尼龙纤维含量和长度对精铸硅溶胶型壳性能的影响

发布时间：2018-03-02 17:22

本文选题：熔模精铸　切入点：尼龙纤维　出处：《南昌航空大学》2017年硕士论文　论文类型：学位论文

【摘要】：熔模精密铸造技术是航空航天高精度复杂结构零部件成形的主要方法之一。传统熔模精铸制壳周期长,涂层浆料干燥慢;型壳湿强度较低,搬运过程中易破损;型壳残留强度偏高,脱壳性差;型壳透气性较差,影响铸件质量,且强度和透气性存在相互制约的关系。通过加入尼龙纤维增强型壳,研究纤维含量和长度对硅溶胶浆料及型壳性能的影响,为型壳制备提供理论指导。本文采用尼龙纤维增强硅溶胶型壳,尼龙纤维加入到硅溶胶浆料中,通过搅拌作用对硅溶胶浆料中的尼龙纤维进行分散,研究尼龙纤维含量和长度对硅溶胶浆料及型壳性能的影响规律,分析尼龙纤维对硅溶胶型壳的增强机制,优化尼龙纤维增强硅溶胶型壳的焙烧工艺。实验结果表明,搅拌作用可有效地改善尼龙纤维在浆料中的分散性,当搅拌转速为210n/min时,纤维分散较为均匀;当纤维含量在0%~0.75%,纤维长度在2mm~6mm时,随着纤维含量和长度的增加,浆料运动粘度逐渐增大,型壳挂浆质量与各方向的涂挂厚度也逐渐增大;随着纤维含量和长度的增加,型壳的常温抗弯强度呈先增大后减小,焙烧后抗弯强度呈先增大后减小再增大,焙烧后透气率呈先增大后减小;当纤维含量为0.60%时,型壳常温抗弯强度为最大值3.06MPa,纤维长度为4mm时,型壳常温抗弯强度为最大值2.92MPa;当纤维含量为0.45%时,型壳焙烧后抗弯强度为最小值3.96MPa,纤维长度为5mm时,型壳焙烧后抗弯强度为最小值4.03MPa;当纤维含量为0.60%时,型壳透气率为最大值3.25,纤维长度为5mm时,型壳透气率为最大值3.42。通过搅拌作用对硅溶胶浆料中的尼龙纤维进行分散,以及尼龙纤维含量和长度对硅溶胶浆料及其型壳性能影响的研究,当纤维长度在4mm~5mm,纤维含量在0.45%~0.60%时,型壳的抗弯强度和透气性综合性能较好,为高质量复杂铸件的生产提供理论和技术指导。
[Abstract]:Investment casting technology is one of the main forming methods for aerospace parts with high precision and complex structure. Traditional investment casting has long shell making period, slow drying of coating slurry, low wet strength of mold shell and easy breakage during handling. The residual strength of mould shell is high and the exfoliation property is poor, the air permeability of mould shell is poor, and the quality of casting is affected, and the relationship between strength and permeability is restricted. The effects of fiber content and length on the properties of silica sol slurry and shell were studied in order to provide theoretical guidance for the preparation of mold shell. In this paper, nylon fiber was used to reinforce silica sol shell, nylon fiber was added to silica sol slurry, and nylon fiber was added to silica sol slurry. The effects of nylon fiber content and length on properties of silica sol size and shell were studied by agitation, and the reinforcing mechanism of nylon fiber on silica sol shell was analyzed. The roasting process of nylon fiber reinforced silica sol shell was optimized. The experimental results showed that the dispersion of nylon fiber in the slurry could be effectively improved by stirring. When the stirring speed was 210 n/ min, the dispersion of nylon fiber was more uniform. When the fiber content is 0.75 and the fiber length is 2mm or 6mm, with the increase of fiber content and length, the kinematic viscosity of the slurry increases gradually, and the quality and the coating thickness of the mould shell slurry increase gradually, and with the increase of fiber content and length, The bending strength of the shell at room temperature increased first and then decreased, the bending strength increased first and then decreased after calcination, the air permeability increased first and then decreased after calcination, and when the fiber content was 0.60%, The maximum bending strength at room temperature is 3.06MPa, and the maximum value is 2.92MPa when the fiber length is 4mm, when the fiber content is 0.45, the flexural strength is 3.96MPa, and the fiber length is 5mm, when the fiber content is 0.45, the bending strength of the shell is 3.96MPa, the fiber length is 5mm, the bending strength of the shell is 3.96MPa, and the fiber length is 5mm. When the fiber content is 0.60, the maximum air permeability of the shell is 3.25, and the air permeability of the shell is 3.42. The nylon fiber in the silica sol slurry is dispersed by stirring. The effect of nylon fiber content and length on the properties of silica sol paste and its shell is also studied. When the fiber length is 4 mm or 5 mm and the fiber content is 0.45 ~ 0.60, the bending strength and air permeability of the shell are better. To provide theoretical and technical guidance for the production of high quality complex castings.
【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG249.5

【参考文献】