钢轨余热强化新工艺新技术开发

介绍了钢轨余热强化新工艺新技术开发及其用于钢轨强化的性能水平、工艺特点及同世界上其他工艺的钢轨余热强化性能比较。     

钢轨化学成分对力学性能影响的研究

为全面了解鞍钢生产的钢轨的化学成分和力学性能的情况,对2004年7月～2005年2月鞍钢生产的钢轨的化学成分和力学性能进行了统计分析.结果表明,鞍钢生产的钢轨化学成分范围较窄,力学性能相对稳定,成分的变化对性能有一定的影响.通过调整化学成分,可进一步提高钢轨的力学性能.     

喷嘴与钢轨间距离对喷风冷却效果的影响

通过采用ANSYS FLOTRAN流体软件模拟钢轨喷风冷却热处理过程中流场的速度分布,以及钢轨热处理实验,分析了喷嘴与钢轨之间的距离对钢轨热处理后硬度的影响。喷嘴与钢轨之间的距离在15～20 mm范围时,钢轨热处理后硬度分布最好,热处理效果最佳,为钢轨在线热处理生产线的建设提供了理论基础。该流场模型模拟结果与试验结果完全一致,为钢轨喷风冷却热处理工艺的优化提供了一定的指导作用。     

加热炉半热滑轨的数值分析

在钢坯的加热过程中,为了有效地减弱或者消除钢坯的水管黑印,在加热炉的加热段和均热段一般采用半热滑轨或全热滑轨,滑轨端面温度对加热质量及钢坯在炉内的安全运行起着至关重要的作用,而端面温度取决于滑轨的高度和截面形状。结合工程实例,建立了相应的物理数学模型,采用数值分析的方法对不同高度下半热滑轨的温度场进行了计算,结果表明滑轨端面温度与其高度呈现出对数函数关系,在应用中梯形滑轨优于矩形滑轨。     

法国高速铁路用钢轨的生产技术及国内存在的差距

介绍了法国高速铁路钢轨的生产技术，包括钢坯的冶炼、钢轨轧制、精整及质量检测以及成品钢轨性能质量特点，同时介绍了目前国内钢轨生产情况以及与之相比存在的差距。     

铁路用钢轨及其制造技术

总结分析了货运铁路和客运铁路用钢轨的典型成分体系与性能,阐述了铁路用钢轨在冶炼、连铸、热轧等制造流程中存在的关键技术问题,以及该技术在国内外的新进展,着重分析了万能轧制技术制造铁路用钢轨的特点及其关键技术。从成分体系开发、制造技术等方面分析了国内铁路用钢轨的生产现状及质量水平。     

Al-Zn-Mg-based cast alloys having high mechanical properties

The effect of alloying elements and heat treatment on the structure and properties of cast alloys based on the Al-Zn-Mg system and containing more than 9% (Zn + Mg) is analyzed. The optimum chemical composition of an alloy from this system is determined, and the heat-treatment conditions required for improving the mechanical properties of the alloy are found.     

Transformation of defects in continuous-cast billet during rail production

Defects of continuous-cast billet and their transformation at different stages of rail production are studied. It is found that, on many occasions. longitudinal surface cracks in the billet (of shrinkage or groove type) do not lead to the formation of surface defects on rails, whereas crystallization cracks accompanied by slag inclusions or closure of the metal may be transformed to rolling cracks or blisters on rolling.     

客运专线用100米钢轨矫直断裂原因分析

 客运专线用100米60kg/m重轨在焊轨厂拼焊后,当四面矫直时发生断裂。采用光学显微镜及扫描电镜（TEM）等方法对钢轨矫直时断裂原因进行了分析和研究。结果表明：钢轨断裂是由于距钢轨端部约100mm轨底边缘处存在凸台缺陷,此凸台在钢轨拼焊后进行除瘤时除瘤刀将其铲平,致使钢轨产生冷裂纹,进而在矫直时断裂。通过控制万能精轧上下辊的辊径差以及调整轧制线高度等方面,使钢轨出轧机时尽量保持平直,避免上翘或扣头,从而消除凸台缺陷的产生。     

Improving the reliability of welded joints in bulk-quenched electrosteel rail

Metallurgical methods of improving the reliability of the weld seam in bulk-quenched electrosteel rail are considered: optimization of the chemical composition in terms of the basic elements and total impurity content; improvement in plastic properties of the rail by reducing the hardness; and removal of nonmetallic inclusions from the steel. Instability is seen in the weldability of the rails and also in the composition, with the same set of mechanical properties. The need for improvement in welding technology is shown; without the elimination of existing problems, the weldability of electrosteel rail cannot be guaranteed.     

提高重轨质量的途径

本文从国内重轨钢的冶炼(包括：铁水预处理、转炉的终点控制、炉外精炼、连铸)、重轨的轧制、热处理工艺技术和设备所存在的质量问题和条件，提出了改善包钢重轨质量的措施，同时研究了高速(200km／h)轨的技术条件以及包钢开发生产高速轨的建议。     

Differential heat treatment of rails

Experimental data are presented regarding the differential quenching of rails in air and the properties of the first batch of differentially quenched rail (length 100 m) subjected to certification tests. The prospects for the new class of rails are assessed.     

轧辊材料及其热处理工艺发展的现状与趋势

在轧钢技术快速发展的过程中，对具有长寿命、高可靠性的高性能轧辊的需求也在日益增长．文章综述国内外轧辊材料及其热处理工艺在各个阶段的研究与应用情况，介绍通过优化钢的化学成分和改进热处理方式来提高轧辊性能的途径、几种新型材料的化学成分与性能特点，最后对轧辊材料的选用及热处理方式进行了展望．     

Growth of the production of rails from continuous-cast semifinished products of electrical steel

Since 2001, the Novokuznetsk Metallurgical Combine has produced 3.0 million tons of R65 railroad rails of continuous-cast steel made in electric furnaces. The combine has significantly improved all the most important quality indices of the steel during this period, and the service life of the rails has increased from 0.5·10⁹ to (0.8–1)·10⁹ tons gross. The combine has mastered the production of rails with superior cold resistance and rails suited of use in high-speed rail systems. It is beginning production of rails with a bainitic structure and rails made of hypereutectoid steels. All these results have been obtained through the construction of new production facilities and modernization of the combine’s existing equipment. Plans for future rail production include extensive reconstruction of the heat-treatment section of the rail-beam shop and reconstruction of the machine-tool bay, the latter involving replacement of part of the equipment. Arc steelmaking furnace No. 1 and two continuous casters will be rebuilt in the electric steelmaking shop. The ultimate goal is to increase the durability and reliability of the rails so as to put them on par with the best rails in the world.     

Composition and properties of the diffusion layer formed upon heat treatment of an aluminum gas-thermal coating on titanium

An aluminum gas-thermal coating 200–300 μm thick is deposited onto the surface of titanium samples with an arc discharge. After heat treatment of the samples at 900 or 1000°C for 2, 4, or 6 h, the chemical composition and properties of the diffusion layer formed as a result of titanium and aluminum interdiffusion are studied. The main phase of the diffusion layer is found to be TiAl₃. The fractions of the phases TiAl₂, TiAl, and Ti₃Al are insignificant. The adhesion of the diffusion layer to the titanium substrate, the wear resistance, the friction coefficient, the hardness, the corrosion resistance, and the thermal and electrical conductivities are studied as functions of the heat-treatment temperature and time.     

国内外热处理钢轨性能分析

主要介绍了国内外几个主要厂家生产的全长热处理钢轨的实物性能，对国内外几种全长热处理钢轨的实物性能检验分析表明，我国攀钢ＰＤ３含钒微全金热处理钢轨的综合机械性能最好；攀钢ＰＤ２碳素热处理钢轨综合性能指标不亚于国外同类热处理钢轨；日本ＤＨＨ铬合金在线热处理钢轨的硬度、强度与离线碳素热处理钢轨相当，但韧性略低。     

New pearlitic steels for 21st century rail applications

To improve competitiveness,the nation’s railroads have increased the axle loads and speed of the trains.This has led to a rapid decrease in the life expectancy of premium rails through accelerated wear,rolling contact fatigue and fracture.To counter this effect,the railroads need rails that exhibit better performance in these areas.A research program has been initiated to study the microstructural aspects of near-eutectoid steels that would improve these properties.The first phase of the work was to carefully characterize the existing commercial rail steels in terms of pearlite interlamellar spacing,steel cleanliness and the presence of pro-eutectoid cementite on prior-austenite boundaries.These characterizations were then correlated with both mechanical properties and overall rail performance.The second phase of the program was to develop a better microstructure through control of composition,thermomechanical processing and cooling path.This was achieved through the use of laboratory-melted heats of experimental near-eutectoid compositions and a computer controlled MTS compression machine modified for axisymmetric compression testing and subsequent controlled cooling.The optimum processing route for these new steels has been determined,and pilot-scale heats have been melted,hot rolled and cooled using the information gained from the MTS investigations.The mechanical properties of these new steels have been determined and the rail performance tests are being conducted using laboratory-scale evaluation.Ultimately,these new rail steels will be tested under commercial conditions on the TTCI test track in Pueblo,Colorado.This paper will report on the alloy and processing design and resulting properties of the steels developed in this research program.Guidelines for future rail compositions and processing to obtain improved properties and performance will be presented.     

Introduction of a new bar-rolling mill

An up-to-date bar-rolling shop has gone into operation at AO ArcelorMittal Temirtau. The production of rolled bar and complex profiles, including the rolling and splitting of rebar profiles 8, 10, 12, and 14, has been successfully introduced. The rolling mill is equipped with a Thermex system for heat treatment of the profiles (thermomechanical strengthening). Optimal rolling and heat-treatment conditions are established for rebar produced from imported Стзсп and Стзпс steel billet. The products fully comply with strength class At400 according to State Standard GOST 10884-94.     

钢轨的质量要求与包钢钢轨生产的质量控制措施

根据我国铁路高速重载的特点 ,分析了钢轨的质量要求 ,论述了包钢连铸工艺生产钢轨的技术特点和质量控制措施 ,结论认为 ,包钢钢轨具有较高的纯净度 ,各项性能较好 ,轧制工艺设备技术改造完成后 ,包钢可具备批量生产高速轨的能力。     

连铸坯轧重轨的压缩比及帽形孔和切深孔的应力场分析

对某厂所使用的重轨孔型自切深孔以后的轧件压缩比进行了分析，对帽形孔和切深孔中沿轧件横断面上的应力场分布进行了弹塑性有限元计算机模拟。结果表明，用连铸坯取代初轧坯，如果坯形和孔形不进行相应的改变，轧件轨头和轨底的压缩比小，难以确保重轨的质量。现有的孔型，沿轧件的横断面上，局部位置存在着较大的拉应力。使用初轧坯，这种拉应力对产品质量的影响不大。但对于连铸坯，如果坯形和孔型均与初轧坯相同，轧件有产生内部缺陷的条件。