在现有二辊斜轧穿孔过程中,一般用气缸推入装置将管坯推入穿孔机。当管坯与轧辊接触后,推入装置便返回原始位置,管坯在轧辊中进一步前进则靠轧辊与管坯之间的摩擦来实现。应该指出,为保证穿孔过程顺利进行,这种推入方式的穿孔机必须具有克服顶头轴向阻力所需的顶头前压下量。众所周知,在穿孔时,顶头前压下量若超过导致管坯中心撕裂的压下量——临界压下量,则会恶化穿孔后毛管的内表面 In the existing two-roll oblique perforation process, the general use of the cylinder into the device will push the tube into the punch. When the tube after the contact with the roll, push the device will return to its original position, the tube in the roll to further advance by the roll and the tube between the friction to achieve. It should be noted that in order to ensure the smooth progress of the piercing process, the piercing machine of this type of piercing must have the amount of pre-piercing required to overcome the head axial resistance. It is well-known that at perforation, the pre-head reduction of more than the amount of reduction that causes tearing of the center of the tube, the critical reduction, worsens the inner surface of the pierced capillary