Analysis of hadfield scrap shredder hammer fracture and replacing it with carbide-free nano-bainitic steel

Shredders are widely used in metal scrap recycling. The Shredder device includes hammers joined to a massive rotor. Hammers are responsible for grinding, therefore, play a key role in the shredder. Most of the casted hammers are made from austenitic manganese steel. Austenitic manganese steels usually have good mechanical properties at impact and wear use but in field use as shredder hammer, they are faced to the different type of failures. Finding reasons for these failures could help increasing shredding efficiency and reducing cost. In this study, several factors, such as the lack of work hardening of the as quench hammer, low yield strength and tensile strength, carbide growth at the user's temperature and stopping the work hardening at temperatures between 200 and 300 degrees C have been defined as reasons of failure. Regarding these points, castable Nano bainitic steel suggested as an alternative to the austenitic manganese steels. In file test results proved that nano bainitic steel hammers has better performance than austenitic manganese steel hammers.