| 摘要 |
PURPOSE:To roll a blank pipe and extract a mandrel without being subjected to bad effect by rotating the mandrel bar of a mandrel mill for manufacturing a pipe in inserting it through the inside of a lubricant coating device in its axial direction. CONSTITUTION:A mandrel bar 2 is inserted into the inside of a hollow blank pipe, and is extracted after rolling the pipe and is cooled to be used in cycles after coating a lubricant on the surface of its desired part by a lubricant-spraying ring nozzle 11 located on the way of transferring the pipe. The bar 2 is advanced in the nozzle 11 in its axial direction by rotating drum-shaped rolls 23, 23..., slanted each by an angle alpha with respect to the line 25 perpendicularly intersecting with the axial line of bar 2 and arranged in series at prescribed intervals. Then, the lubricant is coated on the surface of bar 2 while it is rotated, and the unformed part and stripping part of lubricant caused by the contact of rolls 23 at the times before and after drying the lubricant are formed into spiral shapes. Thus, the lubricant films can be formed again on said parts on the way of rolling, and the expected purpose is achieved. |
