The chemical composition is the fundamental quality indicator to steel shot and steel grit,which determines the micro structure and the final result of heat treatment. Germany QUANTRON direct reading spectrograph can test the texture of liquid iron rapidlly and we can do adjustment the correspondingly to guarantee the quality.
The state of steel shot and steel grit microstructure determines the fatigue resistance performance high or low. Nice microstructure makes shot  get higher impact resistant ,which largely extends the working lifetime.