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    22.
    发明专利
    未知

    公开(公告)号：ID23961A

    公开(公告)日：2000-06-08

    申请号：ID991128

    申请日：1999-12-08

    Applicant: SUMITOMO METAL IND

    Inventor： AMAYA HISASHI ,  ANRAKU TOSHIRO ,  HIDAKA YASUYOSHI

    IPC: C21D7/06 ,  B21C43/00

    Abstract: A martensitic stainless steel product having a chromium content of 9 to 15 % by weight and a surface from which mill scales generated during production are removed by a shot blasting. The surface satisfies that, when a color image of the surface taken with 640 x 480 pixels is analyzed on blue color and a histogram of the pixel numbers and the tones divided into 0 to 255 classes is obtained, a relationship between the maximum frequency Yp and the tone value Xp at which Yp is counted satisfies an inequality, 800Xp - Yp - 27000 > 0. This steel product is superior in weatherability under atmospheric environments, and also superior in sulfide stress cracking resistance under environments containing hydra-sulfide.

    23.
    发明专利
    未知

    公开(公告)号：BRPI0712692A2

    公开(公告)日：2013-04-24

    申请号：BRPI0712692

    申请日：2007-05-21

    Applicant: SUMITOMO METAL IND

    Inventor： HIDAKA YASUYOSHI ,  MATSUMOTO SATOSHI ,  ONO TOSHIHIDE ,  NAKAIKE KOUJI ,  IIDA SUMIO

    IPC: B21B25/04 ,  B21B23/00 ,  C21D3/04 ,  C21D9/08

    Abstract: A process for producing seamless pipes which comprises conducting a piercing rolling step, a elongating rolling step using a mandrel bar, and a sizing rolling step and subsequently conducting a product heat treatment. In the process, when the carbon-equivalent weight, namely the sum of the weight of graphite in the lubricant and the carbon content in the organic binder, per unit area of the lubricant adhering to the mandrel bar surface in the above-mentioned step of elongating rolling is expressed by C (g/m 2 ) or the maximum extent of carburization in the inner surface of the pipe to be heat-treated but prior to the heat treatment is expressed by ”C (% by mass), the heating temperature for the pipe to be heat-treated is expressed by T (°C), and the time during which a decarburizing gas is blown into the inside of the pipe to be heat-treated is expressed by t 1 or t 2 (seconds), and further, the blowing time calculated taking into account the wall thickness reduction in the step of cold working is expressed by t 3 or t 4 (seconds), a predetermined relation is satisfied and the actual decarburizing gas blowing time in the heat treatment is longer than the time t 1 , t 2 , t 3 or t 4 (seconds), whereby seamless stainless steel pipes reduced in carburized layer formation can be produced even when the carbon adhesion to the pipe inner surface is caused in, for example, mandrel mill rolling.

    24.
    发明专利
    未知

    公开(公告)号：BRPI0712244A2

    公开(公告)日：2012-01-17

    申请号：BRPI0712244

    申请日：2007-04-26

    Applicant: SUMITOMO METAL IND

    Inventor： HIDAKA YASUYOSHI ,  MATSUMOTO SATOSHI ,  ONO TOSHIHIDE ,  NAKAIKE KOUJI ,  IIDA SUMIO ,  NOGAMI HIROSHI

    IPC: B21B17/14 ,  B21B23/00 ,  B21B25/04 ,  C21D8/10 ,  C22C38/00 ,  C22C38/18 ,  C22C38/58

    Abstract: A process for stainless-steel pipe production which comprises piercing and rolling a raw material stainless steel containing, by mass, Cr: 10-30%, to give a hollow shell, elongating rolling the hollow shell using a mandrel bar, together with a graphite-free lubricant, to give a finishing rolling blank pipe and heating the blank pipe in a reheating furnace and subjecting the same to finishing rolling by sizing rolling to produce a hot-finished pipe, and then subjecting this pipe as a mother pipe to cold working to produce a stainless-steel pipe. In the reheating furnace, the finishing rolling blank pipe is heated to 1000°C or more and subjected to heating in which an oxidizing gas is blown into the pipe inside, whereby a stainless-steel pipe which is inhibited from forming a carburized layer in the pipe inner surface can be produced. When the finishing rolling by sizing rolling to give a cold working mother pipe is carried out by stretch reducer rolling at 860-1050°C, an annealing heat treatment of the mother pipe for cold working can be omitted. Thus, a stainless-steel pipe having excellent surface quality can be efficiently produced.

    27.
    发明专利
    未知

    公开(公告)号：NO996015D0

    公开(公告)日：1999-12-07

    申请号：NO996015

    申请日：1999-12-07

    Applicant: SUMITOMO METAL IND

    Inventor： AMAYA HISASHI ,  ANRAKU TOSHIRO ,  HIDAKA YASUYOSHI

    IPC: C21D7/06 ,  C22C

    Abstract: A martensitic stainless steel product having a chromium content of 9 to 15 % by weight and a surface from which mill scales generated during production are removed by a shot blasting. The surface satisfies that, when a color image of the surface taken with 640 x 480 pixels is analyzed on blue color and a histogram of the pixel numbers and the tones divided into 0 to 255 classes is obtained, a relationship between the maximum frequency Yp and the tone value Xp at which Yp is counted satisfies an inequality, 800Xp - Yp - 27000 > 0. This steel product is superior in weatherability under atmospheric environments, and also superior in sulfide stress cracking resistance under environments containing hydra-sulfide.

    30.
    发明专利
    未知

    公开(公告)号：BRPI0810054A2

    公开(公告)日：2014-10-21

    申请号：BRPI0810054

    申请日：2008-02-04

    Applicant: SUMITOMO METAL IND

    Inventor： HIDAKA YASUYOSHI ,  HIRASE NAOYA ,  KOUCHI YASUHIRO

    IPC: B21B25/00

    Abstract: A plug material having a prescribed shape is prepared, the prepared plug material is thermally treated in a heat treatment atmosphere that contains at least 1.0 vol.% oxygen at a heat treatment temperature of at least 950°C and less than 1050°C and thus a plug having an oxide scale layer 30 on the surface is manufactured. According to the manufacturing method, pores PO that extend along the surface SF of the plug material are formed under outer scale layer 20 in the oxide scale layer 30, which allows cracks to be more easily propagated in the outer scale layer 20. Therefore, the outer scale layer 20 is more easily peeled off than the conventional one.

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