Spiral steel pipe and the mandrel by rolling contact with a number of vertical rack rolling deformation systems, pipe deformation and movement as well as by the role of the roll and the mandrel, while on the roll and the mandrel counterproductive. Rotating roll deformation is the main tool, deformation force is applied to the metal, and will determine the flow state of the metal. The mandrel may be passive (full dynamic quenching), namely to drive entirely of metal, it can be active (stopper), the movement of the core holding the metal can affect the deformation of the metal affected by the work rolls. Throughout the continuous rolling process is such an action and reaction between the workpiece and tool. Roll between the mandrel and the metal contact and mutual restriction unity of opposites. Grasp the link between them and the restrictive relationship, that is, the basic task of rolling steel theory.
Steel rolling pass shape due to the role of the metal ring to pass along the uneven pressures, namely steel rolling deformation zone in a three-dimensional deformation. Mechanical characteristics of grooved rolling tubes from view, deformation zone to flow on the metal ring around the hoop tension distribution and the distribution of the friction ring to the unit a great impact, thus affecting the unit rolling force, friction, and other vertical units accurate calculation of the parameters. According to the metal in contact with the tool or not, pipe deformation zone can be divided into contact and non-contact deformation zone deformation zone. The contact metal by deformation zone limiting the tool surface and a radial displacement, and its surface contact with the radial flow speed can be determined at the tool geometry.
In the rolling pass, pass along the width of the spiral pipe wall thickness is uneven compression top largest maximum extension, side compression minimum, extend also the smallest. But in fact the continuity of deformation of the metal, the metal part of the actual extension of the end portion while ignoring the condition should be averaged. This phenomenon occurs not only in a uniform deformation zone outlet, but also in the deformation zone. Deformation of the cross-sectional area up speed difference metal and metal is small compared to the total velocity, it can be similar to that of the point of death metal section the same speed, which is usually referred to plane strain assumptions. However, the roll peripheral speed of pass points not same, which can have a different distribution of slip zone.
