1 .Be  made of low carbon steel

2. Heat treatment, quenched and tempered 

3  Developed a new technology as well to shape  After its surface is carburized, both toughness of core and hardness of surface are improved. Besides, at the same weight, it is two times as strong as original quenched and tempered parts that made of medium carbon steel, so it improves its reliability and meets the needs of further consolidation and reduction of weight in modern I.C. Engine.