Page 22 - ITAtube Journal 1 2019

Technical Papers
Figure 2.
used for the production of hot-rolled seamless pipes to be used for pipe couplings (casing and tubing). A hot-rolled or continuously-cast round billet with diameter from 80 mm to 250 mm is utilized as an initial workpiece for production of pipes from 70 mm to 270 mm in diameter and wall thickness from 8 mm to 28 mm. Normally, piercing of a solid bar in this stand is made in two passes. In the first pass the solid billet is rolled and contacts a plug mounted on a rod. As the workpiece moves forward under the force of the cross rolls, the workpiece makes contact with, and is pierced by, the plug, thus forming a hollow tube (or shell) from the originally solid workpiece. After the first pass, the plug is replaced with a different plug, and the distances between the rolls and guides are adjusted for the second pass. During this time, the half-rolled shell is supplied to the front side of the stand for the next pass.
Fig. 2. Process flow diagram of production of tubes on the TPA 70-270
The 3D CAD models of the working rolls, the guide shoes, and two plugs are made according to the actual sizes of the TPA 70-270 tools. The assembled model of the aggregate is shown on Fig. 3.
Fig. 3. Geometrical model of the workpiece and the tools of piercing stand TPA 70-270 for QForm simulation
Figure 3.
ITAtube Journal No1/February 2019
22