公开(公告)号：US20210101194A1

公开(公告)日：2021-04-08

申请号：US16971149

申请日：2019-01-18

Applicant: NIPPON STEEL CORPORATION

Inventor： Yasuyoshi HIDAKA ,  Yasuto HIGASHIDA ,  Naoya SHIRASAWA

IPC: B21B25/00 ,  C22C38/12 ,  C22C38/08 ,  C22C38/04 ,  C22C38/02 ,  C23C4/06 ,  C23C4/11 ,  C23C4/131

Abstract: A piercer plug with increased wear resistance is provided. A piercer plug includes: a plug body; and a sprayed coating formed on the surface of the plug body. The sprayed coating contains an iron-based alloy and oxides thereof. The chromium concentration determined by analyzing the sprayed coating with X-ray fluorescence analysis is 3 to 20 mass %.

公开(公告)号：US20220186350A1

公开(公告)日：2022-06-16

申请号：US17432146

申请日：2020-03-16

Applicant: NIPPON STEEL CORPORATION

Inventor： Seiya OKADA ,  Hiroki KAMITANI ,  Nobuaki KOMATSUBARA ,  Yusaku TOMIO ,  Shohei IKEDA ,  Naoya SHIRASAWA

IPC: C22C38/32 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/24 ,  C22C38/22 ,  C22C38/26 ,  C22C38/28 ,  C21D3/04 ,  C22C38/00

Abstract: The seamless steel pipe according to the present disclosure includes a base material and a decarburized layer formed on the surface of the base material. The chemical composition of the base material consists of, in mass %, C: 0.20 to 0.50%, Si: 0.05 to 0.50%, Mn: 0.01 to 1.00%, P: 0.0300% or less, S: 0.0100% or less, Al: 0.005 to 0.100%, Cr: 0.30 to 1.20%, Mo: 0.30 to 1.50%, Ti: 0.002 to 0.050%, V: 0.01 to 0.30%, Nb: 0.002 to 0.100%, B: 0.0001 to 0.0050%, N: 0.0100% or less, O: 0.0050% or less, and with the balance being Fe and impurities. The base material has a yield strength of 655 MPa or more, and a yield ratio of 85.0% or more. The decarburized layer has a depth of 150 μm or less.