This part is processed with double metals casting that contain boron under the national standard of GB/T150-1993, which makes the cylinder have remarkable advantages of strong hardness, abrasion resistance, oil saving and strong ability of heat dispersing. Bored and grinded with Germany equipment, the cylinder's size accuracy and GD&Tachieve T grades. Besides, the grinding reticulation distributes regularly and it has advantages of equal oil film distribution, fine reciprocating lubrication and quite limited oil consumption.