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45Mn17Al3低磁钢质优价廉,但在海水中使用腐蚀严重.通过对45Mn17Al3奥氏体低磁钢试样进行室内腐蚀挂片试验、电化学性能测试、显微腐蚀试验及冶金因素分析,初步探讨了该型钢在海水介质中发生腐蚀的微观机制.室内腐蚀挂片试验和电化学性能测试结果表明,低磁钢的耐蚀性比3C钢要差;显微腐蚀试验结果证明,钢中的夹杂会诱发点蚀;冶金因素分析结果显示,钢中存在大量的AlN夹杂物,而且其微观组织比3C钢的粗大.45Mn17Al3中高的Al含量和大量的AlN夹杂的存在对该型钢耐海水腐蚀性能有重要的影响. 相似文献
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通过极化试验比较了4种含有不同合金元素的低合金钢的点蚀诱发敏感性,并用电子探针对钢中的主要夹杂物及点蚀诱发后的腐蚀形态作了鉴定。结果表明:镍—铬系钢比锰系钢具有更好的耐点蚀性能;点蚀总是从夹杂物与周围钢基体毗邻的界面处开始诱发;含有硫化物的复相夹杂对点蚀的敏感性更强。 相似文献
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硫系易切削钢中主要依靠硫化物夹杂来改善切削性能,分布均匀的球状硫化物最有利于切削加工,且对钢材力学性能的损害也是最小的。本文研究了氧含量以及脱氧方式对30MnVS铸态组织中硫化物形貌的影响。结果显示,舢脱氧样品中,由于Al含量较高硫化物都是以沿晶界分布的杆状硫化物为主,主要以共晶反应的形式在凝固的最后阶段形成。采用Mn—Si脱氧,降低样品中Al含量,凝固时形成的硫化物主要以球状或液滴状为主,且绝大部分硫化物中含复合氧化物核心。 相似文献
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采用化学浸泡法和模拟闭塞电池方法研究了固溶+时效和固溶+调整+时效处理的0Cr17Ni4Cu4Nb马氏体不锈钢的耐点腐蚀性能,并与18-8型奥氏体不锈钢(316L)耐点蚀性能进行了对比。结果表明,0Cr17Ni4Cu4Nb马氏体不锈钢组织内富Cu析出相促进了点蚀坑萌生,而点蚀坑发展则与组织形貌有关。固溶+调整+时效处理的0Cr17Ni4Cu4Nb马氏体不锈钢因组织内析出富Cu相多而大,其萌生的点蚀坑密度较高,但由于马氏体板条较细,其点蚀坑尺寸和深度较小;固溶+时效处理的0Cr17Ni4Cu4Nb马氏体不锈钢因组织内析出富Cu相少而小,萌生的点蚀坑密度较低,但粗大的板条马氏体组织导致点蚀坑尺寸和深度较大。与18-8型奥氏体不锈钢耐点蚀性能对比表明,通过对0Cr17Ni4Cu4Nb马氏体不锈钢进行合理的热处理,其耐点蚀性能可与18-8型奥氏体不锈钢相当。 相似文献
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采用间浸腐蚀试验、极化曲线测试、扫描观察(SEM)和透射电镜观察(TEM)等方法研究了在3.5%NaCl溶液中添加氧化剂以及敏化处理对低温高锰钢局部腐蚀性能的影响。结果表明:经间浸腐蚀试验后,各试样均主要发生全面非均匀腐蚀,局部可见点腐蚀特征。试样在3.5%NaCl溶液中腐蚀产生的锈层疏松,在3.5%NaCl+0.25%Na2S2O8溶液中腐蚀,试验初期自腐蚀电流密度提高两个数量级,在较短时间内产生致密的锈层,阻止了试验后期腐蚀向内层的快速扩展,试样平均腐蚀速率降低,点腐蚀深度减小。800 ℃×5 h敏化处理后,高锰钢的组织结构没有发生改变,晶界析出了断续分布的碳化物,其抗腐蚀性能与原始态相当,极化曲线印证了这一结果。 相似文献
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采用化学浸泡腐蚀试验及微观组织和化学成分分析研究了5种铸造双相不锈钢在6%Fe Cl3溶液中的点腐蚀行为,并与316L奥氏体不锈钢进行了对比。结果表明,铸造双相不锈钢的抗点腐蚀性能均优于316L的,腐蚀速率和点腐蚀深度均小于316L奥氏体不锈钢的;双相不锈钢主要耐点蚀能力合金元素在奥氏体和铁素体相内分布不均匀,铬、钼更多地分配于铁素体相内,而镍、氮则更多地分配于奥氏体相内,铁素体相的耐点蚀指数PRE(Cr%+3.3Mo%+16N%)大于奥氏体相;双相不锈钢的耐点腐蚀性能与化学成分有关,随着PRE的增加,双相不锈钢的耐点腐蚀性能提高,铜元素在铁素体内析出的富铜相导致点蚀优先在铁素体内发生和发展。 相似文献
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Stainless steels usually contain some amounts of sulfide type of inclusions which are known to affect their corrosion behavior in mild aqueous chloride solutions. The life of the stainless steel components is severely affected as the manganese sulfide inclusions dissolve and the reaction products at the site of inclusions lead to pitting corrosion. The pits so formed as well as manganese sulfide inclusions, being local heterogeneities were studied by a microprobing technique called scanning electrochemical microscopy. In order to demonstrate how this local probing technique can be optimally used to investigate the corrosion behavior of inclusion containing austenitic stainless steels, different experimental parameters were varied one by one. The effect of different factors such as substrate potential, rate of scanning and concentration of chloride was studied in detail. The study shows that a scan rate of 0.32 μm/s (3.2 μm step distance for 10 s hold time) for 50 μm by 50 μm scans and a scan rate of 0.1 μm/s (1 μm step distance for 10 s hold time) for 20 μm by 20 μm scans produced optimum results throughout the study. 相似文献
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为提高AH36钢的耐海水腐蚀性能,炼钢时引入了钢水钙处理工艺.本文通过室内间浸挂片试验、交流阻抗试验、动电位极化试验及极化试验后的SEM分析,研究了钙处理对AH36钢中的夹杂物及耐点蚀性能的影响.结果表明:变性夹杂物中的CaS对钙处理钢的耐点蚀性能有明显的影响.通过钙处理把钢中氧化铝夹杂、硅铝酸盐夹杂等球化变性成无CaS或低CaS的球状CaO-Al2O3复合夹杂,可有效提高钢的耐点蚀性能;变性球状复合夹杂中含较多的CaS会促进诱发夹杂物周围基体腐蚀,提高点蚀诱发敏感性;含硫量较高的AH36钢在钙处理不充分时,形成CaS夹杂或以CaS为主的复合夹杂,会使AH36钢的耐点蚀性能恶化. 相似文献
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P. Saravanan Y. Govindaraj B. Khalkho S. Srikanth V. Kumar L. Neelakantan 《Materialwissenschaft und Werkstofftechnik》2023,54(5):615-626
Influence of composition, specifically manganese and nitrogen content, on the microstructure associated corrosion resistance property of newly developed stainless steel has been studied. The developed steels have been characterised for their microstructure, mechanical and electrochemical properties. The results indicate that the addition of manganese and nitrogen as a substitute for nickel favours the austenite microstructure, higher yield strength (>350 MPa), tensile strength (>700 MPa), elongation and superior Charpy V-notch impact toughness properties. The results obtained from electrochemical tests such as potentiodynamic polarisation and electrochemical impedance spectroscopy of manganese stainless steel show remarkable improvement (about 4 times) in corrosion resistance exhibiting passivity behaviour like that of commercial stainless steel (316L). 相似文献
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《Scripta Metallurgica》1984,18(5):499-504
The results of this study indicate certain trends in the response of a low-carbon cast steel to deformation in a hydrogen environment. For a heat of given nominal composition, castings can vary substantially in composition and structure, and the effects of some of those variations were indicated. As would be expected, metalloid impurities proved to be detrimental to ductility; this behavior was largely due to the presence of Type II manganese sulfide inclusions. In other castings with the manganese sulfide inclusions in another form, such as Type I (more uniform distribution), the effect of metalloids could be similar but may not be so pronounced as found here; this can be inferred by comparing the clean and doped steels after hot rolling, which redistributed the manganese sulfide inclusions.For the clean steel, in which the sulfide inclusions did not control the fracture process, annealing and hot rolling reduced the tendency for lower ductility fracture modes to be promoted by hydrogen, presumably by refining the microstructure and/or redistributing segregated impurities more uniformly. The observed fracture-mode transitions suggest that hydrogen may reduce the fracture toughness of the as-cast clean steel, by reducing local plastic deformation, to a much greater extent than that of the wrought steel. 相似文献
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针对某段时期出现的X52管线钢产品经抗阶梯型破裂试验后,试样有明显阶梯裂纹,产品检验不合格的问题,对不合格批次的试样进行化学成分、炼钢工艺以及显微组织等方面的分析,分析了该抗硫化氢腐蚀X52管线钢氢致开裂的原因。结果表明:开裂批次试样的钙硫含量比值偏低,导致出现夹杂物偏聚和中心偏析,且夹杂物呈线状分布,是造成该管线钢产品抗氢致开裂试验开裂的主要原因。最后对X52管线钢的生产控制要点提出了相应建议,以提高其抗硫化氢腐蚀的能力。 相似文献