Deformation zone of thermal expansion seamless steel pipe

Thermal expansion seamless steel pipe deformation zone is divided into three parts: the flattening reducing region, reducing zone, turn round area.

Flattening reducing deformation: seamless steel billet was first contacted state cantilever tapered roll forward under the action of friction. In this case, only the seamless steel billet into contact with the roll not in contact with the plug. The deformation is mainly flattening reducing deformation. When reducing excessive thickening of the wall sometimes. Reducing the size of flattened area has a relationship with the head position, head position adjustment is mainly in order to successfully achieve a blank tube and bite and bite into the secondary wall-expanding deformation mechanics and kinematics to create good conditions.

Wall-expanding deformation: oblique rolled seamless steel pipe thermal expansion of the main deformation zone. In this area blank tube wall and the enlarged diameter reduction occurs. Since the extension coefficient close to 1, according to the law of constant volume of metal, metal wall thinning due almost entirely into the outer diameter increases need to add metal. Deformation of the metal occurs mainly in the circumferential and radial blank tube. Since the rolls and the plug can be along each axis direction, so long as the change rolls and head position, you can change the system to expand the mother pipe specifications. When the position adjustment of rolls and head, reduce the amount of deformation in the wall region does not change.

Turn round deformation: after the blank tube through the wall of expanding deformation reduced, no longer turn into the circle area in contact with the head. In the role of surface friction, smooth out blank pipe deformation zone.