湿型粘土砂有效粘土含量在线快速检测技术的研究

湿型粘土砂有效粘土含量在线快速检测技术的研究＊李大勇曾昕张宇彤（哈尔滨科学技术大学哈尔滨１５００８０）０引言型砂质量是影响铸件质量的重要因素，提高型砂质量控制水平的关键在于发展高效在线检测技术。国内外学者已就型砂质量在线测试系统方面作过大量研究，但其...     

强化湿型砂性能

<正> 迄今为止,国内外铸造工厂大批量生产中、小铁铸件都采用湿粘土型砂造型,但湿型砂使用过程中,如果不严格控制性能,会引起许多铸件废品,例如常见的废品有:砂眼、气孔、夹砂、冲砂、粘砂等。因此,在生产上应用湿型砂时,研究强化湿型砂的性能是个极其重要的课题。湿型砂的最主要性能是强度和透气性。强化性能的途径除了选用优质粘土,控制型砂中的粉尘和死土含量,造型时使具有一定     

国内外造型材料的技术应用现状与发展趋势

本文从绿色铸造和清洁生产工艺及材料要求出发,阐述了铸造造型材料的技术应用现状,概述了粘土砂、树脂砂、水玻璃砂三大造型材料的发展趋势。目前,湿型粘土砂的技术进步,主要集中在粘土型砂的质量稳定控制及其性能快速检测上;树脂砂的技术发展,主要是开发并采用高性能、低毒性、低成本的能够满足铸造工艺要求和提高铸件质量的新型树脂粘结剂;水玻璃砂应是最有可能实现绿色铸造的砂型铸造工艺,该类型砂发展的重点仍然是研发新的工艺方法及材料,彻底解决水玻璃旧砂的溃散性差及回用再生难题。     

粘土砂高压造型型砂控制要点

随着我国铸造产业的国际化，一些国际先进的铸造工艺和铸造不断取代我们传统的手工造型和机械化造型。其中粘土砂高压造型工艺由于其生产效率高，产品适应性强，铸件品质好，非常适合大规模流水线作业。为使型砂很好的适应粘土砂高压造型设备，应有针对性的选择原辅材料，控制型砂性能，选择砂处理工艺。     

快速评价铸造用湿型粘土砂质量的新方法及装置*

介绍快速评价铸造用湿型粘土砂质量的新方法及装置，新方法以型砂有效粘土的质量分数、水的和紧湿率为主要评价指标，采用双电源二次激励法快速测定湿型砂交、直流电导率，通过数学模型求得有效粘土的质量分数及水的质量分数。以上述新方法为基础研制的新装置以８０９８单片机为核心器件，配备制样机构可在线完成自动取样、测试及结果输出。     

型砂质量在线检测与控制模型的研究

型砂质量的在线控制基于两大基本前提：１．实现型砂性能的自动检测；２．寻找并建立型砂成分与性能之间的相互关系，为此，常规试验中既能反映型砂成分变化及适于在线快速检测的紧实率。水分，砂温，透气性与劈裂强度五性能被选作为在线检测项目，文中详细讨论了型砂性能在线检测仪的研制过程，诸项目的检测原理以及仪器所能达到的检测精度，由于采用了８０Ｃ５５２微处理器的控制，本仪器可在１ｍｉｎ内完成全部五项目的检测与结果     

混碾顺序对湿型粘土砂性能影响的探讨

由于粘土湿型砂具有不用烘干设备和燃料,生产周期短,便于组织流水作业,落砂容易、灰尘少、劳动条件好及砂箱寿命长等一系列优点。在各种型砂中,粘土湿型砂仍然是用量最大的,特别是在汽车、拖拉机及内燃机等行业中具有其他型砂无法替代的重要作用。 在各种型砂的混合中,粘土砂的性能波动较大,因为在混制过程中,不仅要将新旧砂、粘土、水分、混入的芯砂及其他附加物混合均匀,而且要揉搓各种     

粘土湿型砂技术讲座：第二讲 粘土湿型砂的组成

二、粘土湿型砂的组成 一般认为,粘土湿型砂是由原砂、膨润土、其他附加材料(如煤粉、淀粉之类)和水组成的。 对于完全用新砂配制的型砂,情况是这样的。但是,在生产条件下,完全用新砂配制粘土湿型砂的情况是极为罕见的,粘土湿型砂的重要特点之一就是反复使用。型砂经造型、浇注、冷却、落砂、磁选、筛分、冷却等复杂的工艺过程之后,再由混砂机混制。每一铸造厂的型砂都在其特定的系统中循环使用。混砂时补加新砂、膨润土、附加物和水,是为了弥补工艺过程中的损耗,以保持系统中的砂量不变。 在反复使用的条件下,由于经受了多次机械作用和热作用,不仅有部分膨润土变成死粘土、部分     

强化湿型砂性能

迄今为止,国内外铸造工厂大批量生产中、小铁铸件都采用湿粘土型砂造型,但湿型砂使用过程中,如果不严格控制性能,会引起许多铸件废品,例如常见的废品有;砂眼、气孔、夹砂、冲砂、粘砂等。因此,在生产上应用湿型砂时,研究强化湿型砂的性能是个极其重要的课题。湿型砂的最主要性能是强度和透气性。强化性能的途径除了选用优质粘土,控制型     

高密度造型型砂的质量控制

介绍高密度造型砂处理系统旧砂的质量要求及含泥量、旧砂温度和水分等方面的控制经验，阐述了通过对型砂性能的检测及分析来保证型砂品质的方法。     

TECHNIQUES ABOUT DIRECT OPTIMIZING CONTROL OF GREEN SAND QUALITY

0 INTRODUCTION*Green sand casting is still one of the main methods used in the world at present and the green sand properties impair the qualities of castings directly. It has been proved that more than 60% of casting defects relate to mold quality and the most important reasons are inadequate sand strength and permeability. In practical production, the molding method does not often change and the mold quality will be affected by green sand properties. In recent years, various techniques …     

湿型砂质量参数智能测试车的研制

针对当前适合中小型铸造厂使用的湿型砂质量参数测试装置短缺的实际状况,在双电源二次激励法的基础上,借助于80C196KC单片机和PC机研制了一种湿型砂质量参数智能测试车,该测试装置可移动工作于生产现场,能够快速检测湿型砂的紧实率、温度、有效粘土质量分数、水质量分数、透气性和综合强度等6个基本参数。试验证明,该测试车具有良好的稳定性和较高的测试精度。     

型砂质量在线检测与控制模型的研究

型砂质量的在线控制基于两大基本前提:1.实现型砂性能的自动检测;2.寻找并建立型砂成分与性能之间的相互关系.为此,常规试验中既能反映型砂成分变化又适于在线快速检测的紧实率、水分、砂温、透气性与壁裂强度五性能被选作为在线检测项目.文中详细讨论了型砂性能在线检测仪的研制过程、诸项目的检测原理以及仪器所能达到的检测精度.由于采用了80C552微处理器的控制,本仪器可在1min内完成全部五项目的检测与结果的打印.以此为基础,本文进一步探讨了利用人工神经网络(ANN)原理建立型砂制备这一非线性系统中成分与性能相互关系的原理与具体实现过程.研究表明,采用由非线性变换单元组成的前馈网络(B一P网络)方法建立的型砂成分与性能关系的网络模型(CPN),可用于型砂的预测,且预测精度高于由传统的回归方法建立的模型,从而为实现型砂质量的在线控制打下了基础.     

超声提取法测定宁夏枸杞中粗多糖的含量

采用超声法提取枸杞中的粗多糖,苯酚-硫酸比色法测定其含量,与传统的水浴回流提取法对比,超声提取法提取枸杞多糖具有得率高、操作时间短、有效成分破坏少及提取结果稳定等特点,具有一定的推广意义。     

黄壤土砂铸型与铸件界面烧结层的力学行为

黄壤土天然粘土砂湿型铸造工艺应用于铸铁生产,能有效预防粘砂缺陷、提高铸件表面质量,同时具有成本低、污染小、效率高的综合优势。这种工艺与普通的湿型铸造工艺相比,最大的区别在于,它会在铸型与铸件之间形成一层致密的烧结壳。这层烧结壳能抵挡住金属液的冲刷和渗透,在金属凝固后能牢固的粘附在铸件表面,可实现高温打箱,而不至于使铸件冷却过快、表面硬度过高,从而提高生产效率;在室温时,它又能轻易地从铸件表面脱落,减轻清砂工作量。为深入了解这一现象,开展对黄壤土天然粘土砂烧结层的高温和室温力学性能的研究,结果表明,烧结层试样在高温下具有很好的塑性,随着温度的降低,塑性减小、抗压强度提高,在室温下表现出明显的脆性。这说明烧结层力学性能的变化与其在铸造过程中的行为正好吻合。     

Comparative measurement of compaction impact of clay stabilized with cement,peat ash and silica sand

This paper concentrates on measuring the compact ability of Taman Wetland clay stabilized with cement, peat ash and silica sand. The organic content of peat makes it a problematic basement soil for highway construction. Such problem can be solved by removing and incinerating the peat for generating peat ash which is applicable for stabilization of the compacted clay. Compaction tests were conducted on both untreated and stabilized clay specimens. The mix designs from the compaction tests were applied on stabilized clay specimens for testing using direct shear apparatus. A feasible mix design can be developed by partially replacing the cement with 1.5% peat ash in the test specimens. Test specimen with the mix design has the highest cohesion of 133 kPa as compared to those of test specimens with other mix designs under study. Such cohesiveness is attributable to the formation of cementation crystals which effectively clogged the pore spaces of the stabilized clay.     

Multi-objective optimization of green sand mould system using evolutionary algorithms

The quality of cast products in green sand moulds is largely influenced by the mould properties, such as green compression strength, permeability, hardness and others, which depend on the input (process) parameters (that is, grain fineness number, percentage of clay, percentage of water and number of strokes). This paper presents multi-objective optimization of green sand mould system using evolutionary algorithms, such as genetic algorithm (GA) and particle swarm optimization (PSO). In this study, non-linear regression equations developed between the control factors (process parameters) and responses like green compression strength, permeability, hardness and bulk density have been considered for optimization utilizing GA and PSO. As the green sand mould system contains four objectives, an attempt is being made to form a single objective, after considering all the four individual objectives, to obtain a compromise solution, which satisfies all the four objectives. The results of this study show a good agreement with the experimental results.     

A novel method to improve Electrical Resistance Tomography measurements on slurries containing clays

Electrical Resistance Tomography (ERT) is a robust and proven technique for slurry flow measurements. The presence of surface-active clays in mineral tailings makes it difficult to make accurate solids concentration measurements using ERT. To evaluate ERT performance under such conditions, measurements on pipeline flows of concentrated clay/water/sand mixtures were performed using ERT. Traversing gamma-ray densitometry and Gamma-Ray Tomography (GRT) systems installed on the pipe loop were used as reference instruments. The results showed that ERT performance is sensitive to clay concentration and is more accurate at lower clay and higher coarse solids (sand) concentrations. A concentration correction model based on a modified Archie's law was developed to compensate for the effect of clay on ERT measurements. The implementation of the correction model was found to significantly improve the accuracy of the ERT measurements on slurries containing clays.     

自硬涂料直接转移法的工艺研究

阐述转移性涂料的制备工艺。采用CO2水玻璃硬化背砂的铸造工艺及在自硬条件下涂料直接转移技术的工艺难点。提出相应的解决办法,并达到铸件生产周期短,成本低。表面光洁,尺寸精度高的目的。     

Thermal testing and diagnostics of the engineering state of flat heaters under real exploitation conditions

A method of on-line thermal testing and diagnostics of the engineering state including estimation of the residual life, of flat heaters under conditions of production and operation has been developed using solution of the inverse ill-posed problem of thermal testing. Recently performed experimental studies of hardware and software have shown the possibility of application of this technique in real field exploitation conditions.