铸造湿型砂弹性模量测量及粘弹性的研究

弹性模量是一个与型砂性能密切相关的重要物理参数。基于流变学和型砂微变形理论,用所研制的智能化型砂多项性能测试仪对型砂的弹性模量进行了测量研究。评述了型砂弹性模量的测试方法。试验研究了膨润土含量和紧实率对型砂弹性模量值的影响。并对湿型砂的粘弹性本质进行了分析,认为型砂的粘弹性变形主要是粘土膜开尔文体的弹性变形,型砂弹性模量取决于砂粒间粘土膜开尔文体弹性元件的弹性模量,可以将弹性模量作为型砂性能检测参数之一,用于评定型砂的粘弹性性能。     

Investigation on the viscoelasticity of optical glass in ultraprecision lens molding process

Glass molding press is an efficient manufacturing technology for ultraprecision optical elements with complex shapes. In glass molding, viscoelastic property of glass is an essential aspect that determines the glass deformation behavior around the molding temperature. In this paper, viscoelasticity of glass has been measured experimentally by uniaxially compressing cylindrical glass preforms above the glass transition temperature using an ultraprecision glass molding machine. The elastic modulus and viscosity of glass were obtained by curve fitting techniques using the Burgers model and the Maxwell model for creep and stress relaxation, respectively. Based on the thermo mechanical and viscoelastic parameters obtained from experiments, finite element model simulations of the glass molding process were performed, which can be used to visualize the stress/strain distribution and to predict the residual stress in glass.     

智能化铸造型砂多项性能测试仪的开发研究

在型砂微变形理论研究的基础上,基于8098单片机和高精度传感器技术,开发研制出新型智能化铸造型砂多项性能测试仪,介绍了测试仪的组成结构和测试方法。实测结果表明:智能化测试仪能够检测出反映型砂本质特性的多个型砂性能参数,所测数据误差小,测试精度高。提出用智能化测试仪检测3个新的性能参数来评定型砂的粘弹性性能和粘塑性性能。     

利用硬度计进行弹性模量测试的研究

弹性模量是材料性能的一项重要参数。采用Oliver-Pharr方法计算弹性模量容易受接触深度及初始卸载斜率的影响,尤其是材料呈现堆积状态时。采用量纲分析及有限元仿真,建立材料的弹性模量与压痕参数的解析表达式。数值反演和试验结果表明:提出的方法能获得较高精度的弹性模量,实现了弹性模量的高效测量,降低了试验成本。     

An innovative tester system for measuring mechanical property of foundry molding sand

1 .Introduction Molding sand ProPerties are elosely relevant to castingquality.During molding Proeess,molding sand ProPertiesean direetly affeet the quality of molds ineluding strength,dimension aeeuracy of mold     

用混配土代替煤粉配制型砂

介绍了公司的砂处理设备以及型砂使用混配土前存在的问题。根据热工二部3条新东FCMX-Ⅲ造型线合用一个砂处理系统的情况,对型砂配制材料进行了调整,使用混配土来代替煤粉,并且对紧实率、水分、含泥量等型砂性能参数也进行了调整和优化。生产结果显示:该工艺提高了型砂的综合性能,降低了造型废型率,减少了铸件砂眼、气孔、粘砂等缺陷,不但降低了生产成本,而且免除了煤粉自燃的安全隐患。此外,采用混配土不但经济环保,符合绿色铸造的发展要求,而且粉尘较少,生产条件和工作环境也得到了改善。     

树脂芯砂的混入对湿型砂质量的影响

论述了在用湿型砂生产铸铁件的型砂系统中混入大量树脂砂时,对型砂粒度、膨润土有效含量、抗粘砂性能的影响,并提出了相应的措施.针对铸造一厂的型砂系统,详细介绍了灰铸铁型砂系统物料的变化情况、混入树脂砂对型砂发气量的影响,并成功实施了将灰铸铁型砂系统的旧砂代替新砂使用在球墨铸铁型砂中的工艺,这一工艺的实施不仅降低了成本和铸件缺陷,而且使型砂的性能更稳定.实践证明:在用湿型砂生产有芯铸件时,芯砂的粒度要与型砂的粒度基本一致;混入树脂砂中的树脂膜可以起到一定的防止铸铁件粘砂作用,应当加以利用;适当地往型砂系统中补充旧砂对型砂系统的稳定是有利的;控制好型砂的有效膨润土含量和有效添加剂含量是大量树脂砂混入型砂系统情况下稳定型砂系统的有效途径.     

粘土砂造型线型砂综合添加剂的应用

介绍了膨润土、煤粉、α淀粉、原砂等造型材料的技术要求,分析了紧实率、水分、湿态强度、透气性、型砂粒度等型砂性能对铸件质量的影响情况,提出一种型砂综合添加剂混配方案,并与原砂混配方案进行了生产性试验,结果表明能明显改善型砂性能、提高铸件质量及一次合格率,是改善粘土砂铸造环境和绿色发展的一个较好的措施。     

Constitutive model of micromechanical damage to predict reduction in stiffness of a fatigued SMC composite

Elastic behavior of sheet molding compound (SMC) composites with a given orientational distribution of fibers under cyclic loading is investigated herein. Fatigue tests were carried out over various strain ranges. During each test, evolution of Young’s modulus was measured and the composite was analyzed using scanning electron microscopy. Observations revealed the principal form of degradation to be matrix fiber debonding. A constitutive model that takes into account the reduction of overall elastic properties, i.e., Young’s modulus, was developed. This model uses a Mori-Tanaka mean field approach coupled with a micromechanical damage law. The energetic failure criterion and the failure probability are functions of local shear and normal stresses calculated at each point of the interface of each fiber family. A procedure for identifying the most appropriate material parameters is described in detail. The proposed model agrees well with the experimental results.     

一种用微机计算型砂中粘土分布的方法

本文提出了一种用微机研究型砂中粘土分布规律的方法。指出,粘土覆膜率、粘土膜厚度分布标准偏差及成膜粘土量是评价型砂中粘土分布均匀性的主要定量指标;并首次用微机定量地计算和评价了型砂中粘土分布的规律特性。结果表明,型砂中(?)分布规律和型砂性能具有相对应的关系。     

影响流水线生产粘土型砂性能的因素

稳定地保证粘土型砂质量是大批量粘土砂铸造生产中的关键问题之一。本文从江铃铸造厂某造型生产线上现有的旧砂和型砂性能的测试入手,通过正交实验研究对比分析了型砂组分、残留芯砂含量等各因素对粘土型砂性能的影响,就目前该生产线上铸件的常见缺陷与旧砂和型砂的质量关系进行了讨论,提出了改进型砂质量和减少铸件缺陷的建议。     

自动造型线型砂性能要求及其控制

在自动造型生产线生产过程中,型砂性能对铸件质量具有决定性的影响,型砂性能控制是保证铸件质量的重要工艺手段。合理选择原砂、膨润土、煤粉等原辅材料,控制好型砂的水分、紧实率、透气性、湿压强度、含泥量及有效膨润土含量、挥发份、灼减量和旧砂温度、旧砂水分等是自动造型生产线型砂性能控制的关键。应确定合适的型砂各项性能指标、控制参数和控制方法,严格型砂混制的工艺过程,保证自动造型生产线正常运行,充分发挥自动造型生产线的优越性。稳定了型砂性能,就为获得良好的铸件成品率提供了保障。     

混配土替代煤粉的型砂工艺及在KW线上的生产实践

使用混配土(Additrol)替代煤粉的型砂工艺,结合KW静压造型线铸件生产对型砂性能的实际要求,对型砂配方(如新砂、膨润土的加入量)进行了调整,对型砂性能如紧实率、水分、含泥量等参数进行了调整和优化.经生产验证,该工艺可提高型砂的综合性能,降低造型废型率、铸件废品率,降低了生产成本.     

造型线粉尘回收工艺探讨

含泥量对型砂性能及其稳定性的影响十分重要,型砂中的含泥量是包括有效陶土、有效煤粉、添加剂及型砂中微粒灰分在内的总和。作者通过对造型粉尘的研究,发现回收旧砂中含泥量低至一定质量分数时,可通过粉尘回用稳定型砂含泥量。旧砂处理及混砂除尘过程中抽出的有效膨润土和煤粉,能够回收利用,可以降低成本,同时有利于环境保护。     

静压造型生产线湿型砂质量控制探索

介绍了我厂静压造型生产线湿型砂系统的特点;通过对静压线湿型砂大量实验数据的统计与分析,对湿型砂系统进行了调控,使其达到最优性能。型砂配比,型砂湿混时间,系统旧砂存量,沸腾冷却床冷却水压,除尘系统风量等都是型砂调控的关键点。经过调整的型砂系统,紧实率∶水分稳定在10%～12%,湿压强度稳定在0.16 MPa～0.18 MPa,含泥量控制在11%～12%,有效黏土含量控制在7.5%~8.0%.膨润土及混配土加入量都有所减少,型砂性能不但得到整体提高,产品质量也得到极大改善,而且还节约了成本。     

The influence of composition and processing parameters on the mechanical properties and erosion response of Ni + TiB2 coatings

Sputtered Ni + TiB₂ coatings have been shown to protect Inconel* 718 and Ti-6A1-4V substrates from solid particle erosion. However, before new erosion-resistant coatings can be efficiently designed, it is essential that the role of mechanical properties in determining erosion resistance be fully understood. In this investigation, nanoindentation techniques were used to quantify the effects of substrate preparation, coating composition, and sputtering process parameters on the elastic moduli and indentation hardness of thin coatings deposited on Ti-6A1-4V and Inconel 718 substrates. The influence of these parameters on coating adhesion was determined using a conventional scratch test. Elastic moduli, indentation hardnesses, and coating adhesion were correlated with erosion behavior. The erosion resistance of those coatings that exhibited microscopic ductility is dependent on the nodule diameter and coating properties such as hardness, elastic modulus, and fracture toughness. Inconel 718 is a trademark of The International Nickel Co.     

Characterization of drying behavior of granular materials using magnetoelastic sensors

The aim of the present paper is to show that magnetoelastic sensors can furnish important information about the drying behavior of ceramic materials, and are, therefore, possible alternatives to ultrasonic or cantilever techniques. Sensitive measurements of the resonant frequency of coated amorphous ribbons show characteristic structures at different phases of drying. A model relating the resonant frequency of a magnetoelastic sensor to elastic properties of an applied thin film coating is extended to include the magnetic field dependence of the elastic modulus, the ΔE effect. In this manner, the stress developed during the drying process which contributes to the magnetic anisotropy, can be introduced into the problem. The model is applied to hard clay slurries drying on Metglas 2826MB3 ribbons. The long time value of the sensor resonant frequency is found to be consistent with elastic properties of the clay and the sensor appropriately indicates the appearance of stresses when the meniscus of the drying fluid begins to enter the pores of the solid.     

塑性变形对铝合金弹性模量的影响

回弹是影响弯曲件精度的主要障碍 ,而弹性模量是影响回弹的重要因素之一。一般工程应用中都把弹性模量作为常数 ,而实际上弹性模量随塑性变形的进展在不断发生变化。为了准确把握弹性模量值在塑性变形过程中的变化规律 ,针对应用广泛的铝合金材料 ,采用静力学实验方法 ,对常用的退火LY12及退火LF2 1铝合金的弹性模量在塑性变形中的变化情况进行了实验研究。得到了弹性模量值随塑性变形程度及加载方式变化的规律 ,并分别归纳为数学模型。     

湿型用防粘砂,抗夹砂附加物3R粉的研究

研究了Ｒ１、Ｒ２、Ｒ３的性能及其配制的型砂常温和高温性能，进而优化出由Ｒ１、Ｒ２、Ｒ３组成的３Ｒ粉。由３Ｒ粉和煤粉配制的型砂进行了常温和高温性能的比较。结果表明，３Ｒ粉型砂性能优于煤粉砂性能。３Ｒ粉不但光亮碳生成率高，而且可以提高型砂的热湿拉强度和降低热压应力，延长型砂的爆热起皮时间。３Ｒ粉对膨润土的毒化作用小。经浇注试验表明３Ｒ粉有较好的防粘砂、抗夹砂效果。     

实用型砂组分分析法

介绍了对有效粘土、碳素物、溶凝质、金属分、石英及水分的型砂组分分析方法，并推荐了型砂纯净度的计算方法。