Piercing seamless steel pipe Groove adjust the main parameters are: roll distance, Guide (Guide, guide rollers) distance, ovality, feed angle, toe angle, head diameter, head under pressure before, roll rate and speed.
(1) the roller distance is around, or the shortest distance from the upper and lower roller larynx. Roller distance is usually decided by the billet diameter and total amount of pressure, is the main adjustment parameters.
(2) Guide disc (Guide, guide rollers) distance refers to the 2 Guide plate (Guide, guide rollers) the shortest distance from the root. Guide disc (Guide, guide rollers) horizontal limitations to the punch deformation and guiding role. Guide disc (Guide, guide rollers) directly affect roundness.
(3) the ellipticity is the Guide disk (Guide, guide rollers) distance and roll distance ratio. Oval degree, adjusted for Groove. Adjusting roundness to maintain a rolling cross section oval shaped, can change the degree of lateral deformation of workpiece, section perimeter control, realization of expanding and sizing. Large ellipticity increasing lateral deformation, bad for the product quality.
(4) the toe angle φ is the roll axis and the line in the angle between the projection on a horizontal plane. Barrel roll roll angle is less than 5 °. Diameter of 250 mm precision rolling unit of cone roll piercer roll angle is 10 ° ~15 °.
Rolling "cone" with the rolling angle about. Toe angle larger rolling seamless steel pipe diameter from the end (bite-side) to the end (throwing side), the greater the change, roll peripheral speed and direction along the rolling line speed increases, the greater. On one hand, increasing speed along the line direction to improve velocity and extension of enhanced metal deformation favourable, on the increasing roll rate, rolling torsion effects also increases. These two factors to considered when the roll shape design. Meanwhile, excessive toe angle, it also becomes more difficult to design.
(5) feed angle is the roll axis and the line projection angle in the vertical plane. Diameter of 250 mm precision rolling of seamless steel pipe unit of cone roll piercer feed angle is 5 ° ~12 °. Larger the feed angle, roll speed in the direction of greater weight, seamless move faster, but greater skew rolling extension of pitch, punch load is larger.
(6) the inner diameter of the head diameter and piercing related. In General, larger head diameter, perforation of seamless steel tube of greater diameter.