防渗硫涂料在呋喃树脂自硬砂铸钢件生产中的应用研究

硫是导致铸钢件产生热裂的主要因素之一。根据呋喃树脂自硬砂在浇注铸钢件时热分解而形成的SO2 气体向液态金属扩散机理 ,研究试验了九种不同成分的锆基涂料对铸钢件表面防渗硫的效果。试验表明 ,烧结型涂料的防渗硫效果明显优于反应型涂料 ,而烧结 反应复合型涂料的效果最好     

砂型铸造涂料研究与应用的几个新进展

介绍了砂型铸钢用烧结剥离型防气孔和防增碳涂料、新型浅色烧结剥离型铸铁涂料、粘土湿型砂铸造醇基喷涂涂料、代替锆英粉涂料生产中大型碳钢和合金钢铸件的铬铁矿粉涂料、防止铸件脉纹缺陷的激冷涂料和绝热涂料、高压无气喷涂机等的性能特点及应用实例,简要探讨了国内砂型铸造涂料领域的发展方向.     

防止磺酸自硬树脂砂引起球铁件表层异常组织涂料的研制

采用甲苯磺酸作催化剂的呋喃树脂自硬砂生产稀土镁球铁件,通常会在铸件表层出现片状石墨异常组织,显著降低冲击值.研究发现,使用碳酸钙、赤泥、还原性钢渣等碱性无机化合物涂料和采用含有长石粉、滑石粉的烧结型涂料时,能吸收和阻止对甲苯磺酸受热分解析出的含硫气体侵入铸件表层,有助于消除球铁件界面硫的富集,防止铸件表面形成异常组织.     

关于铸造涂料易剥离粘砂层理论的探讨

型砂和涂料在浇注温度下生成一些低熔物,能促使耐火基料烧结并粘着在铸件表面上.但粘砂层可区分为难剥离粘砂层和易剥离粘砂层两种,生成氧化物隔离层、光亮碳;碳隔离层和珐琅态烧结层时,铸件冷却之际会自动剥落下来.因此,研制涂料配方要依循“一要烧结、二要剥离”的烧结剥离型涂料的原则.本文还扼要讨论了促使涂料层烧结和剥离的各项措施,以及强化烧注气氛工艺”.     

一种新型防渗碳涂料

防渗碳涂料在低温时固相烧结的收缩性 ,阻渗材料的转化温度 ,在工艺温度下涂层的致密性 ,以及涂层组分的化学稳定性、粘度和表面张力是该涂料是否防渗的关键。目前国内热处理行业所使用的防渗涂料多采用生料配制而成[1,2 ] ,这些防渗涂料不同程度地存在上述几方面的问题 ,因而在使用中常常出现漏渗。本文作者研制出一种硅酸盐型的防渗材料 ,其中用熔块釉 (熟料 )作阻渗材料 ,已成功应用于生产实践。1　试验材料及方法　　本防渗碳涂料有以下部分组成 :(1 )阻渗材料 :亦称熔质料 ,它是保护涂层的主要组成部分。本试验选用了一种固液相转化温…     

易剥离粘砂层理论在铸铜涂料中的实践

大型推进器铸件铸型涂料是为实现烧结剥离型涂料系列化和引进技术国产化而研制的新型涂料,具有较高的理论和实用意义。本涂料使用与金属氧化物(氧化铜、氧化锡等)不起反应的碱性耐火材料作基材,有助于氧化物隔离层的沉积,具有良好的剥离性;调节硅铝酸盐的组成使它迫近最低共熔点,并添加适宜的助熔剂;本涂料使用无机膨润土代替有机膨润土作醇基涂料的稠化剂,具有悬浮性好,不用苯作活化剂,点燃黑烟少等优良性质。浇注后,烧结的涂层能自动从铸件上剥离下来,铸造缺陷少,清理方便。     

气体渗氮件的阻渗

概述了气体渗氮件局部阻渗的必要性,对阻渗涂料的要求及阻渗效果的检测方法,介绍了一种配制方便、价格低廉、防渗效果良好的SG-Ⅱ型防渗氮涂料。     

大型铜合金铸件铸型涂料的研究

大型铜合金铸件铸型涂料是为实现烧结剥离型铸型涂料系列化和引进技术国产化而研制的新型涂料,具有较高的理论和实用意义。本涂料使用与金属氧化物(氧化铜、氧化锡等)不起反应的碱性耐火材料作基材,有助于氧化物隔离层的沉积,具有良好的剥离性;调节硅铝酸盐的组成,使它迫近最低共熔物,并添加适宜的助熔剂;本涂料使用无机膨润土代替有机膨润土作醇基涂料的稠化剂,具有悬浊性好,不用苯作活化剂,点燃黑烟少等优良性质。浇注后,烧结的涂层能自动从铸件上剥落下来,铸造缺陷少,清理方便。     

烧结溃散型铸铁涂料的试验

用正交试验优选出以高铝粉、长石粉为基料的烧结溃散型涂料,其抗粘砂效果良好.     

一种镁砂粉与刚玉粉复合烧结铸型涂料的研制

采用镁砂粉和刚玉粉作为耐火骨料制备了一种烧结型铸型涂料,实验研究了两种骨料的适宜配比,分析了骨料组元比例对烧结过程的影响;优化设计了一种以镁砂粉和刚玉粉为复合耐火骨料的铸型涂料配比,检测了涂料的性能。结果表明:复合骨料烧结后的涂层产生了镁铝尖晶石(Mg Al_2O_4),当镁砂粉和刚玉粉混合质量为7∶3时,涂层中的Al_2O_3全部参与烧结反应;硅溶胶(SiO_2·n H_2O)的加入可以改善涂层的高温强度,防止出现暴热裂纹;优化后的涂料具有较好的综合性能,能有效地防止不锈钢铸件表面出现粘砂现象。     

The application of thermal sprayed coatings for pig iron ingot molds

Molds made of gray cast iron for casting pig iron ingots are subjected to severe temperature fluctuations. The main life- limiting factor for mold damage is the formation of surface cracks arising from thermal fa-tigue. Various flame and plasma sprayed coatings were investigated to extend the life of these molds. Coating materials studied include plasma sprayed ceramic coatings with bond coats as well as flame sprayed oxidation- resistant alloy powders. The results of cyclic furnace tests from room temperature to 1100 °C in air, simulating the thermal cycle in casting, indicated that failure occurred along the interface between the bond coat and the gray iron substrate because of iron oxidation, and not at the interface between the ceramic top coat-ing and the bond coating for a superalloy substrate. The field test results indicated that plasma sprayed alumina coatings with 200 μm top coating thickness are the most promising materials for pig iron casting.     

原位反应法制备的碳化硅涂层/三维编织碳纤维的氧化性能研究

采用原位反应法在三维编织碳纤维(原纤维)表面制得β-SiC涂层,通过XRD,SEM,等温氧化失重和非等温热重分析等测试手段研究了制备方法对涂层性能的影响.结果表明:利用此法可得到均匀、完整,界面结合良好的涂层,涂层厚度增加,涂层/三维编织碳纤维(复合纤维)抗氧化性能增强.并对复合纤维氧化反应的机理进行了研究.     

Soldering mechanisms in materials and coatings for aluminum die casting

The stability against reaction with aluminum of materials and coatings commonly used in aluminum die casting was investigated. The materials considered here were H13 tool steel and Anviloy® 1150, whereas the coatings were TiN and CrN. Special model, freestanding, multilayered thin film structures were used in this study, in association with complementary differential scanning calorimetry and X-ray diffraction. The nature of the reactions (endo or exothermic) and their onset temperatures up to 1273 K were determined. Based on of these results, some activation energies for the different reactions taking place between aluminum and die material or between aluminum and coatings could be established. Different intermetallic compounds were formed in these reactions, which were identified by post mortem X-ray diffraction analysis. Anviloy® 1150 showed superior stability as compared to H13 tool steel, whereas CrN was more inert than TiN coatings. CrN exhibited the best performance among all materials and coatings considered here, although its practical application relies also on adhesion of the CrN coating to the die bulk material. The results are discussed on the lights of two recent models for soldering in aluminum die casting.     

V法铸造涂料在耐磨铸件上的应用

针对V法铸造工艺的特殊性,分析了V法铸造涂料快干性、粘附性、致密性、透气性和涂挂性的影响因素,介绍了涂料性能的测试方法.将研制的V法铸造涂料用于高锰钢铸件,试用结果表明,涂料具有较快的干燥速度、与薄膜较好的粘附性、合理的透气性和致密性及良好的涂挂性,可满足V法铸造耐磨铸件的工艺要求,有效提高耐磨铸件的质量.     

钼电极玻璃基防氧化涂层预烧工艺研究

采用料浆涂覆的方法在钼基体表面制备了玻璃基防氧化涂层;通过SEM、XRD、防氧化性能测试对涂层表面形貌、显微组织结构和氧化失重进行了研究;探讨了玻璃基涂层预烧工艺对钼电极表面的防氧化性能的影响.结果表明:涂层经1100℃保温10min的热处理后,具有最优的防氧化性能.     

等离子弧堆焊TiB2-金属陶瓷涂层的组织及性能

采用等离子弧堆焊设备，通过钛合金和硼合金粉末之间的高温冶金反应，在堆焊过程中原位合成了TiB2，在普通碳钢表面制备了含TiB2的金属陶瓷层。并对堆焊层进行了显微组织、X射线衍射分析、硬度及抗裂性能试验。试验结果表明，这种一步性原位合成工艺所获得的堆焊层主要由针状TiB2晶须与Fe及其硼、碳化合物组成，陶瓷层与基体间实现了冶金结合；堆焊层抗裂性能优于不含TiB2的铁基B4C堆焊层。     

New sol-gel refractory coatings on chemically-bonded sand cores for foundry applications to improve casting surface quality

Foundry refractory coatings protect bonded sand cores and moulds from producing defective castings during the casting process by providing a barrier between the core and the liquid metal. In this study, new sol-gel refractory coating on phenolic urethane cold box (PUCB) core was examined. The coating density, viscosity, moisture content and wet and dry weight of the coating were evaluated on cores that had been coated at three different dip-coating times. The coating coverage, surface appearance and depth of penetration into the cores were examined with a Stereomicroscope. Gray iron castings were produced with sol-gel coated and uncoated cores and the results were related to the coating properties. The casting results were also compared with castings made with cores coated with commercial alcohol-based and water-based foundry coatings. The analyses show that castings produced with sol-gel coated cores have better surface quality than those from uncoated cores and comparable surface quality with the commercial coatings. Therefore, the new sol-gel coating has a potential application in the foundry industry for improving the surface finish of castings thereby reducing the cost of fettling in the foundry industry since the raw materials and technology are easily affordable.     

消失模铸造用涂料

介绍了对消失模铸造用涂料的技术要求,包括透气性、强度、润湿性、粘着性、干燥速度等和水基涂料、醇基涂料、树脂涂料的特点及耐火材料、粘结剂、溶剂、添加剂等主要组成的作用与选配原则;同时介绍了常用的涂料配方,常用涂料搅拌机的参数与性能特点、涂料的主要性能测试方法和涂料的干燥工艺等。     

硫对消失模铸造灰铸铁组织和性能的影响

在消失模铸造条件下,通过向铁液中加入硫铁增硫的方法改变铸铁的含硫量,研究了含硫量的变化(0.0270%～0.143%)对灰铸铁微观组织和力学性能的影响.结果表明:当含硫量小于0.121%时,薄壁灰铸铁中过冷石墨的数量随着硫量的增加而减少,当含硫量增至0.143%时,过冷石墨基本消除;在试验成分范围内,随着含硫量的增加,灰铸铁的抗拉强度及硬度先提高后降低,当硫含量在0.078%～0.121%范围时,灰铸铁的微观组织和力学性能最为理想.     

铸造涂料在灰铸铁缸体上的选配及应用

从组芯工艺和砂芯复杂程度、铸件缺陷、芯砂类别及粒度方面介绍了铸造涂料的研配及选型,详细阐述了铸造涂料在不同系列轿车发动机缸体砂芯上的应用情况.最后指出:涂料的选择应根据不同铸件和砂芯的质量要求,选用适合铸件或砂芯特点的专用涂料,使涂料的性能与铸件质量相得益彰,既不使涂料性能过度优异造成成本浪费,又能满足铸件质量需求;供...