双排辊冷轧管机的研究

介绍了双排辊冷轧管机的工作原理和主要特点。进行了冷轧钢管实验。多次现场实验表明，采用所研究的双排辊冷轧管机能够实现大减径量和大减壁量轧制，并可轧制薄壁钢管，已轧制的成品钢管规格有Φ25mm×2．5mm和Φ19mm×0．9mm，产品质量符合国家标准。该轧机的研制成功可为我国现有冷轧管机的改造提供一条有效途径。     

对小规格冷轧管机发展的设想及实践

对小规格冷轧管机的发展方向提出了四项措施：（１）采用不停车上料;（２）采用二辊式冷轧管机;（３）采用多辊的双排辊轧制;（４）采用多排辊式冷轧管机。     

弯辊矫直过程变形机理研究

以无初始变形铝板为研究对象，采用数值解析法对弯辊矫直变形机理进行了分析，并建立了不同弯辊量下的矫直过程计算模型。通过ABAQUS有限元仿真模拟和19辊矫直机进行了弯辊矫直过程实验，在相同压下量，弯辊量为0.1、0.2和0.3 mm下，研究了矫直过程中弯辊量对板带浪形的影响。结果表明：相同压下量，板带矫直后浪形高度与弯辊量成正比变化，而浪形纵向周期长度与其呈反比变化；实验数据、模型计算与理论计算的结果误差范围在15%以内，处于合理误差之内。     

冷轧管机发展中有关技术问题的讨论

对二辊式、多辊式冷轧管机发展中的几个关键技术问题进行了理论探讨和比较;对冷轧管机主参数系列、机架行程长度、曲柄转向、同步齿轮分度圆直径、同步齿轮模数、单双回转送进及多辊式冷轧管机轧辊数目的选取等进行了分析和比较;提出了设计建议。还推荐了一种新型的轧管机平衡系统即双偏心块齿轮平衡系统及多辊式冷轧管机机头圆定心结构。     

圆钢切分导卫装置的设计

对圆钢切分轧制高精度控制进行了探索 ,得出入口导卫采用双排导辊结构 ,对孔型采用与轧件等圆弧进行设计 ,扭转导卫采用扭转体结构 ,扭转角误差为± 0 5° ,切分导卫采用悬臂式结构 ,切分轮顶角设计为 95° ,调整间隙为 0 15～ 0 30mm时 ,能较好地满足圆钢切分轧制的控制要求     

一种双排辊高效冷轧管机投入工业化生产

乌克兰 Ｓｉｍｙ Ｆｒｕｎｚｅ公司与 Ａｄｖａｎｃｅｄ Ｔｅｃｈｎｏｌｏｇｉｅｓ ｆｏｒ Ｔｕｂｅ Ｍａｋｉｎｇ Ｃｏ．公司共同开发出双排辊 ＸΠＴ－９５型高效冷轧管机并投入工业化生产。该冷轧管机能生产尺寸偏差极小的钢管：直径偏差仅为±（０．０４～０．０７）ｍｍ,壁厚偏差仅为ｔ（２～３）％。轧辊为串联布置,双排轧辊将变形区长度增大了１．７～１．９倍。每排辊均配置独立的主动齿轮,从而增大了对轧件的允许压下量（直径从９６ｍｍ压缩到３２ｍｍ;从７６ｍｍ压缩到２５ｍｍ）。排辊的轴向压缩力虽使管子的强度减少了２０…     

十一辊全液压中厚板矫直机弯辊模型研究

在中厚板矫直过程中,可以根据经验值来反映弯辊量和压下量、板材参数之间的关系,创建经验值数据库管理程序、神经网络操作程序和OPC与WinCC通信程序,这三部分组合成弯辊量模型操作软件.该软件具有经验值添加、删除功能,调用经验值训练神经网络功能,利用训练过的神经网络根据板材参数计算相应弯辊量的功能及将计算得到的弯辊量传递到WinCC监控画面的功能.该模型软件具有自学习和自计算功能.     

支承辊镶套修复

针对大型支承辊采用堆焊修复而使辊面组织不均匀的问题,采用了支承辊镶套修复技术,根据支承辊的使用情况设计镶套轧辊的配合直径及联接过盈量,根据配合直径及过盈量确定热装温度,保证安装顺利进行.支承辊镶套修复后,镶套轧辊联接紧固,可以满足支承辊使用性能.实际使用中效果良好.     

基于FNN的中厚板矫直机弯辊量自适应整定

中厚板矫直过程是一种多变量、非线性及压下量和弯辊量相互耦合的过程,很难建立完全反应实际矫直过程的数学模型.本文提出了基于模糊神经网络的弯辊量自适应整定模型,其在实际的应用过程中不依赖具体的数学模型,能很好的解决非线性、时变、强耦合的问题.实验研究表明,此弯辊量自适应模型具有很好的整定效果.     

LD-120Ⅲ型五辊冷轧管机在咸阳石油钢管钢绳厂投入使用

<正> 由西安重型机械研究所设计,上海彭浦机器厂制造的LD-120Ⅲ型五辊冷轧管机最近在咸阳石油钢管钢绳厂投入生产。该机是目前国内最大的多辊厚壁精密冷轧管机。该机是在LD-120五辊冷轧管机基础上重新设计的。在重新设计中根据LD-120冷轧管机长管坯长行程的特点,对机头芯棒卡盘、回转送进箱、动平衡机构、气囊离合制动器等多处作了较大改进,并首次使用了计     

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.     

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.