双线双活套控制器

我厂由意大利意巴斯高公司引进的小型轧机可生产φ6～20mm圆钢、10～20mm螺纹钢。年产钢材14×10~4t,坯料为90～120mm方坯及连铸坯,坯长3000mm。设有开坯机φ450×1,轧制5道次,其余为连轧机各轧1道次:φ420×2、φ360×4、φ320×4、φ280×6、φ260×2(分为2线)。在中轧机设有5个双线双活     

采用小异型坯生产大规格H型钢的技术研究

介绍了首钢长钢轧钢厂采用等宽的连铸异型坯(430mm×300mm×85mm×80mm)开发轧制H300mm×300mm×10mm×15mm规格H型钢的过程。为了使成品的翼缘宽度能够达到300mm,在开坯机孔型中增加了较大的凸度,在减小对翼缘压下的同时增加了对腹板的压下,以利于万能轧机轧制时翼缘的宽展。此外,还制定严谨的试轧方案,针对试轧制中出现的问题、缺陷,特别是开坯机孔型中增加了较大的凸度后,轧制时H型钢圆角部位易出现折叠的问题,重新优化了开坯机孔型、万能孔型及轧制工艺,消除了折叠缺陷,产品力学性能满足标准要求。     

450mm热连轧机组轧制带钢拓宽分析

讨论了邯郸钢铁公司一轧厂450mm热连轧带钢的拓宽问题；对该机组及其φ500mm开坯机进行了现场测试，并在计算机上进行了带钢拓宽模拟轧制，得出了该机组的最大轧制负荷及其带钢的拓宽限度。     

衡阳华菱钢管有限公司成功轧制φ740mm×75mm无缝钢管

2012年7月19日,衡阳华菱钢管有限公司φ720mm周期轧管机组首次成功轧制出45钢φ740mm×75mm无缝钢管．成功突破该机组生产极限规格。     

2.3 t铸锭的奥氏体气阀钢轧制工艺探索及生产

研发了2.3t铸锭的5Cr21Mn9Ni4N(21-4N)奥氏体气阀钢轧制开坯工艺.热模拟此钢种在高温状态的抗拉强度Rm和断面收缩率Z,并根据生产设备功能状态,分析确定了适合该奥氏体气阀钢2.3t铸锭轧制开坯的温度范围,以及相应的初轧加热工艺制度和初轧机压下规程及轧制方法.对轧制能力与热剪机能力的验算,确认Φ750 mm初轧机、650 t热剪机等设备具备轧制2.3t铸锭生产160 mm×160 mm奥氏体气阀钢的可行性.产品质量满足奥氏体气阀钢线材盘卷单重≥1.5t的供坯需求,实现了规模化轧制生产.新工艺较大幅度地降低了吨钢生产的天然气消耗和动力电消耗、有效地降低了生产成本.     

横列式400轧机的阶梯和诱导辊道设计

我厂轧机采用φ400×2/φ300×5横列式布置形式,分别用1000、1250kW电机驱动;轧机线速度分别为2.5、5.6m/s(精轧机列五架单独650kW电机拖动,线速度6.16m/s)。用60、75mm方坯生产φ16～45mm圆钢及φ16～40mm螺纹钢筋。主要钢种为低合金钢、普碳钢和优质碳结钢。加热炉有效尺寸为19×3.714m,采用侧出钢。不同产品规格在400机列轧制道次不同,其中φ16～25mm产品轧制5道;φ32～40mm产品轧制3道。随着生产的发展。我厂小型轧机几经改     

φ720mm×800mm热轧机试验机组的研制

介绍了我所设计的φ720 mm×800mm热轧机试验机组,并着重介绍该机组所采用的推钢翻钢装置、机架辊装置等新技术及其新装备。     

小型扁钢连轧基本要求和轧机调整

小型扁钢连轧和轧制其它小型材一样,其工艺设计除应满足连轧常数为定值的基本要求外,还应考虑前滑系数、拉钢系数、轧制工作辊径的选用、轧件实际截面积的计算和轧辊转速调整等重要因素。现根据实践中的体会对上述因素的影响分析如下。我厂四车间工艺布置如图1所示,共有五个机列,第1机列φ300×2、第Ⅱ机列φ300×1为粗轧机组;第Ⅲ机列φ250×5,其中两架为过渡机架,第Ⅳ机列为φ250×1;     

TA2钛管加工工艺优化

为了简化φ89 mm×2 mm的TA2钛管加工工艺路线以及提高生产效率,通过改变管坯规格和减少轧制道次的方法,对原始工艺进行了优化.经过对挤压比、开坯轧制力和开坯轧机模具的承载能力进行校核,确定了较优的工艺路线.经过工艺优化,φ89 mm×2 mm钛管生产的原材料损耗减少了约1％,轧制道次减少了1道次,设备资源利用率显著提高,模具磨损减少,生产效率提高了3倍.     

天津钢管集团股份有限公司φ720mm机组成功轧制φ530mm孔型钢管

2009年2月1日天津钢管集团股份有限公司φ720mm机组一次轧制成功中530mm×10mm流体管。该规格钢管为石化系统急需的产品。φ720mm斜轧扩径机组自2008年6月投产以来,已成功采用φ508,610,559mm^3种孔型,轧制了8个品种、近40个规格的钢管。这次新采用的是φ530mm孔型,     

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).     

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.     

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.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.