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球墨铸铁易产生缩松、缩孔缺陷,过去沿用铸钢工艺,靠加大冒口来进行补缩,结果不但使铸件收得率大大降低,而且还很难完全消除缩孔、缩松缺陷。我厂根据球铁凝固特性,通过生产实践,掌握了冒口和冷铁相结合的造型工艺,提高了球铁件的质量和铸件收得率。一、使用冷铁目的1.由于冷铁的激冷作用,可以调整铸件各部位的冷却速度,使易产生缩松、缩孔的热节处加快冷却,从而消除缩孔、缩松缺陷,得到致密的优质铸件,并可用小冒口或无冒口铸造。2.大断面球铁的冷却凝固时间较长,由于孕育衰退造成球墨畸变产生球化不良、用冷铁后,加
Nodular cast iron easy to produce shrinkage, shrinkage defects, the past use of steel casting process, by increasing the feeder to carry out shrinking, the result will not only greatly reduce the casting yield, but also difficult to completely eliminate shrinkage, shrinkage defects. According to the solidification property of the ductile iron, our factory mastered the molding process combined with the riser and the chill iron through the production practice, and improved the quality of the ductile iron piece and the yield of castings. First, the purpose of the use of cold iron 1. As the chill iron role, you can adjust the casting parts of the cooling rate, so easy to produce shrinkage, shrinkage of the hot section to speed up cooling, thereby eliminating shrinkage, shrinkage defects, get Dense, high-quality castings, available in small or non-riser castings. 2 large section ductile iron cooling solidification time is longer, due to pregnancy decline caused by ductile aberration caused by poor nodularity, with chilled iron, plus