中国含钒低、微合金化钢的开发与前景

介绍了钒在低、微合金化钢中的作用以及钒微合金化钢的重点产品;回顾了中国低、微合金化钢的开发情况;阐述了中国开发含钒微合金化钢的前景。     

钛微合金化高强钢的研究与发展

简要回顾了国内外钛微合金化高强钢的发展历程,详细论述了700 MPa以上级别钛微合金化高强钢的研发现状,着重阐述了钛微合金化高强钢中纳米碳化物析出行为(形变诱导析出与相间析出)的研究现状,并分析了钛微合金化技术的发展趋势,旨在进一步完善钛微合金化物理冶金学理论,为钛微合金化高强钢的发展和工业应用提供一定的指导。     

钢中稀土与铌、钒、钛等微合金元素的相互作用

介绍了钢中稀土与微合金化元素的相互作用,微合金化元素可以增大稀土在钢中的固溶量,稀土可以细化钢中微合金元素沉淀相,增强微合金化元素在钢中的作用。     

Nb微合金化H型钢控制轧制技术研究

用热模拟试验方法确定了Nb微合金化H型钢生产工艺参数，介绍了马钢Nb微合金化H型钢生产工艺和Nb微合金化H型钢达到的实物质量水平，同时对马钢生产的H型钢和国外同类产品的性能做了对比，马钢Nb微合金化H型钢具有良好的强韧性。     

微合金化与控制轧制的进展

文章概述了微合金化对改善钢的组织、提高钢的性能的作用;介绍了微合金化钢的成分设计及几种新的轧制工艺。     

钒微合金化钢的技术进展与应用

摘要：介绍了钒微合金化技术的最新进展以及钒钢的开发与应用情况。氮是含钒钢中有效的合金元素,含钒钢中增氮,优化了钒在钢中的析出,显著提高沉淀强化效果。采用钒氮微合金化设计,配合适当的轧制工艺,促进V(C,N)在奥氏体中析出,起到了晶内铁素体形核核心作用,实现了含钒钢的晶粒细化。最新的研究成果表明钒微合金化可以提高双相钢、贝氏体钢、相变诱导塑性钢、孪晶诱导塑性钢、热成型马氏体钢等汽车用先进高强度钢的强度并改善使用性能,显示出良好的应用前景。钒氮微合金化技术在中国高强度钢筋、高强度型钢、非调质钢、薄板坯连铸连轧高强度带钢等产品中获得广泛应用,大大促进了中国钒微合金化钢的发展。     

中碳微合金化钢高温延塑性的研究

借助Gleeble1500热模拟试验机测试了含Nb和含Nb、Ti两种中碳微合金化钢的高温力学行为,分析了析出物、相变、动态再结晶对微合金化钢高温延塑性的影响。结果表明:试验钢种无第Ⅱ脆性区出现;含Nb钢第Ⅲ脆性区的温度范围为950~700℃,含Nb、Ti钢第Ⅲ脆性区的温度范围为900~725℃;微合金化元素Ti的加入可以细化奥氏体晶粒使含Nb微合金化钢高温塑性槽变窄、变浅;析出物沿晶界多而细小的析出和γ→α相变是第Ⅲ脆性区微合金化钢高温延塑性变差的主要原因。实际生产中通过优化二冷区水量,采用弱冷,可以有效降低微合金化钢表面微裂纹的发生率。     

低成本钛元素合金化超高强度钢的组织及力学性能

针对低成本超高强度钢的开发问题,在国外材料基础上设计开发了低成本Ti微合金化超高强度钢,弥补了国内相关产品空白;同时通过力学测试、微观组织表征、析出相分析等方法揭示了Ti微合金化对试验钢的组织性能影响规律及强韧化机制,为低成本超高强度钢板新材料的工业化应用提供数据积累与理论支撑。试验结果表明：Ti微合金化试验钢与基础钢相比,屈服强度相当,断面收缩率从33%提升至44%,低温冲击韧性也从22.6 J提升至26.7 J,可见Ti微合金化试验钢具有更好的塑韧性匹配;其主要原因是Ti微合金化试验钢中有较多的MC型和M₃C型碳化物析出,使得基体中固溶的C质量分数从0.287%降至0.247%,同时Ti微合金化使得试验钢的原奥氏体晶粒由9.5级细化至11.0级,有效晶粒尺寸从1.8μm降低至1.3μm。计算结果显示：Ti微合金化试验钢碳当量较基础钢明显降低,因此焊接性能更好;Ti微合金化试验钢通过降低固溶强化、提高位错强化和细晶强化以及析出强化,实现了屈服强度的提升,并保障了韧性和工艺性能。     

钒氮元素在钢中的特性及对工艺影响的探讨

介绍了钒氮微合金化钢中微合金化元素钒、氮的行为机理，探讨了钒氮微合金化强化机理及热轧工艺的技术特点。     

VN元素在微合金化钢中的作用和开发前景

论述了VN元素在微合金化钢中的作用和钒钢中增氮最经济可靠的方法。指出VN微合金化技术在高强度焊接钢筋、非调质钢、薄板坯连铸连轧高强度板带和第三代TMCP工艺中的应用。强调了VN微合金化钢的研发和推广应用。     

Roles of microalloying elements on the cluster formation in the initial stage of phase decomposition of Al-based alloys

In age-hardenable aluminum alloys, nanoscale clusters composed of solute atoms and vacancies are formed and play very important roles in microstructure control and alloy properties. The microalloying elements in the aluminum alloys affect the cluster formation and resultantly precipitate microstructures. The fundamental effects of microalloying elements on Al-Cu, Al-Zn, Al-Li-Cu, and Al-Mg-Si alloys are demonstrated through changes in the electrical resistivity, hardness, differential scanning calorimetry (DSC), and microstructural evolution. In order to understand the complicated effects of microalloying elements, a Monte Carlo simulation model was developed and performed. In the simulation, it was found that some microalloying elements preferentially trap quenched-in excess vacancies to retard cluster formation in the initial stage of aging. The complex clusters of solute/microalloying element/vacancy were found to be formed in the subsequent stage and act as effective nucleation sites for clusters and Guinier-Preston (GP) zones. The roles of microalloying elements are well understood in terms of the ordering parameters and are well predicted based on the ordering parameter maps (OP maps) proposed in this work.     

Nb-V、Nb-Ti对重型热轧H型钢强韧性的影响

随着大型桥梁、高层建筑、海洋石油平台等的建设需求不断增加,翼缘厚度80 mm以上的重型热轧H型钢具有可观的市场前景。受其生产设备及工艺的影响,80 mm厚重型热轧H型钢的强韧性提升难度极大,微合金成分体系设计无疑是有效的突破点之一。对Nb-V、Nb-Ti成分体系对重型热轧H型钢强韧性的影响进行了对比研究。结果表明,Nb-Ti与Nb-V微合金化试验钢晶粒尺寸相当,但Nb-Ti微合金化试验钢的铁素体体积分数比Nb-V低约8%;Nb-Ti微合金化试验钢屈服强度、抗拉强度比Nb-V低30 MPa,-40 ℃低温冲击值比Nb-V低127 J;第二相粒子为Nb(C,N),分布均匀,随着合金元素添加量的增加,第二相析出数量增加,质点半径增大。     

Efficient steel processing by disciplined hot forming and microalloying

The application of thermomechanical treatment (TMT) is an example for an efficient way of steel processing. However, decisive for this is the fact that the course of the microstructural processes in hot rolled steels is not determined exclusively by the deformation parameters, but in a strong way by the material itself. The addition of microalloying provides an efficient way of enhancing the effect of TMT on the microstructural processes. The choice and dispensing of individual microalloying elements in hot rolled steels depend on desired properties and parameters of TMT. On the other hand, in most cases, the TMT must be modified to make full use of microalloying. In this paper, some general guidelines are given for an optimized link between the hot deformation and microalloying of steels. Using the example of the processing of a spring steel, the common effect of TMT and microalloying leads to a significant increase in fatigue strength, combined with a notable shortening of the manufacturing process.     

中国铌微合金化钢发展方向

对近年来我国微合金化技术的发展进行了评价，分析了在微合金化钢开发中的一些问题，并指出今后3－5年内研究和开发的方向。     

Effect of Cooling Rates on the Second‐Phase Precipitation and Proeutectoid Phase Transformation of a Nb–Ti Microalloyed Steel Slab

During the continuous casting of low‐carbon Nb–Ti microalloyed steel, control of the slab surface microstructure and the behavior of the second‐phase precipitation are significantly influenced by the cooling rate. Through confocal laser scanning microscopy, the effect of the cooling rate on the behavior of ferrite precipitation both at the grain boundary and within the austenite was observed in situ and analyzed. The relationship between the cooling rate and precipitation of the microalloying elements on the slab surface microstructure was further analyzed by transmission electron microscopy. The results showed that the effect of microalloying element precipitation on proeutectoid ferrite phase transformation is mainly manifested in two aspects: (i) the carbonitrides of microalloying elements act as inoculant particles to promote nucleation of the proeutectoid ferrite and (ii) the carbon near the grain boundary is depleted when the microalloying elements precipitate into carbonitrides, inducing a decrease in the local carbon concentration and promoting ferrite precipitation.     

微合金化对高碳钢成分偏析影响的实验室研究

以铬微合金化为基础,主要研究钒、铌、钛及其交互作用对高碳铸坯宏观组织、凝固偏析的影响,为微合金元素应用于高碳钢提供实验依据。实验表明,铌在加入量范围内对枝晶有强烈的细化作用,显著影响碳偏析,随铌量的增加则碳偏析减小;钒一元微合金化,钒、铌二元微合金化,钒、铌、钛三元微合金化,随钒量的增加则碳偏析明显减小;钛在加入量范围内对碳偏析影响不明显,但却能明显减轻锰的偏析;钒、铌、钛在不同程度上均可减轻锰、硅、硫的偏析。     

HRB400钢中钒微合金化工艺改进

介绍了钒微合金化的强化作用原理及工艺改进，用钒氮合金代替普通钒铁合金冶炼HRB400钢，通过对微合金化工艺改进前后化学成分、物理性能的对比，钢材性能进一步提高。     

复合微合金化对SiMn3型贝氏体钢力学性能的影响

研究了用少量Ｍｏ，微量Ｖ，Ｂ，Ｒｅ进行复合微合金化，对低碳ＳｉＭｎ３型贝氏体高强钢力学性能的影响。结果表明，复合微合金化可显著提高其空冷状态的韧性，明显改善低温韧性，并可显著提高回火抗力和高温回火后的强度。     

浅谈建筑用热轧带肋钢筋的应用现状

针对我国新颁布的热轧钢筋生产标准,本文在V/V-N微合金化、Nb微合金化以及细晶粒钢筋技术等技术领域,简要介绍了我国热轧钢筋的应用现状。