高强度桥梁缆索用钢研究现状和发展趋势

概述了国内外桥梁缆索用钢的发展历史;介绍了桥梁缆索用钢丝强度、扭转性能、耐腐蚀性等重要性能的研究现状;并从成分设计、盘条控冷工艺等方面论述了桥梁缆索用钢不同生产工艺的特点及未来发展的方向,为新型桥梁缆索用钢的研发提供借鉴。     

超高强桥梁缆索用多元合金锚固材料研究

桥梁缆索采用热铸锚方式锚固,具有强度高、耐久性好的优点,适于缆索百年服役的要求。分析了热铸锚的结构和锚固机理,合金锚固材料是影响热铸锚锚固性能和耐久性的主要因素,而Al,Cu,Mg,RE等成分和含量决定了合金锚固材料的性能。针对2100 MPa及以上强度超高强缆索,提出了热铸锚用合金锚固材料的物理性能、力学性能、防腐性能和流动性要求。根据这些影响因素和性能要求,建议按“性能指标构建-成分体系设计-模型试验研究-灌锚装备研发-灌锚工艺研究”的路线进行新型多元合金锚固材料研究。     

铜含量对超高强度低碳贝氏体钢力学性能的影响

实验用低碳贝氏体钢(%:0.042～0.045C、1.43～1.47Mn、1.0～2.5Cu、0.29～0.30Mo、0.025~0.029Nb、0.011~0.018Ti,0.0013~0.0023B)由50 kg真空感应炉冶炼。实验结果表明,随铜含量由1.0%增加至 2.5%,8-Cu在钢中沉淀速度加快,峰值硬度增大;随Cu%的增加,轧后直接淬火(DQ)钢的屈服强度由865 MPa增 至918 MPa, DQ+500℃回火钢的屈服强度由935 MPa增至1140 MPa,但1.0%~2.5%Cu DQ+500 ℃回火钢的抗 拉强度和冲击韧性均比DQ态钢有所降低。     

利用超低碳贝氏体开发的非调质高强度厚板

1　前言随着焊接构件的大型化和制作的高效化 ,要求强度、韧性、焊接性和经济性均优良的钢材。然而 ,为了提高钢的强度而增大其碳当量 (Ceq)时 ,会同时产生焊接 HAZ的硬化 ,从而增大钢的低温裂纹敏感性 ,降低钢的韧性。为了克服这些缺点 ,采用控轧和快冷相结合的 TMCP即热机械控制操作技术 ,进行了低 Ceq高强 (度 )钢的开发。然而 ,在原来的 TMCP技术中 ,钢的微观组织与冷速密切相关 ,而不能从钢板表面到板厚中心部都得到最佳组织 ,也就无法生产 50 mm以上的厚板。为了解决这些课题 ,生产厂家特别关注含 C量 (下记作〔C〕)在 0 .0 2 %…     

超高强度钢的应用与分析

对超高强度钢及其应用进行了论述，对超高强度钢的失效进行了分析，并提出了超高强度钢热处理工艺方案。     

高强度及超高强度双相不锈钢线材的应用

1前言如今在许多领域中双相不锈钢被视为经久耐用的代名词。这主要是南于双相不锈钢兼具高强度、高塑性和优异的耐蚀性能。同溶条件下的双相不锈钢其强度约为奥氏体不锈钢的两倍。SAF2205是一种传统中等合金含量的双相不锈钢,具有高的耐蚀、力学性能和良好的焊接性能。SAF2205和其他2205型双相钢牌号之间的不同在于SAF2205成分控制范围更窄。     

高强度低碳贝氏体钢DB-590的试制

在工业性试制的条件下 ,通过对热轧工艺的控制和调整 ,获得具有贝氏体组织特征的低碳贝氏体钢 ,该钢种具有高强度、高韧性的性能 ,并确定了其热轧工艺制度。     

550级超高强度海洋平台用钢的开发

介绍了实验开发成功的海洋平台用550级超高强船板的成分、性能特点和TMCP生产工艺,列举了钢板的实物性能,试验和分析了其焊接的适应性。研究结果表明,工业批量生产的550级超高强船板性能稳定,完全满足海洋平台用550级超高强船板的技术要求,已成功应用于建造海洋平台。     

高强度大桥缆索用盘条生产现状分析

最近5年,大桥缆索用镀锌钢丝抗拉强度有了大幅提高,从1 770 MPa级、1 860 MPa级、1 960 MPa级到目前的2 000 MPa及以上级别,扭转指标有了颠覆性的改变,从之前的几转到目前的十几转、二十几转。论述了国内外钢铁企业生产大桥缆索镀锌钢丝用盘条的不同现状。从成分设计、生产工艺流程、盘条韧化处理方式和组织特点等方面进行阐述,讨论了国内外不同生产工艺特点及发展趋势,为中国大桥缆索镀锌钢丝用盘条的生产提供理论支持。     

Structure-property changes during hardening and tempering of new ultra high strength medium carbon low alloy steel

Abstract

A medium carbon low alloy steel, electroslag refined, modified AFNOR 15CDV6, has been developed for satellite launch vehicle and related applications. Conventionally processed (without electroslag refining) mostly bainitic AFNOR 15CDV6 (with 0·15 wt-% carbon and ~ 3·5 wt-% other alloying elements) has a yield strength of ~ 800 MPa. Electroslag refining, coupled with increased carbon (0·29 wt-% carbon, but no change in percentage of other alloying elements), increased the yield strength to about 1300-1400 MPa, without sacrificing ductility. The microstructure of the modified grade was martensitic. Martensite in the as hardened state was mostly in the form of laths, although ~20% plate martensite was also observed. Until 150°C tempering, no noticeable loss of tetragonality was observed, while the unit cell parameter c/a ratio dropped to almost 1 after 300°C tempering. The interesting observation at 150°C tempering was the predominant presence of fine rodlike ? carbide, which may also explain the increased yield strength. Tempering above 150°C converted the ? carbide to cementite, relatively thicker precipitates of similar morphology. At higher tempering temperatures, no evidence of spheroidisation of cementites was noted. The highest tempering temperatures of 500 and 600°C resulted in two marked changes in the microstructure: the appearance of M₂₃C₆ type (Cr, Fe and Mo bearing) carbides, and the appearance of, in some regions of the microstructure at least, a relatively 'recovered' lath structure. Misorientation among adjacent laths, nearly constant at 8-9° until 450°C tempering, increased noticeably, to 13 and 16°, after the respective tempering temperatures of 500 and 600°C.     

高碳钢盘条的表面氧化与脱碳行为

By means of optical microscopy (OM) and scanning electrical microscopy (SEM), the effects of heating temperature and holding time on the surface oxidation and decarburization of two high carbon steel wire rods(82B and 87B) were investigated. The results show that with the increase of heating temperature??800-1150?棩, the speeds of oxidative mass loss (OML) of the two are slow firstly, quick afterwards and slow finally. The depth of total decarburization layer (DTDL) of 82B decreases to zero firstly and then increases sharply, while that of 87B exhibits a parabolic growth trend with the increase of temperature. With the holding time at 1050?? increasing from 10 to 80min, the speed of oxidative mass loss of 87B is quicker than that of 82B. DTDL of the two increase gradually with the increase of holding time. Change trends of 82B and 87B are almost the same during heating for a long time. By combining the observation of SEM, related theories and papers, the oxidation and decarburization behaviors of the two high carbon steel were analyzed and discussed.     

Research status of low carbon high strength bainitic steel

The research status of low carbon Si- Mn bainitic steel at home and abroad in recent years was summarized. The mechanism of bainite transformation and the formation process were introduced. By analyzing the effects of alloying elements on the properties and microstructure of low carbon Si- Mn bainitic steel, the partitioning behavior of alloying element Mn in the process of dual phase insulation was discussed and the strengthening mechanism of low carbon bainitic steel was revealed. Finally, the relationship between the technology, organization and properties of low carbon high strength bainitic steel was elaborated and several kinds of preparation techniques which can obtain yield strength and elongation higher than 1000MPa and 15% respectively were introduced. On this basis, the main research directions of low carbon high strength bainitic steels were prospected.     

拉丝用低碳钢热轧圆盘条标准与生产

结合唐钢拉丝用低碳热轧圆盘条生产工艺实际,通过理论分析与回归分析应用相结合,重新设计了内控标准中拉丝用盘条的化学成分,并有针对性地制定了炼、轧生产的工艺保证措施.     

Q345B低碳高强度钢的高温塑性

使用Gleeble3500热/力模拟机对Q345B低碳高强度钢的高温塑性进行了测定.通过透射电镜、扫描电镜及金相显微镜对析出物形貌、断口形貌和断口组织进行了观察,分析了Q345B钢的断裂机理.结果表明,在1 350~650 ℃范围内,明显存在3个区间,第Ⅰ区温度范围为熔点到1 307 ℃,断裂形式是由S、O等元素偏析引起的沿晶断裂;第Ⅱ区温度范围为1 307~920 ℃,由于动态再结晶的发生,断裂形式为穿晶塑性断裂;第Ⅲ区温度范围为920~650 ℃,断裂形式是由析出物钉扎晶界以及先共析铁素体析出引起的沿晶断裂.分析结论可为连铸生产提供理论依据.      

拉丝用低碳钢热轧圆盘条标准探讨

在对两个低碳钢热轧圆盘条标准进行对比的基础上,通过回归分析,讨论了LQ195、LQ215低牌号拉丝盘条的化学成分控制范围.     

子午线轮胎用钢帘线及其专用盘条国际标准的研制

综述了子午线轮胎用钢帘线及其专用盘条国内外技术发展趋势与现状,介绍了国际标准的研制工作的具体内容、创新点、经济和社会效益等,指出了以我国标准为基础制定国际标准的意义。     

30MnSi热轧盘条的开发与应用

根据广钢电炉冶炼、高线轧制的特点,通过合理的成分设计和生产工艺的制定,开发出PC钢棒用Φ8mm、Φ10mm规格30MnSi热轧盘条,产品性能满足下游工序的要求,并对头、尾力学性能波动进行了分析,提出了有效措施,稳定性明显提高．     

CT100高强度连续油管用钢卷的开发与应用

介绍了宝钢CT100高强度连续油管用钢卷的开发及应用。宝钢开发的CT100高强度连续油管用钢卷具有低的硫磷含量、均匀的显微组织、合适的力学性能,钢卷的屈强比低于0.80,且不同部位强度性能差异在50 MPa以内,符合连续油管的制造需求。采用研制的钢卷钢制造的连续油管各项力学性能均满足API Spec 5ST规范对CT100钢级连续油管的要求,且具有优良的抗疲劳性能。