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核电设备制造中的异种金属接头在焊接、焊后热处理和使用过程中,可能发生碳元素沿着焊缝熔合线由珠光体钢向奥氏体堆焊层或焊缝的定向扩散的情况,造成熔合线两侧性能不均匀,导致规定的功能丧失。文章选取了4个核岛关键设备典型焊接工艺评定作为实例,重点对不合格试样进行了分析研究,对异种金属焊接碳迁移问题作了一些探讨。 相似文献
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在石油化工管道施工中,常遇到奥氏体不锈钢与珠光体耐热钢的焊接。由于这两种钢材的物理——化学性能各不相同,差异很大,焊接时,焊缝的稀释、熔合区形成的过渡层和扩散层,以及接头的应力状态都对可焊性有重大影响,因而有一定的焊接难度。所以焊接异种钢接头,为保证工程质量有必要进行分析和试验,制定严格的合适的焊接工艺,才能得到可靠的焊接接头质量。 一、15CrMo与0Cr18Ni9Ti钢可焊性分析 相似文献
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针对SAFUREX双相不锈钢与A106B理化性能,分析该异种钢的焊接性.实际应用表明,选取合适的焊接材料和焊接工艺参数,能够获得性能优良的焊接接头. 相似文献
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换热器广泛应用于石油、化工等领域,其使用环境较为恶劣,导致腐蚀失效现象较为严重。大量统计结果表明多数换热器失效都发生在换热管与管板焊接接头处,因此,提升接头处焊缝耐蚀性能成为解决其失效问题的关键。采用金相显微镜和扫描电镜,分析了焊接电流对换热器管-板接头焊缝晶粒尺寸及组织类型的影响;采用电化学实验方法,分析了微观组织对焊接接头腐蚀产物膜及耐蚀性的影响。结果表明:焊接电流120A时接头焊缝晶粒最小、组织最均匀,焊接电流的增加导致了热输入量的增加进而促进了焊缝基体中晶粒的长大;晶粒尺寸及组织不均匀性与焊缝的耐蚀性呈负相关关系;三种焊接电流下焊缝腐蚀产物膜主要由α-FeOOH和γ-FeOOH组成,焊接电流120A时焊缝腐蚀产物膜致密性最好,表现出最好的耐蚀性,160A时致密性最差,表现出最差的耐蚀性。研究了焊接电流对管-板焊缝耐蚀性的影响,对换热器制造具有一定的参考意义。 相似文献
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Electrical resistance tomography (ERT) as a non‐invasive technique based on conductivity measurement of the continuous phase was employed for the study of phase holdup in a liquid‐solid circulating fluidized bed (LSCFB). Local solid holdup was also measured by an optical fibre probe and pressure transducers to compare and verify the results obtained by ERT. Good agreement was observed among the three methods. Tap water was used as the continuous and conductive phase and glass beads (spherical shape) and lava rocks (irregular shape) of two different sizes were used as the solid and non‐conductive phase. Radial non‐uniformities of solid holdups were observed for all four types of particles under different superficial liquid velocities in different axial locations. The solid holdup was higher in regions close to the wall and low in the central region. Non‐uniformity in the phase holdup decreased with increasing liquid velocity. The axial flow profile was found uniform along axial locations of the riser except at the lower location closer to the distributor zone. 相似文献