制氢装置用347H承压管道焊后热处理标准浅析

Simple discussion on standards about post-weld heat treatment of 347H pressure pipe for hydrogen production unit

介绍了347H不锈钢焊后热处理分类,分析了奥氏体不锈钢焊后热处理国内外标准现状。目前国内外标准对347H不锈钢管道焊后热处理的规定不一致,NB/T 10068—2018提出以操作温度和厚度范围作为347H不锈钢焊后热处理实施条件,为制氢装置用347H承压管道是否进行焊后热处理提供了指引,具有一定的参考意义。但该标准部分条款尚不完善,在铁素体测量顺序、铁素体含量合格值和铁素体测量方法方面还存在一定的问题,建议应将焊缝铁素体含量测量调整至焊后热处理前,取消固溶+稳定化热处理后的铁素体数为3 FN的下限值,增加E(R)16.8.2型熔覆金属铁素体含量合格值要求,同时明确铁素体含量检测方法。该标准关于焊后稳定化热处理实施条件的规定尚不完善,建议应结合工程实践经验和国外先进标准,设置焊后热处理豁免条件,对于操作温度≥500℃的薄壁和焊接接头拘束度较小工件,豁免其焊后热处理,以维持标准的科学性和先进性。NB/T 10068—2018未充分做好专利信息披露工作,后续应做好专利信息披露,防止出现知识产权劫持标准的状况。

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.