Shrinkage cavity and shrinkage porosity, often occurring during the production of heavy v-belt pulley roughcast, may lead to the decrease of the pulley performance and further result in casting rejection. Therefore, it is necessary to study the causes and prevention measures of shrinkage defects of the casting. The material of V-belt pulley roughcast at issue is HT250 and it adopts resin sand casting process. With a large amount of practice in workshop and times of revision of the design of foundry technology, we have found that the shrinkage in the hot spot of heavy v-belt pulley roughcast can be reduced or even eliminated to fully meet the performance requirements with a moderate control of pouring temperature and speed, an optimized design of foundry technology, and a strict limitation of chemical composition. This finding will bring illumination to the production process of other heavy pulley roughcast.
Compositional changes of PM2.5 in NE Spain during 2009–2018: A trend analysis of the chemical composition and source apportionment