计算机辅助设计(CAD)图解斜轧穿孔孔型开度值

介绍了一种使用计算机辅助设计(CAD)图解斜轧穿孔孔型开度值的方法,解决了在生产中用数学方法求解斜轧孔型开度值较复杂,难以应用的问题。对穿孔机轧辊空间位置进行计算机仿真后,作轧制线上某点的垂直截面,根据开度值假设条件,在截面内用作图方式逐步逼近开度值。以较简单的作图方式得到有一定精度、能满足工程应用的开度值,并对开度值数据作了简要的分析。     

斜轧孔型参数的可视化求解与数据分析

详细介绍了一种基于三维CAD设计软件的斜轧孔型参数的可视化求解方法,并以桶形辊穿孔机、锥形辊穿孔机和斜轧扩管机3种斜轧机型为例,介绍了孔型开度值、轧辊与轧件接触点处的速度矢量的求解步骤和求解过程,以及计算结果的验证方法;采用大量数据分析讨论了实际生产中轧机调整、轧辊返修对孔型开度值的影响。认为可视化求解法适用于所有斜轧机型的孔型参数分析,可为工具的设计提供更加准确的数据支持。     

斜轧扩管机孔型开度的研究分析

斜轧扩管机的空间结构不同于传统的斜轧管机。为了更好地掌握斜轧扩管机生产过程中母管沿变形区的尺寸变化规律,必须对轧辊辊面到轧制线的距离,特别是辊面到轧制线的最短距离即孔型开度值进行求解。依据斜轧扩管机特殊的空间坐标关系,利用平截面法求解斜轧扩管机轧辊辊面到轧制线的孔型开度值,并据此提出配套顶头的相关尺寸设计计算模型。     

锥形辊斜轧穿孔机轧辊开度值计算与分析

通过坐标变换和变量代换法建立了斜轧锥形辊穿孔机轧辊开度值的数学模型.利用MATLAB软件,研究了送进角与辗轧角变化对沿轧制线方向不同位置的轧辊开度值的影响.结果表明:轧辊孔型开度值随着送进角增大而增大,在同一送进角下,轧辊孔型开度值沿轧制线方向呈非线性变化,随辗轧角增大而增大;在同一辗轧角下,轧辊孔型开度值沿轧制线方向由非线性向线性变化.这能为穿孔机轧辊与顶头锥角设计和工艺参数调整提供理论依据.     

下压轧制的斜轧穿孔轧辊开度分析

斜轧穿孔机轧辊开度计算是轧机工具设计和调整参数计算的基础。文中分析了下压轧制条件下二辊斜轧穿孔机的轧辊开度,并讨论了轧辊开度的非对称性对穿孔过程及毛管壁厚均匀性的影响。     

金属水平连铸-连轧设备设计

在分析螺旋孔型斜轧工艺条件下金属的塑性变形规律、特点及金属的成形过程、坯料的咬入条件、螺旋孔型斜轧时轧件的运动规律等的基础上,将螺旋孔型斜轧工艺与水平连铸技术相结合,提出设计水平连铸-连轧设备的基本原理与方法.     

双金属复合无缝钢管斜轧过程的有限元分析

本文应用MARC有限元软件并采用三维热力耦合的弹塑性有限元法,对不锈钢/碳钢双金属复合无缝钢管斜轧过程进行了有限元分析,得到了坯料断面孔型变形图,分析得出了应力、应变与温度场的分布,根据数值计算结果绘制了管坯斜轧过程中辊缝下断面沿圆周的轴向应力、环向及径向应力分布曲线,并根据应力分布特点解释了钢管斜轧过程成形机理。研究成果可以为工艺参数的设计提供参考。     

异型管孔型设计的CAD组装法

借鉴活动板房设计、制造和组装的工艺流程,借助Auto CAD平台,从“圆形→异形”孔型变形曲线参数的设计、独立变形曲线的“制造”（画）和独立变形曲线的“组装”3个方面,介绍了异型管孔型的CAD组装法.提出充分利用CAD原则、逆向思维变形孔型原则、公称尺寸原则和流程化原则等.该方法省去了异型管孔型设计过程中的繁琐计算,使异型管变形合理,提高了孔型设计效率.     

图解计算法在管件焊胎设计中的应用

分析了管件焊胎设计计算时常用的图解法及模拟法的不足之处，介绍了利用图解计算法设计管件焊胎的新方法，该方法在设计计算复杂焊胎时方便而有效，值得推广。     

钢管斜轧延伸的金属变形研究及孔型设计(下)

简要分析了斜轧延伸轧管技术的发展。通过对AccuRoll轧管机变形区中金属变形的理论分析和试验研究,探讨了轧制工艺特征和工具对轧制变形的影响。并将计算机技术应用于变形区模拟分析和钢管主变形分析,提出了斜轧延伸孔型设计的基本原则。试验研究表明,通过AccuRoll轧管机的孔型设计,可实现减径、等径和扩径3种轧制形式。通过优化孔型设计,用AccuRoll轧管机轧制薄壁管,其D/S值已达到41。该工艺技术的发展将进一步提高轧制薄壁管的稳定性和轧制速度。     

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。