酮醛改性呋喃树脂砂制备工艺研究

介绍了一种新型酮醛改性呋喃树脂制备工艺,通过对呋喃树脂砂抗拉强度的测定、呋喃树脂游离甲醛含量的测定以及多元醇B剂替代试验,分析了丙酮与甲醛摩尔比、碱性反应时间以及酸性反应时间对改性呋喃树脂砂强度的影响.结果 显示:(1)当丙酮与甲醛摩尔比为1∶1.25,碱性反应温度为80℃,碱性反应时间为2h,碱性反应pH值为9.5,...     

固化剂自控仪在自硬砂造型线上的运用

简述了呋喃树脂A+B固化剂自动控制仪的工作原理和结构特点,介绍了该固化自控仪在酸硬化呋喃树脂砂造型线上成功运用的工艺要素和注意事项,并发现砂温与A,B泵的频率以及固化剂的平均总酸度的关系.在酸硬化呋喃树脂砂造型线上配置圣泉公司的固化剂自控仪,再生砂的树脂加入量为O.65%～O.85%(BOS),A+B固化剂加入量为30%～40%(BOR),解决了自硬砂生产中的再生砂的砂温对固化速度的影响,保证了铸型和砂芯的质量,降低了生产成本.     

大型铸钢件用改性呋喃树脂砂的研究

在常规呋喃树脂合成工艺基础上,通过加入多酚类有机物改性,开发出一种适用于大型铸钢件造型、制芯用的呋喃树脂粘结剂.其主要特点是:有毒气体释放量小(游离甲醛含量≤0.1%),型芯砂粘结强度高(≥1.6MPa),浇注后退让性好.为了降低固化剂中的含硫量和延长型芯砂可使用时间,对普通磺酸固化剂的成分进行了调整,新固化剂中含硫量比普通固化剂降低20%-50%,而树脂砂的可使用时间可延长到60min.介绍了树脂和固化剂在大型铸钢件上成功应用的情况.     

聚氨酯砂改性工艺研究

采用红外光谱技术研究了聚氨酯砂的固化反应机理, 通过向聚氨酯砂中加入呋喃树脂砂进行改性处理, 并采用热失重及扫描电子显微分析技术研究了聚氨酯砂的改性机理。结果表明, 聚氨酯砂中加入呋喃树脂砂以后, 由于在高温下树脂膜分解速度下降, 高温强度得到提高。呋喃树脂砂合适加入量为１０ ％ , 改性聚氨酯砂具有良好的综合性能     

原砂粒度、树脂加入量对呋喃树脂砂强度的影响

树脂砂强度直接影响到铸件品质。树脂砂强度受到多种因素影响,其中,原砂粒度、树脂加入量对呋喃树脂砂的强度有着非常强烈的影响。通过对不同树脂固化剂加入量以及不同原砂粒度的试样强度进行分析,同时利用扫描电镜分析树脂砂粘结、断裂机理,研究了上述因素对呋喃树脂砂强度的影响。结果表明,粘结桥间的气孔将直接影响到树脂砂强度,树脂添加量在1.25%~1.75%时,树脂砂强度较好。原砂粒度较小时,粘结桥容易与原砂发生剥离,降低树脂砂强度。     

Substitute materials of furfuryl alcohol in furan resin used for foundry and their technical properties

Based on a special synthesis process of furan resin, the furfuryl alcohol (FA), the main component of typical no-bake furan resins is substituted by ethanol and xylitol mother liquor which is relatively low price and chemically active Through orthogonal test, the optimal amount of xylitol liquor, ethanol and modifier has been determined Finally, the test results on technical properties show that the performance can meet the production requirement well, which indicate a success in this substituting attempt.     

高退让性呋喃树脂砂对铸钢件热裂纹的有效防止

在呋喃树脂合成过程中引入柔性基团并添加高温增塑剂，用热变形量测试仪分析了树脂砂的高温性能。结果表明：研制的高退让性呋喃树脂能明显降低型芯热膨胀，延长高温塑性时间，改善型芯退让性，有效防止铸钢件热裂纹的产生。     

Curing mechanism of furan resin modified with different agents and their thermal strength

The curing mechanism of furfuryl alcohol and urea-formaldehyde furan resins was investigated using infrared spectroscopy (IR) technique. The curing productions of urea-formaldehyde furan resins modified with different agents (i.e. sorbitol, polyester poiyol, phenol and acetone) and the productions of incomplete curing were characterized by differential thermal analysis (DTA) and thermal gravity analysis (TG). The results indicate that except for polyester polyol, the other modifiers have little effect on the thermal strength of urea-formaldehyde furan resin. Furthermore, the thermal strength can be improved at a temperature of higher than 550℃.     

新型酯硬化水玻璃砂在铁路车辆铸钢件生产中的应用

介绍了新型酯硬化水玻璃砂造型制芯生产线以及所用原材料、型芯砂配方和工艺性能,分析了影响酯硬化水玻璃砂性能的因素,并且对新型水玻璃酯硬化自硬砂和呋喃树脂自硬砂进行了经济效益对比分析.     

Effect of gel time of 3D sand printing binder system on quality of sand mold/core

Two important factors affecting the performance of sand mold/core generated by 3D printing (3DP) are strength and dimensional accuracy,which are not only closely related to the reactivity of furan resin and the phase transition of silica sand,but also the curing agent system of furan resin.This paper studies the influence of gel time on the strength and dimensional accuracy of a 3DP sand mold/core,taking the furan resin system as an example and using a sand specimen generated by a 3DP inkjet molding machine.The experiment demonstrates that the gel time of 3 to 6 min for the sand mixture suits 3DP core-making most under the experimental condition.However,it should be noted that under the same resin condition,the strength of a no-bake sand mold/core is higher than that of a 3DP sand mold/core.The dimensional accuracy of the sand mold/core does not change significantly when the gel time is less than 15 min.Improving the activity of binder and developing ultra-strong acid with low corrosion shall be an effective way to improve the quality of the mold/core by 3D printing.     

树脂品质对铸件综合成本的影响

为降低灰铁铸件的生产成本,选择了两种呋喃树脂进行对比试验,分析了造型材料的性能指标,测试了工艺试样的抗拉强度,并进行了生产现场验证.结果表明,混制的型砂达到相同强度,使用价格稍高但加入量少的树脂,铸件的综合成本反而低;树脂加入量少还可以改善劳动环境,降低砂子再生的难度,减轻氮气孔产生的倾向.     

环保型无氮自硬呋喃树脂砂粘结剂的制作应用

介绍了基本上不含游离甲醛及游离苯酚含量很低的无氮自硬呋喃树脂砂粘结剂的制作方法和应用。这种粘结剂仍然使用甲醛、糠醇(呋喃甲醇)、苯酚等原料作为其合成树脂的主要材料,使用一种低分子物作为合成改性剂,采用适当的工艺制作而成,不改变树脂的性能,且树脂制作成本基本不变。该粘结剂的使用可在很大程度上降低铸件生产过程的游离甲醛和游离苯酚对生产环境和操作人员的污染和损害。     

多元醇改性呋喃树脂合成工艺研究

在现有脲醛呋喃树脂合成工艺基础上,选用山梨醉和芳烃聚醋多元醉两种多羟基化合物改性呋喃树脂,研究其添加量与添加位置对树脂砂强度影响,得出两种多元醇改性吠喃树脂最佳工艺条件,并通过红外光谱对它们改性过程的反应机理进行研究,从而得出它们的改性反应机理.并从反应机理上解释它们改性效果上差异.     

面向工业设计的塑料表面铝涂层的结合强度

目的采用电弧喷涂方法在环氧树脂和ABS塑料表面喷涂铝涂层,研究涂层结合强度的影响因素。方法第一组试验是塑料表面喷砂后,喷涂铝涂层;第二组是塑料表面喷砂后,涂覆一层高强度环氧树脂结构胶,再喷涂铝涂层。选择喷涂气体压力、喷涂电流和喷涂距离三因素进行正交试验,采用粘结拉伸法测试结合强度,并用照相法测量铝液和环氧树脂塑料、Q235钢的接触角。结果本试验条件下,二种塑料电弧喷涂铝涂层结合强度的影响因素主次顺序为:空气压力喷涂电流喷涂距离。最优方案是:喷涂气体压力为0.7 MPa,喷涂电流为220 A,喷涂距离为160 mm。未涂覆高强度环氧树脂结构胶的涂层,结合强度最大不超过3 MPa;涂覆高强度环氧树脂结构胶的涂层,结合强度达到近20 MPa。铝液和Q235钢的接触角是45°,和环氧树脂塑料的接触角是135°。结论环氧树脂和ABS塑料表面电弧喷涂铝涂层的结合强度低的主要原因是铝液和它们之间的润湿性差。涂覆高强度环氧树脂结构胶后,喷涂工艺参数对涂层的结合强度影响不明显,结合强度受控于环氧树脂结构胶的粘接作用,使涂层的结合强度显著提高。     

商用车底盘铸件的发展对铸造材料的新要求

随着底盘铸件在材料性能、外观质量、内部质量、铸件结构等方面要求的提高,铸造企业对铸造材料、成分控制、材料性能等方面也提出了更高的要求,其中包括:控制生铁和废钢中的微量元素含量;根据铸件情况及生产条件调整球化剂、蠕化剂和孕育剂的成分和粒度;提高炉衬和包衬材料抗冲刷的能力,延长其使用寿命,等等。覆膜砂取代呋喃树脂砂是发展趋势,随着铸件内部和表面质量要求的提高,铁液净化剂、密封软垫、通气针堵头等一些特殊用途的材料的需求量在逐步增加。     

铸造用呋喃树脂新型增强剂的研究与应用

介绍了新型硅烷偶联剂对铸造用呋喃树脂的增强效果,研究了生产工艺、外界环境对增强剂的影响,探索了新型硅烷偶联剂的有效期等性能,并对其增强原理进行了初步讨论.     

CO2固化碱性酚醛树脂的制备及固化机理研究

铸造用CO2固化碱性酚醛树脂是一种新型造型、制芯用粘结剂,它是由羟甲基含量较高的甲阶碱性酚醛树脂和含氧酸盐及碱等物质组成的混合物,甲阶碱性酚醛树脂性能及它们的组成是影响CO2固化碱性酚醛树脂砂强度的主要因素。模仿实际CO2固化酚醛树脂砂的固化过程,利用测定不同条件下碱性酚醛树脂水溶液pH值变化的方法,对CO2固化碱性酚醛树脂与不同交联剂的固化机理进行了探讨,从中得出有关CO2固化碱性酚醛树脂的交联剂和碱的用量范围,并在此基础上,考察它们和表面稳定剂对砂型抗压强度的影响,获得铸造用CO2固化碱性酚醛树脂较佳组成。     

呋喃脲醛树脂结构组成的分析和推断

从呋喃树脂合成过程的特点出发，结合波谱分析，对呋喃脲醛树脂中糠醇的聚合态、糠醇与脲醛的缩合方式以及树脂的主要链节结构组成进行了分析和推断。     

Development of a new instrument for measurement of high temperature mechanical properties of resin-bonded sand

The mechanical properties of resin-bonded sand mixtures at high temperatures significantly affect the quality of casting. However, the existing instruments for high-temperature performances testing mainly focus on inorganic binder-bonded sands no matter the test items or the atmospheric protection, while the instrumentss specially designed for resin-bonded sand are not yet available. A new instrument for testing the hightemperature performance of resin sand was designed including the confirmation of the testing parameters, loading, measurement and control systems, and the design of the frame shape and heating furnace. This instrument can test the compressive strength, heat tolerance time and restraining load of phenol-formaldehyde resin coated sand, self-hardened furan resin sand, and trimethylamine(TEA)-based resin bonded sand at high temperatures. The developed instrument has a high accuracy offering smaller than 0.3% deviation at a full scale in the measurement of the high temperature compressive strength and the restraining load over the range of 0-6.8 MPa and 0-2,000 N, respectively. The high temperature heat tolerance time range is 0-300 s and its measurement accuracy is ±1 s.     

Optimization of tensile strength for new type acetone-urea-formaldehyde furan resin using uniform design

In this study,the 24 h tensile strength of new type acetone-urea-formaldehyde furan resin (nitrogen content 3%) was investigated by uniform design optimization.Four independent variables such as acetone:formaldehyde molar ratio (mol/mol),solution pH value,reaction temperature (℃) and reaction time (min) were considered in the experiments.U13(134) uniform design was employed and the equation of 24 h tensile strength model was obtained after 13 experimentations.The 24 h tensile strength was optimized by apply...