The two-roll oblique rolling piercer consists of two double barrel-shaped rolls, so it is called barrel piercing. The axis of the roll is at a certain angle of inclination with the axis of the rolling mill, so it is also called cross-rolling. The two rollers rotate in the same direction during operation. The billet enters along the rolling direction. After the billet is bitten by the roller, it rotates and moves forward under the action of the rolling force (that is, the billet material is spirally moved). There is no solid conical core at the front end of the tube blank. Rolling principle
Pros and cons of two-roller cold-rolled pipe
Two-roller cold rolled tube method has the following advantages:
- (1) The pass processing rate is large, and the maximum processing rate can reach more than 80%, especially suitable for the processing of titanium alloys and alloy pipes with low cold workability;
- (2) It can produce pipes with a long length, up to 30m;
- (3) Omit or reduce the annealing and intermediate annealing of some alloys, the production efficiency is high, and the cycle is short;
- (4) The high degree of automation of the equipment can reduce labor intensity;
- (5) Easy to change the hole pattern, convenient and quick size adjustment;
- (6) It can produce special-shaped pipes and variable-section pipes.
The main disadvantages of the two-roller cold milk tube method are:
- (1) The structure of the cold rolling mill is complex, the equipment accuracy is high, and the investment and maintenance costs are large
- (2) The design and manufacture of tools are relatively complicated;
- (3) The rolled pipe has large ellipticity, corrugation, ribs, etc., and the deviation of the outer diameter of the pipe is not easy to control. Therefore, the rolled pipe must meet the requirements of the finished pipe after being stretched and reduced and adjusted .