JP2006159233A - Method for changing size in cold pilger mill rolling - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for performing size change by using a short dummy pipe without using a pipe stock to be next rolled when performing the size change by which the size is greatly changed in cold Pilger mill rolling. <P>SOLUTION: In the method for performing the size change in the cold Pilger mill rolling, a pushing pipe with which a preceding pipe is just passed through a accurate pressure die, is inserted before a succeeding pipe and rolling is changed to the rolling of the succeeding pipe at the point of time when the preceding pipe is passed through the accurate pressure die or a claw at the outlet. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for resizing a cold pilger mill.

  In general, when the dimensions of a product change greatly in the rolling process in a cold pilger mill, if the dimensions are changed using the raw tube to be rolled next, at least until the preceding rolled material exits the precision die or outlet claw. There is a problem that the yield is reduced because the size of the rolled product of the succeeding rolled material is greatly changed and one of the succeeding rolled material becomes scrap. As a method for improving the yield in spite of the change of the dimension and thickness of the product in such a rolling process, for example, JP-A-7-246415 (Patent Document 1) and JP-A-6-179003 (Patent Document) As disclosed in the literature 2), the former means that the roll gap is changed, the crop loss due to the thickening of the pipe end is reduced, and a uniform circumferential thickness is produced, and the latter is the hollow shell tip. At the time when is inserted into the final stand, the mandrel protrusion length is changed to change the wall thickness.

JP 7-246415 A JP-A-6-179003

  Patent Documents 1 and 2 described above both relate to the thickness change in the rolling process, and are common in changing the product in the rolling process, but the yield improvement in cold pilger mill rolling accompanying the dimension change. It is not useful for countermeasures. The problem to be solved by the present invention is to provide a method for resize using a dummy short pipe, instead of using a raw pipe to be rolled next, when performing resize with greatly changing dimensions. is there.

The means for solving the problems of the present invention is to use a short push tube instead of the next raw tube to be resized when performing the size change.
The gist of the invention is that in the method of changing dimensions in cold pilger mill rolling, the preceding rolled material is inserted into the precision die, or a push tube that only exits the outlet claw before the subsequent rolled material, At the time when the preceding rolled material exits the precision die, it is changed to the rolling of the subsequent rolled material, and there is a dimensional change method in cold Pilger mill rolling.

  As described above, according to the present invention, the amount of dimensional defects thrown away when changing dimensions with a cold pilger mill is greatly reduced, which is extremely effective industrially.

The present invention will be described below with reference to the drawings.
FIG. 1 is an explanatory diagram of rolling in a roll stand 1 of a cold pilger according to the present invention. As shown in FIG. 1, in rolling in a cold piller in a roll stand 1, the thickness of the product is adjusted by a mandrel 3 attached to the tip of a mandrel rod 2, and the roll shaft reciprocates in the roll stand 1. The outer diameter of the product is adjusted with 4 and the outer diameter is adjusted with the precision pressure die 5. When the outlet claw is used without using the pressure die, the product is held by the outlet claw.

  In this case, when changing the dimensions of the product, the mandrel 3, the roll shaft 4, the pressure die 5 or the outlet claw must be replaced. In order to replace the precision die 5 or the outlet claw, the previous product 8 must be rolled until it passes through the precision die 5 or the outlet claw. When rolling until the product 8 comes off, the dimension of the next blank tube 6 becomes the same as that of the previous product, and the tip of the next product becomes a product of the same size as the rolling of the preceding material. become.

  The defective product must be rounded down to 1/3 of the total length of the tube. In order to shorten the dimensionally defective product as much as possible, in the present invention, a short push tube 7 is inserted between the previous product and the next size of the raw tube, and the product is formed from the precision die 5 or the outlet claw. If the short push tube 7 is thrown away when 8 is removed, the amount of waste can be reduced to less than half of the conventional amount.

  Hereinafter, the present invention will be specifically described with reference to examples. As described above, the dimensions were changed using a short push tube when the dimensions were changed with a cold Pilger mill. For example, the outer diameter of the leading element tube is 100 mm, the thickness is 10 mm, the outer diameter of the preceding product is 62.8 mm, the outer diameter is 4 mm, the outer diameter of the succeeding element tube is 100 mm, the outer diameter is 61.1 mm, and the thickness is 5.15 mm. When changing to, a push tube having an outer diameter of 10 mm, a wall thickness of 10 mm, and a length of 700 mm is inserted between the preceding and succeeding element tubes. When the rear tube is resized, if the length of the rear tube is 4800 mm, for example, about 1600 mm must be discarded as a defective dimension, but if a push tube is used, only 700 mm is discarded. Good. As a result, the amount to be cut off is less than half compared to the conventional method. For example, if the number of resizes per month is 780 times, when the push tube according to the present invention is not used, the product is equivalent to 780 products. However, it became possible to reduce this amount and the yield was greatly improved.

It is explanatory drawing of the rolling in the roll stand of the cold pilger which concerns on this invention.

Explanation of symbols

1 Roll Stand 2 Mandrel Rod 3 Mandrel 4 Roll Shaft 5 Precision Die or Outlet Claw 6 Raw Tube before Rolling 7 Short Push Tube 8 Product after Rolling

Patent Applicant Sanyo Special Steel Co., Ltd.
Attorney: Attorney Shiina

Claims (1)

In the method of changing dimensions in cold pilger mill rolling, a push tube that allows the preceding rolled material to exit the precision die is inserted before the subsequent rolled material, and the preceding rolled material is the precision die or outlet claw. The method of changing dimensions in cold pilger mill rolling is characterized by changing to rolling of a subsequent rolled material when exiting from.

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