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一、铸造用树脂简况目前国内所采用的热芯盒制芯粘结剂,绝大多数属呋喃型树脂,它们是由尿素、甲醛、糠醇按一定克分子比合成。我厂选用的是呋喃Ⅰ型树脂,它属糠醇改性尿醛树脂,该树脂混制的芯砂特点是:固化速度快、常温强度高、热态强度也较好。其不足之处是含氮量高达13.5％、芯子吸湿性大、发气量大、易使铸件产生气孔、尤其是球铁件易产生皮下气孔,我厂投产以来球铁件的气孔及皮下气孔废品约占综合废品率的13-21％。无氮树脂是呋喃系列中的一种、也被称做呋喃Ⅱ型树脂、其主要成份是糠醇,另加少量甲醛苯酚合成、其最大特点是无氮。在国外铸造生产中砂芯粘结剂一般都采用低氮或中氮树脂,而球铁生产都采用无氮树
First, casting resin profile At present, the hot core box core binder used in the country, the vast majority of furan resin, which is urea, formaldehyde, furfuryl alcohol by a certain molar ratio of synthesis. I plant is selected furan type Ⅰ resin, which is furfuryl alcohol-modified urea-formaldehyde resin, the resin mixed sand core features are: fast curing, high strength at room temperature, hot strength is also better. The disadvantage is that the nitrogen content of up to 13.5%, the core moisture absorption, large gas, easy to make castings produce pores, especially ductile iron parts easy to produce subcutaneous stomachache, since the plant put into operation the ductile iron pores and subcutaneous pores Waste products account for about 13-21% of the total reject rate. Nitrogen-free resin is a series of furans, also known as furan Ⅱ type resin, the main ingredient is furfuryl alcohol, plus a small amount of formaldehyde phenol synthesis, the most prominent feature is the non-nitrogen. In the foreign foundry core binders are generally used in the production of low nitrogen or medium nitrogen resin, ductile iron production and use of nitrogen-free trees