高强度低合金钢晶粒细化理论及技术

论述了高强度低合金（HSLA）钢晶粒细化理论及强度提高途径，综述了高强度低合金（HSLA）钢晶粒细化技术及近年来的研究成果，探讨了超细晶技术的理论依据及存在问题。为高强度低合金钢组织超细化技术的理论研究和实际工程应用提供参考。     

降低低合金高强度H型钢生产成本的研究与实践

为了提高该公司低合金高强度H型钢产品的性能,降低生产成本,增强产品的竞争力,提高企业的经济效益和生产效率,通过对该公司生产的低合金高强度H型钢的生产工艺、组织、性能等特点分析,找出了产品性能不合的原因,主要是元素C、Si、Mn、微合金V元素的含量及控轧控冷工艺的影响,在实践中通过采用合理的合金成分设计与控轧控冷工艺相结合,保证低合金高强度H型钢力学性能符合产品标准,产品质量合格。     

形变热处理

来自能源、建筑和运输工业的经济压力,迫使世界钢铁界着手开发比传统淬硬钢和回火钢成本更低的新型高强度钢。由于高强度钢是在热轧状态使用,所以在完成主要的热变形过程以后就无需进一步热处理了。这种钢取决于几种强化机理的配合:结构细化、弥散硬化、固溶强化。所谓的高强度低合金     

超高强度钢研究进展及其在军事上的应用

简要地介绍了近年来超高强度钢的发展以及国内外低合金超高强度钢和二次硬化超高强度钢的研究进展，介绍了300M、30XгCH2A、AF1410、Aemet100等国外几种典型钢种和国内新研制的G99和G50钢的力学性能和主要特点，并探讨了我国超高强度钢的发展方向和研究重点，以及这些钢在军事上的应用前景。     

航空高强度钢原材料和热加工的缺陷及改进措施

为了提高飞机的性能,航空零件尽量选用比强度高的材料,所以航空工业中广泛使用多种低合金高强度钢(σ_b≥110公斤/毫米~2)。高强度钢主要用于制造受力较大的重要承力件,该件往往形状复杂,服役条件苛刻;而高强度钢     

大线能量焊接条件下低合金高强度钢针状铁素体形核影响因素及形核机理研究

综述了大线能量焊接条件下低合金高强度钢中针状铁素体形成的研究进展,概述了针状铁素体显微组织结构特点及其在低合金高强度钢中的主要性能,具体讨论了针状铁素体具有良好强韧性和抗断裂性等力学性能的原因,重点分析了大线能量焊接条件下影响焊接热影响区中针状铁素体形核长大的因素,包括合金元素及夹杂物的种类和尺寸,得出针状铁素体的形核机理是多种机理联合作用的结果。     

航空用新型超高强度钢AF1410

虽然中碳低合金超高强度钢应用很广,使用经验丰富,但这并不能弥补它的不足之处。这类钢的断裂韧性低,抗应力腐蚀性能差,焊接性能不太好,不能在中温下使用。由于钛合金在比强度方面可与当前的超高强度钢相媲美,某些使用性能优于高强钢,所以重要受力结构件部分被钛合金所代替。但是钛合金工艺性能差,价格昂贵,零件成本极高,扩大使用受到很大限制。如果能找到一种材料兼有上述两种材料的优点,即既具有一般中碳低合金超高强     

正火及高温回火对低合金高强度铸钢组织和性能的影响

正火和高温对铸钢材料具有很大的关系,文章根据铸钢的特点,设计了低合金高强度铸钢的实验,并研究分析了低合金高强度铸钢的显微组织、低合金高强度铸钢的力学性能以及比较了实验铸钢和低合金高强度铸钢的性能,最后做出总结。     

低碳低合金钢临界区加热时的相变过程

本文评述了近年来低碳低合金高强度钢在Ac_1～Ac_3间的临界区内加热时奥氏体形成方面的文献资料,并且提出了尚待研究的问题。     

高强度低合金钢的药芯电弧焊

手工电弧焊、埋弧焊,气保护钨极电弧焊和气保护金属极电弧焊工艺已广泛用于焊接高强度钢。近十年药芯焊丝研究的进展促使开发出某些用于焊接标准高强度钢以及较新型的高强度低合金(HLSA)钢的新型药芯焊丝。本文介绍了有关这些新型药芯焊丝的机械性能、焊缝金属扩散红量和所要求的焊接工艺等方面的技术资料。并将利用特定的焊接应用实例从经济角度讨论药芯电弧焊方法的优点。     

Zum Einfluss des Schweißens auf das Kriechverhalten moderner Stähle für die thermische Energieerzeugung

The influence of welding on creep behaviour of modern steels for thermal power generation Un‐ and low alloyed ferritic/bainitic Chromium steels as well as high alloyed ferritic/martensitic 9–12 % Chromium steels are widely used for high temperature components in thermal power generation. Welding in all its variety is the major repair and joining technology for such components. The weld thermal cycle has significant influence on the base material microstructure and its properties. The Heat Affected Zone is often regarded as the weakest link during high temperature service. While weldments of un‐ and low alloyed ferritic Chromium steels can show significant susceptibility to Reheat Cracking in the coarse grained heat affected zone, weldments of high alloyed ferritic Chromium steels generally fail by Type IV Cracking in the fine grained heat affected zone during long term service. In this paper the influence of the weld thermal cycle on the base material microstructure is described. Long‐term creep behaviour of weldments is directly related to the main failure mechanisms in creep exposed ferritic weldments and implications for industries using heat resistant ferritic steels are shown.     

Mechanical properties of a carbide-free bainitic cast steel with dispersed free ferrite

ABSTRACT

A high silicon, medium carbon cast steel was designed and heat-treated in order to develop microstructures composed of carbide-free bainite and small amounts of free ferrite, with the aim of obtaining high strength cast steels with improved ductility. Because of microsegregation, it was observed that ferrite present in partially austenitised samples is mostly present at the highly alloyed zones, creating an interconnected network even for low proportions of this phase. Despite the coarse solidification structure and marked microsegregation in the cast steel, the mechanical properties obtained for both fully bainitic and bainitic-ferritic microstructures largely satisfy the minimum standard requirements for high strength cast steels and are similar to those reported for wrought steels of similar microstructures.     

Advanced cold rolled steels for automotive applications

Advanced multiphase steels offer a great potential for bodies‐in‐white through their combination of formability and achievable component strength levels. They are first choice for strength and crash‐relevant parts of challenging geometry. The intensive development of high‐strength multiphase steels by ThyssenKrupp has led to hot dip galvanizing concepts with an outstanding forming potential. Hot rolled, hot dip galvanized complex phase steels are currently produced in addition to cold rolled DP and RA steels. New continuously annealed grades with tensile strength levels of up to 1000 MPa in combination with sufficient ductility for applications mainly in the field of structural automobile elements make use of the classic advantages of microalloying as well as the principles of DP and TRIP steels. Further improvement of properties will be reached by the new class of high manganese alloyed steels.     

Carbide types in an advanced microalloyed bainitic/ferritic Cr–Mo Steel – TEM observations and thermodynamic calculations

The strength and toughness of low alloyed ferritic/bainitic steels depend on their microstructure, which evolves during thermo‐mechanical treatments along the processing chain. Chromium‐molybdenum steel microstructures are complex. Therefore, only a limited number of attempts have been made to fully characterize carbide populations in such steels. In the present work, analytical transmission electron microscopy is employed to study the microstructure of a low alloyed chromium‐molybdenum steel, which features ferritic (F, mainly α‐iron and niobium‐carbides) and bainitic (B, α‐phase, dislocation, grain/subgrain boundaries, various M_xC_y carbides) regions. The crystal structure and chemical nature of more than 200 carbides are determined and their distributions in the two microstructural regions are analyzed. The present work shows how particles can be identified in an effective manner and how the microstructural findings can be interpreted on the basis of thermodynamic calculations.     

海洋耐蚀钢的国内外进展

随着陆地资源日趋枯竭,海洋资源的开发与利用被列为2l世纪的重点目标之一。耐海水腐蚀材料的研究和应用是海洋开发的基础和前提,其中海洋耐蚀钢研究应用成为热点。海洋耐蚀钢主要指应用于原油运输船、海洋平台、海底油气管线和大型跨海桥梁等领域的一类低合金高强度钢,在海洋开发和利用领域应用量大、涉及面广。结合国家海洋事业发展"十二五"规划,对海洋耐蚀钢的需求作了简要分析;在总结油船货油舱内部腐蚀环境及机理的基础上,综述了日本、韩国、乌克兰、俄罗斯和中国在油船货油舱用耐蚀钢方面的研究开发现状;比较了美国、日本、法国和中国研发的耐海水耐蚀钢的特点;指出了我国在油船货油舱用耐蚀钢及耐海水腐蚀钢方面存在的问题、差距和对策;提出了我国发展海洋耐蚀钢需要解决的关键技术与核心科学问题。     

氮对淬火-配分超级马氏体不锈钢组织和性能的影响

对超级马氏体不锈钢进行氮合金化并进行淬火-配分工艺处理,使用OM、SEM、TEM、EBSD、BSD、万能试验机和维氏硬度计等手段对不含氮和氮含量(质量分数)分别为0.23%、0.35%的三组超级马氏体不锈钢进行表征,研究了氮元素对其组织和性能的影响。结果表明：氮的添加细化了实验钢中的马氏体板条,使其平均宽度由2.93 μm减小到0.65 μm。在配分处理过程中较高的氮富集度为逆变奥氏体的生成提供了驱动力,并使其稳定到室温。在钢中添加氮元素使钢的强度和塑性均明显比0 N试验钢的高,0.23 N和0.35 N试验钢的抗拉强度和延伸率分别为1510 MPa、24.2%和1215 MPa和35.1%。由此可见,氮合金化有利于提高超级马氏体不锈钢的力学性能。     

The effect of σ-phase precipitation at 800°C on the mechanical properties of a high alloyed duplex stainless steel

High alloyed duplex stainless steels, referred to as super duplex, are being used increasingly for applications in corrosive environments. The higher Cr and Mo contents of these materials can lead to susceptibility to σ-phase precipitation, even during short time exposures to high temperatures. The 800°C aging of a high alloyed duplex stainless steel was investigated. Optical microscopy with image analysis, X-ray diffraction, and SEM were used to determine the σ-phase and to estimate the amount. Mechanical properties such as tensile strength, impact strength and hardness were investigated. It was found that the impact strength is most sensitive to aging at 800°C. The σ-phase transformation is discussed and the microstructural aspects are described.     

ODS ferritic steel engineered with bimodal grain size for high strength and ductility

An attractive way to enhance the ductility of ODS ferritic steels is to develop an alloy with a bimodal grain size distribution, in which the micron-sized coarse grains provide high ductility. The nanometer-sized fine grains enhance the tensile strength. The microstructures were obtained by blending the gas-atomized powders and mechanical alloyed powders, followed by hot forging and annealing. The homogeneously distributed nanometer-sized oxide nanoparticles can also be detected. Mechanical properties tests revealed a great improvement in ductility in comparison with other ODS ferritic steels, and high strength over the whole range of test temperatures, owing to the fine grains and oxide nanoparticles. The combination of high ductility and high strength makes this ODS ferritic steel much promising in high-temperature application.     

On the effect of Temperature Cycling on the coating of a pack aluminized low alloyed steel (13 CrMo 44)

Coated pack aluminized low alloyed steels are known for their good resistance against high temperature corrosion up to 700 °C, where diffusion stability is still sufficient. In typical high temperature applications, coating and substrate are subjected to thermal fatigue. In this study the metallurgical stability of a coated, pack aluminized, low alloyed steel is reported. The specimens were cyclically quenched from 700 °C to room temperature or liquid nitrogen temperature respectively, to assess the importance of thermal shock severity on the kinetic of degradation. In particular, crack initiation and growth were studied. The dependence of microcrack densities upon numbers of cycles, cooling rates and specimen geometry is reported.     

核聚变堆包层结构材料研究进展及展望

随着人类对能源需求的增加,核聚变能的发展越来越受到人们的关注。材料问题是目前限制聚变能发展的一个重要因素。包层是实现能量转换、氚自持及辐照屏蔽的主要部件,满足包层结构材料苛刻环境要求的结构材料的开发及性能检测成为目前研究的热点。以低活化铁素体马氏体(RAFM)钢为代表的包层结构材料已发展多年,然而依据中国聚变能发展路线图,CFETR一期包层结构材料的中子辐照水平可达到约10dpa,在二期达到约50dpa,目前没有材料能满足包括抗辐照损伤在内的苛刻环境要求并能满足工程建设需求。低活化铁素体马氏体钢是目前包层结构材料的首选候选结构材料,国内外已开发了多个牌号的低活化品种并具备了丰富的材料基础数据库,然而低活化钢的工作温度区间严重受限,高温蠕变及抗辐照能力无法满足CFETR二期及未来聚变堆的要求。为解决传统RAFM钢的不足,提出了两条思路:一种是添加氧化物弥散相以有效提高高温蠕变强度,其中又以制备过程中是否涉及机械合金化可进行进一步的区分;另一种思路是基于热力学模拟计算,优化RAFM钢化学成分并进行多轮热机械处理以增加MX相密度。其中,机械合金化制作的氧化物弥散强化钢(ODS钢)的性能最佳,但受限于机械合金化法,成本高且效率低。非机械合金化ODS钢与优化的RAFM钢的性能接近机械合金化ODS钢,成本远远低于机械合金化ODS钢且制备效率高,大批量制备技术相对容易。除了铁基材料外,钒合金及碳化硅复合材料在多方面展现了优势,长期以来都是研究人员关注的热点。钒合金的热蠕变和氦脆导致温度上限低并且与氢同位素兼容性不好,碳化硅复合材料的规模化生产及连接技术仍存在困难,这些缺陷限制了钒合金与碳化硅复合材料的发展,使之在现阶段无法满足应用需求。面向更高辐照水平的示范堆及商用堆,目前已有的包层结构材料可能无法满足需求。根据目前很有限的研究数据,非晶材料及高熵合金的工程应用还非常遥远:一方面需要借助材料设计和制备的新理念、新方法不断挖掘现有材料的性能潜力,另一方面应重视具有潜在优势的复合块状非晶材料及低活化高熵合金等新型材料的研发。本文依据中国磁约束聚变材料路线图草稿,对RAFM钢、机械合金化制备的ODS钢,钒合金以及碳化硅复合材料的发展进行了综述,对最近几年兴起的改良RAFM钢、非机械合金化制备的ODS钢等新型候选结构材料进行了介绍,并对具有更佳性能的先进结构材料种类进行了展望。