Nippon Steel Sumitomo Metal Corporation

Sumitomo Metal Industries, Inc.

Nippon Steel Corporation

Yasuyoshi Hidaka

Yasuto Higashida

Kazuhiro Shimoda

Kouji Nakaike

Tomio Yamakawa

Sumio Iida

Naoya Hirase

Shuichi Akiyama

Satoshi Matsumoto

Hirokazu Okada

Hiroshi Nogami

Hisashi Amaya

Tomohiro Yamamoto

Keishi Matsumoto

Osamu Miyahara

Toshiro Anraku

Toshihide Ono

Yasuhiro Masaki

Manabu Kanzaki

Takahisa Kato

Tatsuya Miyai

Yuichi Yamanari

Naoya Shirasawa

Yuji Arai

Yuji Yamamoto

Tetsuya Nakanishi

Kenji Takeuchi

Yoshihiko Hayashi

Yuji Inoue

Kazutaka Asabe

Kenichi Saitou

Kouji Yamane

Mitsuru Yoshizawa

Yasumitsu Kondo

Yukimasa Ueda

Aya Fujita

Yosuke Tatebayashi

Akihiro Uehira

Shusuke Shimooka

Takateru Inage

Koji Muramatsu

Junichi Nishimori

Masaharu Nakamori

Kei Murata

Jyun Nagakita

Fumihito Yoshikawa

Takayuki Aisaka

Atsushi Nosaka

Yasuhiro Kouchi

Ryuutarou Ogata

Koji Nakaike

Hiroki Kusuda

Seiji Miyamoto

Masami Sakiyama

Takayoshi Kagari

Yuta Yokomizo

Kotaro Ona

Yasufumi Kitamura

Wataru Nohara

Kosuke Hayashi

A piercer plug with increased life and a method of manufacturing it are provided. The piercer plugincludes a tip portionand a trunk portionmade of the same material as the tip portionand continuous to the tip portion. The trunk portionincludes a cylindrical portionhaving a hole used for attaching a bar. The tip portionis harder than the cylindrical portion

Piercer plug and method of manufacturing the same

A piercer plug with increased recyclability is provided. A piercer plug () has a chemical composition of, in mass %: 0.15 to 0.30% C; 0.4 to 1.2% Si; 0.2 to 1.5% Mn; 0.1 to 2.0% Ni; 0 to 4.0% Mo and 0 to 4.0% W, where the total content of Mo and W is 1.0 to 6.0%; higher than 1.0% and not higher than 4.0% Cr; 0 to 0.2% B; 0 to 1.0% Nb; 0 to 1.0% V; 0 to 1.0% Ti; and balance Fe and impurities, the plug including a tip portion () and a trunk portion () made of the same material as the tip portion () and contiguous to the tip portion (). The trunk portion () includes a cylindrical portion () having a hole used to mount a bar. The tip portion () is harder than the cylindrical portion ().

A piercer plug having good base-material deformation resistance is provided. A method of manufacturing a piercer plug () includes the steps of; preparing a plug body () including a tip portion () and a cylindrical portion () having a hole () usable to attach a bar and located rearward of the tip portion (); forming a build-up layer () on the surface of the tip portion (); and heating the plug body () such that the temperature of the tip portion () with the build-up layer () formed thereon is not lower than the austenite transformation temperature and the temperature of the cylindrical portion () is lower than the austenite transformation temperature.

Method of manufacturing piercer plug

A piercing plug includes a plug main body, and a sprayed coating which is formed on a surface of the plug main body and includes iron and iron oxide. A chemical composition of the sprayed coating includes, in addition to the iron and the iron oxide, by mass %, C: 0.015% to 0.6%, Si: 0.05% to 0.5%, Mn: 0.1% to 1.0%, and Cu: 0 to 0.3%.

Piercing plug and manufacturing method of piercing plug

A piercing plug of the present invention includes: a plug body; a Ni&#x2014;Cr layer formed on a surface of the plug body; and a sprayed coating formed on a surface of the Ni&#x2014;Cr layer. The plug body contains, by mass %, 20 to 30% of Cr, 30 to 55% of Ni, 0.005 to 0.5% of C, 0.1 to 1.0% of Si, 0.2 to 1.5% of Mn, and at least one of Mo and W which satisfy a following conditional expression (A), and remainder including Fe and impurities.1.5%&#x2264;Mo+0.5W&#x2264;8.5%&#x2003;&#x2003;(A)

Piercing plug

Provided is a method for producing a plug for use in a piercing-rolling mill for producing a seamless steel tube/pipe, and the method for producing the plug for piercing-rolling comprises shotblasting a surface of the plug, and arc-spraying a spray wire so as to form a film on a surface of a base metal of the plug that is shotblasted. In the arc-spraying step, the arc spraying is carried out by using, as the spray wire, a cored wire whose iron sheath tube is charged with at least iron oxide particles among iron particles and the iron oxide particles (one or more of FeO particles, FeOparticles, and FeOparticles), so as to form the film containing iron oxide and Fe. Accordingly, it is possible to enhance the production efficiency of the plug, and to produce the plug for piercing-rolling capable of securing the steady enhancement of the durability life of the plug during the piercing-rolling.

Method for producing plug for piercing-rolling

Provided is an equipment system for producing a piercing-rolling plug to be used for producing a seamless steel tube/pipe, which includes a shotblasting device for applying shotblasting on a surface of the plug, and an arc-spraying device for performing arc-spraying of iron wires on a surface of a base metal of the plug to which the shotblasting is applied, so as to form a film containing oxide and Fe thereon. The arc-spraying device includes plural spraying booths each of which separately forms part of the film in turn in each of sections into which the surface of the base metal of the plug is divided along an axial direction of the plug. The production efficiency of the plug can therefore be maintained at a high level, and steady enhancement of the durability life of the plug can be realized during the piercing-rolling.

Equipment system for producing piercing-rolling plug

It is an objective to provide a plug capable of enhancing a usage count of the plug, which is for use in a piercing machine for piercing-rolling a billet, and a regenerating method of the plug. The plug () is for use in a piercing machine () for piercing-rolling a billet (). The plug () includes a body (), a columnar portion (), and a sprayed film (). The body () has a maximum diameter at its rear end. The columnar portion () has the same diameter as the diameter of the rear end of the body (), and extends from the rear end of the body (). The sprayed film () is formed on a surface of the body () and on a surface of the columnar portion ().

Method for regenerating a plug for use in a piercing machine

There is provided a Cr-containing austenitic alloy having a chromium oxide film with a thickness of 5 nm or larger on the surface, wherein the content of Mn in a base metal is, by mass percent, less than 0.1%. The chemical composition of the base metal desirably consists of, by mass percent, C: 0.15% or less, Si: 1.00% or less, Mn: less than 0.1%, P: 0.030% or less, S: 0.030% or less, Cr: 10.0 to 40.0%, Ni: 8.0 to 80.0%, Ti: 0.5% or less, Cu: 0.6% or less, Al: 0.5% or less, and N: 0.20% or less, the balance being Fe and impurities.

Cr-containing austenitic alloy and method for producing the same

There is provided a seamless steel pipe for line pipe, wherein a chemical composition consists, by mass percent, of C: 0.03-0.10%, Si: &#x2266;0.50%, Mn: 1.0-2.0%, P: &#x2266;0.050%, S: &#x2266;0.005%, Cr: 0.05-1.0%, Mo: 0.01-0.30%, Al: 0.001-0.10%, N: &#x2266;0.01%, Ni: 0.04-2.0%, Ca: 0.0005-0.0050%, Cu: 0-2.0%, Ti: 0-0.05%, Nb: 0-0.05%, V: 0-0.10%, the balance: Fe and impurities, and satisfies the conditions of Cu+Ni: &#x2267;0.10%, and Mo+V: &#x2266;0.30%, wherein in a scale formed on the surface of the steel pipe, metal particles consisting mainly of Ni or Cu having an average circle-equivalent diameter of 0.1-5 &#x3bc;m exist, and a distance from a boundary between the base metal of the steel pipe and the scale to a region in which the metal particles do not exist is 20 &#x3bc;m or longer.

Seamless steel pipe for line pipe

There is provided a chromium-containing austenitic alloy wherein at least one surface of the surfaces of the alloy has a continuous chromium oxide film with a thickness of 5 nm or more and less than 50 nm. A maximum current density determined by a critical passivation current density method is 0.1 &#x3bc;A/cmor less when the chromium oxide film is continuous. A chemical composition of a base metal preferably consists of, by mass percent, C: 0.15% or less, Si: 1.00% or less, Mn: 2.0% or less, P: 0.030% or less, S: 0.030% or less, Cr: 10.0 to 40.0%, Ni: 8.0 to 80.0%, Ti: 0.5% or less, Cu: 0.6% or less, Al: 0.5% or less, and N: 0.20% or less, the balance being Fe and impurities.

Chromium-containing austenitic alloy

A plug for hot tube-making includes: a plug main body; a build-up layer formed around an axis of the plug main body on a surface of the plug main body; and a sprayed coating formed on a surface of the build-up layer.

Plug for hot tube-making

To increase the life of a plug used in a piercing machine for piercing-rolling a billet. The plug () is used in a piercing machine () that piercing-rolls a billet (). The plug () includes a plug body (), a build-up layer (), and a sprayed film (). The build-up layer () is formed on a surface of the plug body (). The sprayed film () covers at least an area ranging from the rear end of the build-up layer () to a position of the maximum outer diameter of the plug body ().

Plug used in piercing machine

The present invention provides a lubricant composition for hot metal working which is capable of inhibiting generation of flaws on the surface of materials to be provided for hot metal working, and provides a method of hot metal working. The invention provides a lubricant composition for hot metal working comprising a plurality of glass frits respectively having different softening point from each other.

Lubricant composition for hot metal working and method of hot metal working using the same

There is provided an antioxidant agent capable of preventing scale from being produced on the surface of a heated metallic starting material more effectively than the conventional antioxidant agent. The antioxidant agent according to the present invention contains a plurality of glass frits having different softening points and an inorganic compound having a melting point not higher than 600&#xb0; C. The inorganic compound mainly softens in the low-temperature range of about 600&#xb0; C. The plurality of glass frits mainly soften in the low-temperature range of about 600 to 1300&#xb0; C. Therefore, the antioxidant agent covers the surface of metallic starting material in a broad temperature range, oxidizes the surface of metallic starting material, and prevents the production of scale.

Antioxidant agent and process for producing metallic material

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Tokyo, Japan

Yasuyoshi Hidaka