| 摘要 |
PURPOSE:To swage and roll tubes having different outside diameter levels from hollow tube stocks having an equal outside diameter and to summarize stock dimensions by rolling a hollow tube stock into an ellipse section stock and then strongly drafting the stock in the major axis direction to reduce, swage and roll the stock. CONSTITUTION:A hollow tube stock 10A is once formed into an ellipseshaped stock by flattening rolling by use of ellipseshaped grooved rolls 5A of a 1st stand tilted at 45 deg. to the pass line level PL. Then, an outside peripheral length of the stock is remarkably reduced by strongly drafting in the major axis direction by use of ellipse-shaped grooved rolls 5B tilted by 90 deg. to the rolls 5A of the 1st stand. Thus, an outside diameter reduction ratio in a mandrel mill is increased and a ratio of an outside diameter of a tube on the outlet side of a mandrel mill to an outside diameter of a hollow tube stock in the inlet side of the mill is optionally set to a value within a prescribed range. Hence, an outside diameter of the hollow tube stack on the inlet side of the mill is practically summarized to one level. |
