车板造型的合箱操作技术

车板造型是用车板分别车制出各箱砂型,再通过一定的合箱技术进行合箱,完成全部造型操作的.如果合箱操作技术不好,就容易使铸件产生错箱等缺陷,严重影响铸件质量.车板造型的合箱操作方法主要有冒口合型法、圆线合型法和十字线合型法等.本文介织车板造型的合箱操作技术.     

自动翻箱合箱装置在V法生产线中的应用

V法铸造生产中翻箱、修型及合箱是影响造型线生产率和造型质量的一个重要环节,本文介绍了一种全自动在线翻箱合箱装置,对其结构特点和工作过程进行了阐述,并介绍了该装置在生产中的应用.     

手工造型箱锥定位的生产应用

手工造型生产中，砂箱的定位十分重要．据粗略统计，我厂几年中因砂箱定位不准确使铸件产生错箱缺陷的约占报废铸件的55％。以往曾用过多种定位方法，其使用效果均不够理想，主要是可靠性差，而且操作也比较麻烦。后摸索出用箱锥定位的方法，取得了很好的效果。定位箱锥是由箱锥锥体和锥座模所组成（见图1、图2），均由机加工成形。其使用特别简单，造型时先用锥座模在下箱造出箱锥锥座，然后插人箱锥锥体，再造上箱锥孔，锥座模和锥体的脱模均很容易。合箱时先将锥体插人上箱的锥孔中，对正下箱的锥座即可完成合箱，如图2所示。／般造型有2…     

多层砂箱造型翻箱法

多层砂箱造型翻箱法济南试验机制造总公司科协（济南２５００２２）周庆海在造型生产中，当遇到较高的模样而又没有合适的砂箱时，就需要用多层砂箱来代替，有时会用两层、三层、四层砂箱造型，这样就给翻箱带来较大困难。用传统的翻箱方法，需要用紧固螺丝把几层砂箱合紧...     

自硬树脂砂无箱造型工艺实践

通过对自硬树脂砂各项工艺特性的分析，大胆利用其型砂高强度的特性，省去金属砂箱，用固化后的砂型直接合箱浇注，称为无箱造型。     

机械化砂箱造型铸件最大错箱值的控制

采用图解的方法，根据射压造型合箱的实际，推导出控制铸件最大错箱值的计算公式。将其用于实际生产，取得了预想的精度控制效果。     

一条20型/h浴缸V法铸造生产线

我公司2005年承接了河南天瑞集团制造生产年产10万吨V法造型生产线（20型／h）的任务，该造型生产线核心部分——上下箱造型圈的覆膜器、翻合箱机械手、造型转运车、造型真空梁及电器系统等由德国HWS公司制造生产，我公司在接受消化新技术新工艺的同时为该生产线配套生产了造型线的辅助转运系统，如辊道输送机、真空梁、转运车、推缓缸、液压系统、翻箱机等，2006年底该生产线已顺利通过用户验收并投入正式生产。     

动态合箱机

使用连续式铸型输送机的造型线具有造型生产率高,动力消耗少,设备简单等优点,因此造型线的成本低,运行可靠,故障少,维修和管理容易。但是,采用连续式铸型输送机时必须解决动态下完成提箱、落箱、合箱、取放压铁以及下芯、浇注等关键工艺。完成以上工艺过程的必要设备为动态辅机,其中动态合箱机最具有典型意义。我国的造型线大多数均采用连续式     

一种新型车板造型方法

针对传统车板造型过程中,按十字线标记合箱容易产生操作误差而导致错箱废品,提出了一种采用卯榫定位结构的新型车板造型方法,该方法尤其适合中、小件黏土砂造型工艺。     

转臂的铸造工艺与生产控制

针对转臂铸钢件在生产过程中出现的底部夹砂、尺寸不合格,下芯后底部散砂不易清理,造型翻上盖箱时易塌箱,下芯后合上盖箱过程中,支臂处大芯子对上砂型阻挡较严重,造型合箱操作较困难等现象,对原工艺进行了改进.并通过加强工序过程的质量控制,设计合理的外冷铁和借助模拟软件验证等措施,最终生产出高质量的合格铸件.     

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。