| 摘要 |
PURPOSE:To extend considerably the life of a mandrel by moving the mandrel inserted into a rough pipe together with the rough pipe until the rolling work is finished thereby preventing the mandrel from receiving local overheating by rolling. CONSTITUTION:A rough pipe A which is formed to a hollow pipe is conveyed forward to the inlet side of the guide tube 2 of a planetary type skew rolling mill B and the mandrel 3 mounted at the forward end of a mandrel bar 6 is inserted loosely and supported in the pipe A. A carriage 5 is moved in this state on a supporting device 4 and the mandrel 3 is advanced by the bar 6 to feed the pipe A into the tube 2. The pipe A is subjected to a rolling reduction by three circular conical rolls and the mandrel 3 continues to advance and moves together with the pipe A until the operation is completed. The pipe A which is completed of the reduction and elongation is moved to the next stage. The life of the mandrel 3 is extended considerably without receiving local heating. |
