运用大孔出流理论设计滚筒铸铁件顶雨淋浇注系统

梳棉机用锡林滚筒,材质HT200,轮廓尺寸φ1 318 mm×1 150 mm,壁厚22 mm,铸件重1260 kg,表干砂型。内外表面加工。为了防止铸造缺陷,运用大孔出流理论设计顶雨淋浇注系统;用收缩模数法校核浇注系统当冒口的补缩能力。设计结果：1只直浇道φ70 mm,圆环形横浇道截面50/60 mm×50 mm。批量生产表明：铸件没有气孔,夹渣及缩孔等缺陷,工艺出品率94%。实践证明：采用大孔出流理论设计浇注系统,收缩模数法校核其补缩能力,实现浇注系统当冒口的工艺是可靠的。     

细纱机箱体铸铁件顶雨淋浇注系统充填补缩一体化设计

FA528型细纱机箱体铸件,材质HT200,轮廓尺寸840 mm×736 mm,主要壁厚12 mm,最大壁厚30 mm,重236 kg,呋喃树脂自硬砂型.用大孔出流理论设计浇口杯一内浇道二单元顶雨淋浇注系统,用均衡凝固收缩模数法核算浇注系统的补缩能力.设计结果：长盆形浇口杯上宽60 mm,下底宽30 mm,长430 mm;下设7只φ14 mm雨淋内浇道,在浇注系统的对侧设置溢流排气冒口.经3 800件批量生产验证,铸件没有冷隔、浇不足、缩孔、气孔类铸造缺陷.表明采用均衡凝固收缩模数法计算铸件的补缩是实用、可靠的.     

运用均衡凝固理论设计液压机上横梁底雨淋式浇注系统

400 t液压机上横梁,材质HT200,铸件重4 670 kg,主要壁厚55 mm,轮廓尺寸1 818 mm×1 262 mm×730 mm,普通粘土砂手工造型,干型、干芯。运用大孔出流理论设计底雨淋式浇注系统,直浇道直径φ85 mm,位于55/65 mm×52 mm横浇道中间,两侧横浇道上均布12 mm×60 mm、长40 mm底雨淋内浇道共14只。用均衡凝固收缩模数法核算浇注系统当冒口的补缩能力。生产结果表明,铸件没有气孔、夹砂、夹渣、收缩等铸造缺陷,铸件品质稳定。实测浇注时间平均92 s,与计算值偏差1%,工艺出品率94%。生产实践证明,采用大孔出流理论设计浇注系统,用均衡凝固收缩模数法校核浇注系统的补缩功能,可以满足铸件充型和补缩要求,具有实用价值。     

运用均衡凝固模数法设计铸铁箱体补缩式浇注系统运用均衡凝固模数法设计铸铁箱体补缩式浇注系统

轧环机下箱体，材质HT250，重9500kg，轮廓尺寸4100mm×2500mm×577mm，干砂型，冲天炉熔炼。运用均衡凝固模数法设计补缩式顶注雨淋浇注系统，以大孔出流作充填校核。采用2个浇包同时浇注，2套独立对称的浇注系统，设计结果为：直浇道φ80mm，横浇道56／60mm×50mm，18只内浇道φ18mm，浇注温度1320-1380℃。浇注出的铸件形状完整，机加后没有缩孔、缩松、夹渣、气孔等缺陷，工艺出品率93％。表明均衡凝固模数法设计补缩式浇注系统是实用的。     

运用均衡凝固模数法设计铸铁箱体补缩式浇注系统

轧环机下箱体,材质HT 250,重9 500 kg,轮廓尺寸4 100 mm×2 500 mm×577 mm,干砂型,冲天炉熔炼.运用均衡凝固模数法设计补缩式顶注雨淋浇注系统,以大孔出流作充填校核.采用2个浇包同时浇注,2套独立对称的浇注系统,设计结果为:直浇道φ80 mm,横浇道56/60 mm×50 mm,18只内浇道φ18 mm,浇注温度1 320～1 380 ℃.浇注出的铸件形状完整,机加后没有缩孔、缩松、夹渣、气孔等缺陷,工艺出品率93%.表明均衡凝固模数法设计补缩式浇注系统是实用的.     

耐热球铁深入煤斗铸件浇口冒口工艺设计

箱体类耐热球铁深入煤斗铸件,轮廓尺寸1 920 mm×890 mm×330 mm,璧厚25 mm,材质RQTSi-5.5,重740 kg。粘土砂干型,内腔顶面分型,铸件主要在下型,浇注系统座在芯头上。采用大孔出流理论进行充填设计:1只直浇道φ69 mm,位于横浇道中间,横浇道截面44 mm/54 mm×56 mm,6只内浇道110 mm/130 mm×6 mm。在浇注系统对面设2只溢流补缩耳冒口。用均衡凝固收缩模数法设计计算冒口,直径70 mm,高100 mm。批量生产,生产结果,没有工艺缺陷,生产稳定可靠,工艺出品率93.7%。证明采用大孔出流设计浇注系统,均衡凝固收缩模数法设计耐热球铁箱体类铸件的补缩系统是可靠的。     

抽油机曲柄铸铁件浇注系统当冒口的工艺设计

14型抽油机曲柄,材质HT200,轮廓尺寸3 162 mm×690 mm×250 mm,主要壁厚160 mm,两侧均布铸齿,铸件重1 982 kg,要求组织致密,不允许有缩孔、缩松、气孔、冷隔等缺陷.干砂型,冲天炉熔炼.为了防止铸造缺陷,用大孔出流理论设计顶注式浇注系统,用收缩模数法校核浇注系统当冒口的补缩能力.在曲柄的一端开设4只30/22 mm×52 mm梯形内浇道,56/68 mm×73 mm梯形横浇道位于上箱,在横浇道中间设置Ф60 mm直浇道,在铸件顶面设置12 mm×60 mm扁出气孔6只.在连接孔处安放半圆形冷铁.批量生产60余件,铸件没有冷隔、浇不足、气孔、缩孔和缩松缺陷,工艺出品率97.7%,表明工艺实用、可靠.     

大型船用柴油机铸齿飞轮均衡凝固工艺设计与计算

船用柴油机铸齿飞轮 ,材质HT3 0 0 ,外形尺寸 3 172mm× 3 91mm ,最大壁厚 3 91mm ,最小壁厚 40mm ,质量 11.5t,模数 8.1cm。采用均衡凝固工艺 ,大孔出流理论计算浇冒口尺寸 ,浇注时间 118s ,采用开放底注式浇注系统 ,内浇口为 2 9只 2 2mm的陶瓷管 ,环形横浇道加陶瓷雨淋过滤网 ,直浇道采用 10 0mm陶瓷管 ,6只 12 0mm× 2 90mm腰圆形缩颈冒口 ,配合 5 0mm×60mm溢流集渣槽。浇注铸件经机加工 ,装机运转 ,达到设计要求。     

浇注系统和冒口联合补缩消除球铁镶圈铸件缩孔缺陷

锻压机用球铁镶圈铸件,牌号QT450-10,外径φ2 364mm,内径φ2020mm,厚120mm,重995kg。为了防止铸件产生铸造缺陷,运用均衡凝固理论,采用顶注、内浇道分散引入、浇注系统和冒口联合补缩工艺。直浇道φ80mm;双向梯形横浇道,上底35mm,下底45mm,高50mm;内浇道宽50mm,厚8mm,长10mm,共24只。在浇注系统的对面安放侧冒口1只,直径φ180mm,高350mm;冒口颈宽220mm,厚20mm,长10mm,用于溢流和补缩。经批量生产验证,铸件内无缩孔、缩松缺陷,上表面无渣孔、气孔缺陷,工艺出品率81%。实际证明：采用均衡凝固理论设计球铁圈形铸件的补缩系统是可靠的。     

YJ231接装机后墙板铸铁件浇注系统当冒口的补缩和溢流排渣设计

YJ231接装机后墙板铸铁件,材质HT200,轮廓尺寸1102mm×962mm×34mm,重200kg,干砂型,表面质量要求高,6个面均需机加工。为获得无夹渣、夹砂、缩松、气孔等缺陷铸件,采用均衡凝固浇注系统当冒口,浇注和补缩一体化设计方法:1只直浇道φ40mm,双向横浇道截面梯形32mm×44mm×50mm,4只内浇道80mm×7mm搭接在铸件顶面,设2只溢流排渣冒口φ50mm×60mm,8只出气冒口φ20mm。墙板实际浇注时间28s,与计算值吻合。生产实践证明,运用均衡凝固浇注系统当冒口浇注、补缩和溢流排渣工艺稳定可靠。     

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。