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Published in last 1 year |  In last 2 years |  In last 3 years |  All Please wait a minute... For Selected: Download Citations EndNote Ris BibTeX Toggle Thumbnails Select Simple discussion on standards about post-weld heat treatment of 347H pressure pipe for hydrogen production unit Zhang Yucheng, Jia Haomei Heat Treatment of Metals    2023, 48 (1): 270-276.   doi:10.13251/j.issn.0254-6051.2023.01.048 Abstract （77）      PDF （607KB）（56）       Knowledge map    Classification of post-weld heat treatment of the 347H stainless steel was introduced, and the status quo of domestic and foreign standards of post-weld heat treatment for austenitic stainless steels was analyzed. At present, domestic and foreign standards have different provisions on the post-welding heat treatment of the 347H stainless steel pipes. The NB/T 10068—2018 standard proposes that the operating temperature and thickness range should be used as the implementation conditions of post-weld heat treatment of the 347H stainless steel, which provides guidance for the post-welding heat treatment of the 347H pressurized pipe used in hydrogen production plant and has certain reference significance. But some of the provisions of the standard are not perfect, including some problems in ferrite measurement sequence, ferrite content qualified value and ferrite measurement method. So it is suggested to adjust the measurement of ferritic content of weld to before post-weld heat treatment, remove the lower limit of ferrite number of 3 FN after solution and stabilization heat treatment, add the qualified value requirement of ferrite content of E(R)16.8.2 cladding metal, and define the detection method of ferrite content. At the same time, the NB/T 10068—2018 standard is not perfect on the implementation conditions of post-welding stabilization heat treatment, so it is suggested that the exemption conditions for post-welding heat treatment should be set in combination with engineering practice experience and foreign advanced standards. For thin-walled workpieces with operating temperature ≥500 ℃ and welded joints with small constraint degree, the post-welding heat treatment should be exempted, so as to maintain the scientific and advanced nature of the standard. The NB/T 10068—2018 standard does not fully disclose the related patent information, thus the patent information disclosure should be done well subsequently to prevent intellectual property hijacking of standards. Reference | Related Articles | Metrics Select Interpretation on national standard of GB/T 32151.19—2024 Requirements of the greenhouse gas emissions accounting and reporting —Part 19: Heat treatment enterprise Chen Yi, Zhu Jia, Zhang Tian, Su Miao, Han Yongzhen, Li Zhimei, Jia Yunke Heat Treatment of Metals    2024, 49 (12): 316-318.   doi:10.13251/j.issn.0254-6051.2024.12.051 Abstract （57）      PDF （1252KB）（18）       Knowledge map    According to the characteristics of heat treatment processing and service enterprise, the national standard GB/T 32151.19—2024 Requirements of the greenhouse gas emissions accounting and reporting—Part 19: Heat treatment enterprise puts forward the boundary and reporting scope of greenhouse gas emissions accounting, and clearly stipulates the calculation method of carbon emission of fixed combustion source and process emission and the acquisition method of related emission factors. The release and implementation of the standard provides a basis for enterprises to establish and improve the quality management of carbon emission data. Related Articles | Metrics Select Comparative analysis of domestic and foreign standards for metallographic examination of α+β titanium alloy for surgical implants Li Fan, Gao Na, Zhang Luwen, Guo Linlin, Lou Gui, Zhang Bo Heat Treatment of Metals    2024, 49 (6): 277-281.   doi:10.13251/j.issn.0254-6051.2024.06.043 Abstract （52）      PDF （1594KB）（30）       Knowledge map    Microstructure requirements of titanium alloy in surgical implant standards in domestic and foreign were compared and analyzed. The microstructure of plates in GB/T 13810-2017 requires that the original β grain should be fully broken, and continuous grain boundary α phase is not allowed, the microstructure of bars and wires should conform to figure A.1 (a-i) of the standard. The latest versions of ISO 5832-3, ASTM F136, and ASTM F1472 all specify that the microstructure shall be equiaxial and/or elongated primary α phase distributed on the transformed β matrix, with no continuous α network on the prior β grain boundaries. Among them, the transverse microstructure of the bars in ISO 5832-3 shall correspond to A1-A9 in ISO 20160. Combined with the thermal mechanical processing technology of titanium alloy, when the temperature of hot processing and recrystallization is lower than the β transition temperature, or slowly cooling, high volume fraction of primary α phase and intergranular β will be obtained, recrystallization treatment at close to the β transition temperature will obtain equiaxial primary α phase uniformly distributed on the β matrix, which is represented by A1-A9 in the standard spectrum. After recrystallization above the β phase transition temperature, continuous grain boundary α, network α and lamellar α phases are obtained between the coarse β grains, which are manifested as A10-A24 in the standard diagram. Reference | Related Articles | Metrics