塑料检查井注射模型腔板刚强度与轻量化研究

利用ANSYS软件建立塑料检查井注射模型腔板刚强度有限元分析模型,研究2种不同结构对型腔板刚强度的影响。结果表明:壁厚值为200 mm时,型腔板1、2的刚强度相差不大,但型腔板2的质量远小于型腔板1;型腔板2的刚强度变化趋势为:随着壁厚值的增加,型腔板所受到的应力应变值先减小后增大,壁厚为60 mm时应力应变值最小,壁厚为120 mm时应力应变值趋于稳定状态。     

钢模型腔超塑成形与电火花复合加工

钢模型腔的电火花加工是常用的型腔加工技术 ,但加工效率较低。型腔超塑成形是型腔加工新技术之一 ,但需用高温合金凸模 ,且成形后需淬火强化而影响已成形型腔的精度。介绍了将2种技术优化组合的复合加工原理、实施方案及应用实例。该技术尤其适用于有批量要求的复杂高精度型腔的加工。     

旋扭压胶模的型腔冷挤压加工

我厂产品中的热固性塑料旋扭如图1所示。压胶模结构如图2所示。其中顶件器7的上平面比型腔6的底平面高0.3mm,是防止多次出模磨损而使型腔与顶件器之间间隙增大。由于型腔镶件6的型腔较复杂,故采用冷挤成形,取得了良好的效果。现将加工过程介绍如下。     

大型注塑模具设计理论基础(五)

<正> (2) 矩形型腔底板厚度的确定 一般说来,型腔底板厚度由模具结构决定,不须专门计算,但有时须将模腔置于动模边、以模脚支撑而被悬空此时其底板厚度必须通过计算确定。按照矩形型腔结构的不     

电铸模具型腔

日本家用电器产品的模具加工,除采用先进的数控设备加工外,还采用电铸法加工塑料模具型腔。塑料模具型腔采用电铸镍成形,电铸型腔壁厚一般在5mm 左右,电铸周期在10天之内,电铸时电压3～4 V,电流2～3A/dm~2,电铸凹模型腔表面硬度 HV250～300,几何型腔尺寸精度可控制在2～3μ,光洁度可达到▽10～12。电铸成形后,凹模外形进行修正,镶入标准模架框内,空隙处可用环氧树脂或其他金属填补加固。采用这种工艺制造塑料模具,     

国外模具文摘

<正> 该模具用于以注射法成形泡沫塑料制件。模具由两部分组成,如图半模1,可以在四根导柱2上移动。在型腔6中预先伸入了两个活塞7和8,以改变型腔的形廓。熔融塑料通过主浇道3及分浇道4和5充填型腔,充满之后内活塞8降至与7平,然后一起降至型腔最低处。由于发泡塑料是逐步填充型腔,所以可成形高质量的厚壁件,而且各断面组织均匀。图3。     

注射模型腔强度计算

大型塑料模具型腔侧壁强度是模具设计中的一项重要工作。通过对蓄电池槽模具型腔受力分析,根据模具型腔的强度,危险截面校核,变形量验证等进行了计算,对型腔设计中不足之处,提出了型腔凹模锁模块结构设计,能防止型腔的变形,并进行了验证,保证了模具型腔设计的安全、可靠、经济。     

阻焊快速成型材料与堆焊层质量研究

在阻焊快速成型材料与工件之间进行堆焊,研究阻焊快速成型材料与堆焊型腔成型率和型腔壁面粗糙度之间的关系。结果表明,采用成型率高和堆焊层质量好的石墨、钨棒导电阻焊材料,可实现非铸造的型腔或平面的堆焊快速成型。使用CO2气体保护焊堆焊成型率达100%。     

双色笔杆注射成型工艺与模具设计

以双色笔杆为例,介绍了双色注射模浇注系统、型腔、型芯与推出系统的设计。从成型工艺参数控制、型芯、型腔设计等方面探讨了提高2种塑料黏合强度的措施。     

组合式高压成型用圆形型腔力学计算探讨

针对在计算组合式高压成型用圆形型腔侧壁厚度时,会出现计算式无意义或计算结果偏大等问题,探讨了组合式圆形型腔侧壁厚度计算的前提条件,并根据实例计算提出了减小型腔壁厚的措施,可为高压成型用圆形型腔的设计及型腔材料的选用提供理论参考。     

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.