Title:
METHOD FOR SUPPRESSING SURFACE INDENTATION FLAW IN ELEMENT TUBE FOR SEAMLESS STEEL TUBE
Document Type and Number:
WIPO Patent Application WO/2011/151995
Kind Code:
A1
Abstract:
An element tube (an element tube for a seamless steel tube) to which straightening by a straightener is applied after heat-transferred and tube-made, and which is then submitted to cold working, wherein, during the straightening by the straightener, cooling water is sprayed all over the surfaces of rolls (1a, 1b) constituting the straightener, and soft reduction is applied to the element tube with the loads added to the straightener rolls (1a, 1b) as 550 kN or less, thereby making it possible to effectively suppress surface indentation flaws occurring in the element tube for the seamless steel tube. It is effective as a means for the soft reduction to use a hot straightener for adding straightening such as bend removal to the element tube in a temperature range of 500-550˚C inclusive after heat-transferred and tube-made. It is desirable to perform the spraying of the cooling water all over the surfaces of the rolls (1a, 1b) by one or more means of the increased wide angle of the tip shape of cooling water nozzles, the proper arrangement of the cooling water nozzles, and an increase in the water volume of cooling water to be sprayed.
Inventors:
INUZUKA, Ryohei (5-33, Kitahama 4-chome, Chuo-ku, Osaka-sh, Osaka 41, 〒5410041, JP)
犬塚 僚平 (〒41 大阪府大阪市中央区北浜四丁目５番３３号住友金属工業株式会社内 Osaka, 〒5410041, JP)
犬塚 僚平 (〒41 大阪府大阪市中央区北浜四丁目５番３３号住友金属工業株式会社内 Osaka, 〒5410041, JP)
Application Number:
JP2011/002907
Publication Date:
December 08, 2011
Filing Date:
May 25, 2011
Export Citation:
Assignee:
SUMITOMO METAL INDUSTRIES, LTD. (5-33, Kitahama 4-chome Chuo-ku, Osaka-sh, Osaka 41, 〒5410041, JP)
住友金属工業株式会社 (〒41 大阪府大阪市中央区北浜四丁目５番３３号 Osaka, 〒5410041, JP)
INUZUKA, Ryohei (5-33, Kitahama 4-chome, Chuo-ku, Osaka-sh, Osaka 41, 〒5410041, JP)
住友金属工業株式会社 (〒41 大阪府大阪市中央区北浜四丁目５番３３号 Osaka, 〒5410041, JP)
INUZUKA, Ryohei (5-33, Kitahama 4-chome, Chuo-ku, Osaka-sh, Osaka 41, 〒5410041, JP)
International Classes:
B21D3/02; B21D3/00
Attorney, Agent or Firm:
MORI, Michio et al. (M. MORI PATENT OFFICE, 17-23 Higashinaniwa-cho 5-chome, Amagasaki-sh, Hyogo 92, 〒6600892, JP)
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Claims: