论文总字数：25148字

摘 要

随着对铸件质量要求日益提高，铸造技术及市场竞争的日益激烈，覆膜砂壳法工艺的应用越来越广泛。目前，酚醛树脂覆膜砂不仅应用于要求高的较简单铸件的铸造生产，而且相当广泛地应用于如汽车、拖拉机的发动机缸体、缸盖等复杂铸件的生产，此外覆膜砂还被广泛的用作阀体的铸造造型材料。但是采用常规的覆膜砂生产复杂的型芯仍然有很多不足之处。本文通过制备和检测覆膜砂及其型砂样品，研究了原砂种类、粒度、粒度配比、预处理，以及偶联剂种类对覆膜砂室温抗拉强度、抗弯强度、灼烧减量的影响。探索提高覆膜砂性能的途径。

研究结果表明，宝珠砂制备的覆膜砂型砂强度高，发气量低。覆膜砂型砂强度随粒径的减小而增大。采用两种三筛砂组成的原砂制备的覆膜砂型砂强度比单一三筛砂大，同时使用三种三筛砂时强度更高。宝珠砂在经过高温焙烧处理后制备的覆膜砂性能下降明显；而宝珠砂在经过酸洗处理后制备的覆膜砂性能得到了显著的提升。宝珠砂经过酸洗处理，其表面活化，产生有利于树脂与砂粒之间粘结的反应的偏酸性基团。改善了粘结剂与砂粒表面的润湿能力,使粘结剂与砂粒的整个表面有良好的接触。择BTSE与邻苯二甲酸二丁酯组合增塑剂增加了覆膜砂的抗拉强度和抗弯强度，同时发气量不会显著增加。

关键词：覆膜砂，原砂，偶联剂，强度，灼烧减量

Abstract

With the increasing demand for quality of castings, casting technology and market competition are increasing fiercely. The process of resin coated sand shell method becomes more widely. At present, the phenolic resin coated sand is not only used for simple casting foundry, and quite widely used in other complex castings production such as cars, tractors and engine block, cylinder head. Moreover, coated sand also been widely used in a molding material body cast. However, using conventional coated sand to product complex cores are still many deficiencies. We through prepare and test resin coated sand, studied the influence on the tensile strenth, bending strength and loss on ignition at room temperaturere of coated sand by raw sand type, particle size, particle size ratio, pre-treatment, as well as on the type of coupling agent.

The results show that resin coated sand prepared by ceramsite has high core sand strength and low gas evolution. With the particle size decreasing, the strength of coated sand increases. The strength of coated sand prepared by two kinds of three sand sieve is higher than which prepared by a single kind. If use three kinds sieve, strength will be higher. The strength of coated sand significantly decreases while use baked sand. But if pickling, performance has been significantly improved. After using pickling treatment on ceramsite, the surface will be actived, and produces acid groups, which is beneficial to the bonding reaction between the resin and sand. It also improves the wetting ability between binder and sand surface, makes them a better contact. Using BTSE and dibutyl phthalate combined plasticizer increased tensile strength and bendign strength of resin coated sands, while gas evolution does not significantly increase.

Key Words: resin coated sands, raw sands, coupling agents, strength, loss on ignition

目 录

摘要 ……………………………………………………………………………………Ⅰ

Abstract …………………………………………………………………………… Ⅱ

1. 绪论 ………………………………………………………………………1

1.1 引言 …………………………………………………………………1

1.2 覆膜砂的研究现状 ………………………………………………………1

1.3 热覆膜法 …………………………………………………………………1

1.4 各项工艺参数对覆膜砂性能的影响 ………………………………………3

1.4.1 原砂的影响 ………………………………………………………3

1.4.2 树脂的影响 ………………………………………………………7

1.4.3 其他添加剂的影响 …………………………………………………8

1.5 本文的研究目的及内容 …………………………………………………12

1. 试验设备及方法 ……………………………………………………………13

2.1 原材料和设备 …………………………………………………………13

2.2 覆膜砂及型砂样品的制备方法 …………………………………………14

2.3 参数测定 …………………………………………………………………15

2.3.1 常温下力学性能测试 ……………………………………………15

2.3.2 灼烧减量测试 ………………………………………………………15

1. 试验结果与分析 ……………………………………………………………16

3.1 原砂对覆膜砂性能的影响 …………………………………………………16

3.1.1 原砂种类及粒度对覆膜砂的影响 …………………………………16

3.1.2 原砂粒度配比对覆膜砂的影响 …………………………………21

3.1.3 原砂预处理对覆膜砂的影响 ………………………………………26

3.2 耦联剂对覆膜砂的影响 …………………………………………………29

第四章 结论 …………………………………………………………………………32致谢 ……………………………………………………………………………………33

参考文献（References） ………………………………………………………………34

第一章 绪 论

1.1 引言

覆膜砂，英文名为Resin Coated Sand，简称RCS，是使用冷法、热法或者干法在硅砂、锆沙、铬铁矿砂等原砂的表面覆上一层酚醛树脂膜的树脂粘结剂砂。在铸造生产中，最初将这种覆膜砂用来制造中空的具有数毫米或十几毫米的壳型或壳芯，因此这种造型制芯方法也被称为壳法。至今，使用覆膜砂能应用于壳型、壳芯的制造，也能制造实体砂芯。

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