate GB/T 37558-2019_English as soon as possible, and keep you informed of the progress. The lead time is typically 3 ~ 5 working days. 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