用330mm方坯轧制40工字钢的孔型设计

1 前言为了改变初轧机轧制异形坯的不利局面,提高轨梁轧机的生产能力和40~#工字钢的成材率,配合实施我公司新制定的锭-坯-材工程表,我厂在采用330mm×300mm矩形坯轧制36~#工字钢的基础上,研制采用330mm大方坯轧制40~#工字钢。试轧表明,修改孔型设计是合理的,方案是可行的。40~#工字钢成品断面几何尺寸完全符合标准要求,达到了预期目的。     

国内外工槽钢生产技术及其发展（二）

万能轧制法的特点：可改善钢材表面质量，钢材尺寸精度高，比孔型设计法高出３０％以上；轧辊消耗低，比孔型设计法降低约２ｋｇ／ｔ材；轧辊共用性增加，用孔型法轧制普通工字钢，１套轧辊最多能轧１种型号３种规格的工字钢，采用万能轧制法，１套轧辊可轧制多种型号多种规格的Ｈ型钢或普通工字钢。轧制Ｈ型钢采用不同坯料时选用的孔型系统和孔型的设计方法如下：①采用方坯或矩形坯通常，Ｈ型钢腹板高度和翼缘高度之和＜４５０ｍｍ时，用方坯或矩形坯在二辊可逆式开坯机轧制，主要是使钢坯的形状与尺寸满足万能机组轧制的要求，在万能机架…     

24H新型矿用工字钢的切深孔设计

针对YB（T）24－86标准矿用工字钢截面设计的缺点，马鞍山钢铁股份有限公司开发了24H新型矿用工字钢，介绍了其孔型系统中切深孔的设计特点和保持轧制稳定性的措施。     

首钢长钢万能法轧制45~#工字钢的开发

介绍了首钢长治钢铁有限公司H型钢生产线自主开发45#工字钢的工艺方案、孔型设计和轧制规程设计,以及试生产过程中存在的问题及其改进措施,该45#工字钢的生产工艺稳定顺行,产品质量良好。     

我国H型钢供需预测

１前言Ｈ型钢是用万能型钢轧机轧制而成；因此也称万能工字钢或万能钢梁。由于不用孔型轧制，其腿（翼）比工字钢宽，前苏联称为宽腿（翼）或宽边工字钢。因腿内侧平行，没有斜度，欧美也有的称为平行腿工字钢或直腿工字钢。又因其形如英文字母“Ｈ”，日本定名为Ｈ型钢。与普通工字钢相比，Ｈ型钢腹高而薄，翼宽而内侧平行，重量轻，整体性能高，断面经济合理，规格多，使用方便，节约金属，且外形美观。因其抗弯强度大，适合用作柱子；因断面模数大，用于横梁可减小楼层间的高度。焊接Ｈ型钢以带钢或钢板为原料，经原料准备、焊接及精整等…     

扩腰孔型在连轧工字钢中的实际应用

介绍了采用半连轧工艺生产工字钢的工艺流程,根据现有连轧生产设备和工艺,对孔型系统进行了优化设计,将扩腰孔型应用到连轧工艺中,在同一套孔型中仅更换3个孔即可轧制不同规格的工字钢,降低了企业生产成本,增加了企业竞争力。     

工字钢在GREY四辊轧机上的轧制

引言克拉克夫矿冶大学金属成形过程研究室对工字钢生产的研究已进行了许多年,自1968年起,工作重点就集中在设计合适的孔型,以及H型钢在四辊轧机上轧制的工业性生产上。研究成果发表在波兰的许多学报、科学著作和研究报告中。工字钢生产在全世界冶金工业中一直在发展,但在我国的生产中,仍存在着亟待解决的问题。本论文综合了我们在四辊轧机上轧制技术取得的成就。     

立辊喂钢机的应用

立辊喂钢机的诞生我厂生产的产品有工字钢、槽钢、等边角钢、不等边角钢、轻轨、鱼尾板、汽车轮辋、U型钢、π型钢等20余个品种,100多个规格的中型钢材,年产量达65万吨。使用90×90～145×145毫米方坯及部分扁钢坯,经7～9道次轧出成品,由于轧件在第一架轧机轧制道次多,在由下轧制线升到上轧制线时,升降机起落一次需2.06秒,同时第一架轧机轧辊的线速度也比第三、四架轧机低,轧制周期一般在11～12秒,每小时只能轧制300余支钢,限制了生产能力的提高。以7.5号角钢为例,各道次的轧件长度、轧件通过轧槽所用的时间列于表1。     

哈萨克斯坦阿克托比新建轨梁轧机

西门子金属技术公司接到哈萨克斯坦阿克托比轨粱公司的订单,要求新建一套轨梁轧机。新轧机将建在阿克托比镇,由哈萨克斯坦国家铁道公司给予赞助。新轧机每年将生产约20万t的最大长度为120m的钢轨和23万t的角钢、u型钢和工字钢。西门子将提供完整的轧制生产线。     

莱钢小H型钢线R2粗轧机空过的实践

为降低生产成本,山东钢铁股份有限公司莱芜分公司小H型钢生产线在生产某些规格H型钢和工字钢时,采用了不使用R2粗轧机,即R2粗轧机空过的轧制方式。并以H100 mm×100 mm H型钢为例分析了其可行性,介绍了R2粗轧机空过后的孔型设计、有限元模拟、现场生产情况以及生产过程中的技术难点及解决措施。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

电化学噪声数据处理方法概述

综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。