Production of grey cast iron powder via target jet milling

Target jet milling was used for the first time to convert cast iron scraps to powder. An experimental apparatus was designed which comprised a compressor, a mixing section, a nozzle, an impact chamber and two suction machines. Milling parameters i.e. the target to nozzle distance, the feed rate and the impact angle were optimized through appropriate tests. The travel distance of 8 cm and the impact angle of 90° were found to be ideal parameters of milling. The effect of feed rate on production of powders greater than 45 μm was found to be opposite to the production of the fines (< 45 μm). Investigation of the fragmentation procedure of particles revealed that, the existence of graphite flakes in cast iron matrix plays the most important role in particle breakage.