Corrosion Resistance of Reactive Element Aluminide Diffusion Coatings on a Nickel‐based Superalloy and an Austenitic Stainless Steel

Continuously cast aluminium alloy wires containing active elements such as yttrium, cerium, lanthanum or silicon were used as evaporation sources for ion vapour deposition on nickel‐based Inconel IN738 and stainless steel 310S substrate materials. The samples were subsequently diffusion heat‐treated to form protective corrosion resistant nickel aluminide and iron aluminide coatings. The coated alloy materials were exposed for prolonged periods to high temperature cyclic oxidation, molten sulphate, and molten carbonate environments to evaluate their resistance to hot oxidation. For IN738, the lanthanum‐modified aluminide coating provided good thermal cyclic oxidation performance while the cerium‐modified coating exhibited effective hot corrosion resistance in a molten sulphate environment. For 310S stainless steel, all of the modified aluminide coatings provided equally good corrosion protection when exposed to molten carbonate attack under an oxidizing atmosphere.     

不锈钢在高温高压釜乙酸溶液中耐腐蚀性能研究

在试验室中模拟不锈钢所处的高温高压生产环境,对两种牌号不锈钢在同种乙酸介质中的耐腐蚀性能进行对比实验研究,并且对同种不锈钢试样在不同方法制备的乙酸介质中的耐腐蚀性能进行对比研究。试验结果显示,送样316L不锈钢的耐腐蚀性能较00Cr17Ni14Mo2不锈钢的耐腐蚀性能差;316L不锈钢在乙醇制乙酸中的耐腐蚀性能低于在乙烯制乙酸中的耐腐蚀性能。上述试验为某化工厂生产设备的选材以及生产介质的选择提供了相应依据和参考。     

国外非API高耐蚀油套管品种开发现状

油套管服役条件日益复杂和严酷,具有更高耐蚀性的非API油套管应运而生。评述了JFE、住友金属、美国SMC镍合金集团和山特维克等国外先进钢管集团非API抗H2S应力腐蚀油套管、13Cr马氏体不锈钢油套管、双相不锈钢油套管和镍基合金油套管的品种开发现状,建议进一步加强开发非API高耐蚀油套管的力度。     

445M铁素体不锈钢缝隙腐蚀性能的研究

研究了445M铁素体不锈钢(%:0.004～0.005C、22.24～22.29Cr、1.10～1.65Mo、0.015～0.016P、0.003～0.004S、0.012～0.016N、0.22～0.38Ti)和316L奥氏体不锈钢(%:0.022C、16.80Cr、10.19Ni、2.02Mo、0.025P、0.001S、0.046N)在40～60℃氯离子浓度(250～5 000)×10^-6的氯化钠溶液的缝隙腐蚀性能。结果表明,445M铁素体不锈钢的耐缝隙腐蚀性能优于316L奥氏体不锈钢;当445M钢中的Mo含量由1.10%提高至1.65%时,钢的耐缝隙腐蚀性能明显提高,表明点蚀当量Cr+3.3Mo是衡量不锈钢耐点蚀和耐缝隙腐蚀的重要指标。     

304不锈钢表面冷喷涂TC4钛合金涂层性能研究

采用冷喷涂技术在304不锈钢表面制备了TC4钛合金涂层,通过扫描电子显微镜观察了涂层的形貌、组织结构,并利用电化学方法研究了涂层的腐蚀电化学特征。研究结果表明,冷喷涂制备的TC4钛合金涂层致密性存在较为明显的梯度现象,靠近基体的涂层密度明显高于表面;涂层喷涂过程没有出现明显氧化现象,与基体的结合强度可达20 MPa左右;涂层的耐腐蚀性能优于304不锈钢,可大大提升不锈钢材料在海洋环境中的耐点蚀性能。     

钢铁材料研发的技术进展

中国的钢铁材料研发活动越来越活跃,研发领域不断拓展,先进钢铁材料不断涌现。钢铁研究总院结构材料研究所致力于先进钢铁材料的研发,取得了显著的成绩。本文综述近年来的各个钢铁材料领域研发的技术进展,包括了碳素结构钢、高强度低合金钢、合金结构钢、超高强度钢、轴承钢、不锈钢及耐蚀合金、耐热钢及合金、工模具钢,以及相关技术等。通过持续的技术研发活动,钢铁材料已经和必将不断发展和更新,形成了以“高性能、低成本、易加工、高精度、绿色化”为特征的先进钢铁材料。     

耐候钢SPA-H的耐腐蚀性能研究

采用加速腐蚀试验方法研究了珠钢生产的耐候钢SPA-H的耐腐蚀性能。结果表明:在72h的加速腐蚀条件下,珠钢生产的耐候钢SPA-H的耐腐蚀性能优于国内A厂和B厂生产的同类钢种;高钙、低硫、高钛、少量珠光体组织,有利于提高钢的耐腐蚀性能。     

烧结碳化新工艺硬质合金的切削试验

对采用烧结碳化新工艺制取的硬质合金刀片进行了切削试验，结果表明，该刀片在车削奥氏体不锈钢，球磨铸铁和冷硬铸铁时，其耐磨性较好，与常规工艺生产的ＹＧ６刀片相当。     

超塑性奥氏体-铁素体双相不锈钢00Cr25Ni7Mo3N的研制

通过电弧炉-电渣重熔工艺开发研制了成分为(%):0.021C,24.16Cr,7.21Ni,2.87Mo,0.17N,0.48Cu超塑性双相不锈钢00Cr25Ni7Mo3N。试验结果表明,00Cr25Ni7Mo3N超塑性双相不锈钢的耐孔蚀性和耐缝隙腐蚀性远高于传统的304L和316L奥氏体不锈钢。在变形温度960℃、应变速率2×10^-3/s时,00Cr25Ni7Mo3N超塑性双相不锈钢的最高延伸率为960%,该钢超塑性变形的均匀性优于TC4钛合金,可显著减轻构件的重量。     

不锈钢“304”（06Cr19Ni10）及其衍生牌号的标准化学成分

“304”是美国的不锈钢牌号,我国与之对应的牌号是06Cr19Ni10）。该钢具有优良的不锈耐蚀性能,优良的冷热加工成型性能,较好的低温性能和良好的焊接性能。为了满足某些特定条件的使用要求,弥补性能上某方面的不足,发展出了一系列“304”的衍生牌号。表1～表6分别列出了ASTM、JIS、GB、ISO、EN不锈钢标准中304及其衍生牌号的牌号对照及各牌号的化学成分。     

合金钢的现状与发展趋势

在目前和可预见的未来,合金钢仍然是社会和经济发展所需要的重要材料。新型合金钢必须满足社会发展对钢铁生产、加工、使用和回收等环节提出的节约能源、节约资源、保护环境的要求,为此,合金钢将向高性能和多品种方向发展。本文概述了高强度低合金钢、合金结构钢、超高强度钢、不锈耐蚀钢、耐热钢、工具钢、模具钢、轴承钢等合金钢的现状和发展趋势。     

铈对S32550双相不锈钢微观组织及冲击性能的影响

 双相不锈钢兼具奥氏体和铁素体不锈钢的优良性能,多用于船舶、化工、核反应等领域。为了进一步提高S32550双相不锈钢的力学性能和抗腐蚀性能,采用真空感应炉成功冶炼了S32550双相不锈钢,并研究了有无添加稀土铈对其锻造、轧制后的微观组织、夹杂物形貌及冲击性能的影响。结果表明,添加稀土铈可以细化组织晶粒,使形状分布不均匀的铁素体组织与奥氏体组织均匀化;改善夹杂物形貌分布大小,对有害夹杂MnS进行改质,降低硫含量,使多余硫元素与铈反应形成Ce₂O₂S、Ce₂S₂夹杂弥散分布在钢中;另外,添加稀土铈可以提高S32550双相不锈钢在室温和低温(-40、-20 ℃)下的冲击韧性,在低温下可出现韧窝带,降低冷脆效应对钢材的危害。     

AOD精炼高氮奥氏体不锈钢1Cr22Mn15N的工艺实践

用 20 t AOD精炼成分(%)为1.84C ,2.18Mn ,24.88Cr的粗炼钢水 ,经吹O2 、N2 ,加电解锰、硅铁、铝块以及NCr合金成分微调 ,冶炼出(%) 0.12C ,0.42Si,14.96Mn ,0.026P ,0.001S ,22.57Cr,0.56N的高氮奥氏体不锈钢 1Cr22Mn15N。精炼钢水浇铸成590kg锭 ,初轧轧成 135mm × 157mm坯 ,再经连轧成Φ8～12mm的棒材。成品材固溶处理后的屈服强度为565～585MPa ,抗拉强度920～955 MPa ,延伸率为54.5 %～56.5% ,具有优良的耐腐蚀性能     

TTS443高铬铁素体不锈钢的开发

针对304(Crl8-Ni8型)奥氏体不锈钢和430(Cr17型)铁素体不锈钢的特性,通过试验和分析Cr、Cu、Nb、Ti等合金元素对铁基合金材料性能的影响,开发出一种高铬铁素体不锈钢-TTS443(/%:O.010C、21Cr、0.40Cu、0.25Nb、0.20Ti、O.012N) 。该钢种的耐蚀性能与304奥氏体不锈钢相当,具有良好的成形性与焊接性能,TTS443铁素体不锈钢是304奥氏体不锈钢理想代替材料。     

Friction Stir Processing for Enhancement of Wear Resistance of ZM21 Magnesium Alloy

Present work pertains to surface modification of the magnesium alloy using friction stir processing (FSP). Silicon carbide and boron carbide powders are used in the friction stir processing of the ZM21 Magnesium alloy. Coating was formed by FSP of the alloy by placing the carbide powders into the holes made on the surface. Surface coating was characterized by metallography, hardness and pin-on-disc testing. Friction stir processed coating exhibited excellent wear resistance and is attributed to grain boundary pinning and dispersion hardening caused by carbide particles. Surface composite coating with boron carbide was found to possess better wear resistance than coating made with silicon carbide. This may be attributed to formation of very hard layer coating of boron carbide reinforced composite on the surface of magnesium alloy. In the present work an attempt has also been made to compare the wear behaviour of surface composite layer on ZM21 Mg alloy with that of conventionally used engineering materials such as mild steel and austenitic stainless steel. Wear data clearly shows that wear resistance of friction stir processed composite layer is better than that of mild steel and stainless steel. This work demonstrates that friction stir processing is an effective strategy for enhancement of wear resistance of magnesium alloys.     

Microstructure and mechanical properties of a high strength and high corrosion resistance roll-bonded clad checkered plate

The checkered plate,also known as the floor/pattern plate,has a raised pattern that provides excellent skid resistance for a wide range of applications. As one of most commonly used products,the carbon steel checkered plate requires a high-cost coating for corrosion resistance. Although the austenitic stainless steel checkered plate meets corrosion resistance requirements,it does not necessarily provide high overall performance due to its low yield strength,which means greater thickness and weight. Combining the advantages of stainless and carbon structural steel,Baosteel has developed a new roll-bonded clad checkered plate that exhibits high performance in skid resistance,strength,and corrosion resistance. Metallographic analysis show s the cladding interfaces to be very good,with stainless steel filling the whole pattern and a uniform microstructure in the different cladding layers. The yield strength and tensile strength of the product are 470 MPa and 610 MPa,respectively. In addition,the fracture morphology exhibits excellent interfacial bonding properties. We performed external and internal bend tests at room temperature,180°,and 0.7a without the development of any cracks,which indicates its excellent formability.     

VODC产品的装备技术

随着市场对特殊钢质量要求的不断提高,尤其是对超低碳不锈钢、超合金、低合金特殊钢的要求的提高,一般设备较难达到要求;而通过VODC设备冶炼则容易些,且产出的钢材品质较其它设备要高;同时,因其较VOD设备增加了转炉功能,则为工艺过程中的测温、排渣、取样、出钢也带来了方便。     

Mn对2205双相不锈钢耐点蚀性能的影响

研究锰元素对2205双相不锈钢耐点蚀性能的影响, 锰质量分数的变化范围为0. 93%~1. 26%.分别采用化学腐蚀法、动电位极化法研究双相不锈钢2205的耐腐蚀性能, 采用夹杂物自动分析技术研究锰对钢中夹杂物种类及数量的影响, 通过扫描电镜、能谱及夹杂物原位分析法观察化学腐蚀及电化学腐蚀前后钢中夹杂物及其周围钢基体的变化情况.采用电感耦合等离子体发光光谱测定腐蚀产物的成分.研究结果表明, 不同类型的夹杂物对耐腐蚀性能的影响不同, (Mn、Si) 氧化物以及(Mn、Si、Cr) 氧硫化物在腐蚀液中更易溶解进而促进腐蚀, 而(Cr、Mn、Al) 氧化物却很稳定.锰的加入会促进钢中(Cr、Mn、Al) 夹杂的析出, 此类夹杂物不仅自身很容易被含Cl离子的溶液腐蚀, 而且作为点蚀的起始点, 促进了点蚀坑的形成, 加快了基体腐蚀, 最终导致不锈钢耐点蚀性能的下降.      

Solidification and microstructure of a high alloy stainless steel

The steel considered in the present work can be classified as a 6Mo austenitic stainless steel, which has a much higher corrosion resistance than many other commercially available stainless steels. However, because of macrosegregation during solidification of ingot casting, the high alloy content in the steel, especially Mo, N, C, enhances precipitation of intermetallic phases such asa phase. Such precipitation mainly occurs in the center of the material and has normally no significant effect on mechanical properties or surface corrosion resistance. The introduction of modern production methods such as continuous casting of slabs for stainless sheet production has reduced the macrosegregation tendency and related precipitation. However, the microsegregation in a small scale may be enhanced as the higher cooling rate prevents the diffusion in the solidified region. In the present work, the continuous casting solidification process was simulated in a laboratory gradient