It is directly roll the steel strip and bend it to square & rectangular shape, then weld it to finish the formation.
 
Characteristics and Advantages:

1).Compare with round into square&rectangle forming way,this way is better for the shape at the edge of cross section,comparatively, semi-diameter of inner arc is Small,and the brim is flat,outlook is regular.
2).the whole line load is low ,especially the sizing parts.
3).The width of steel strip is small about 2.4-3% than round into square & rectangle,it can save the consume of raw material.
4).It adapt the multi-point bending way, avoid the axial force and side abrasion, reduce the forming step while ensure the quality,meanwhile it reduce the power wastage and roller abrasion.
5).It adapt the combined type roller on the most of the stands,it realize that one set of roller can produce dozens of square&rectangle  pipe with different specification,it decrease the store of roller,low the cost about 80% on roller, Fast the bankroll turnover, short the time one new product design.
 
Note: We can design and manufacture pipe making machine according to customers' requirements.