... booster, preload screw precision machining, made of high density ball billet, is widely used in metallurgical, chemical, coal ... of the department should be in the installation of iron removal part of the process from the preparation.4,Binder ... AlloysteelAlloy steelAlloy steelAlloy steelAlloy steelAlloy steelAlloy steelDie-casting StrutureDouble roll single pressureDouble roll single pressureDouble ...