Kobe Steel, Ltd.

Kabushiki Kaisha Kobe Seiko Sho

Other

Hideto Oyama

Eisuke Kurosawa

Hidetaka Kanahashi

Takehiro Nakaoka

Kazuyuki Tsutsumi

Yoshio Itsumi

Hitoshi Ishida

Daisuke Matsuwaka

Daiki Takahashi

Yasuyuki Fujii

Keitaro Tamura

Masamitsu Fujii

Akio Okamoto

Kazuki Sakamoto

Akihisa Fujita

Takayuki Kida

Kazumi Furutani

Shogo Murakami

Takeshi Kudo

Soichiro Kojima

Tadashige Nakamoto

Shinya Ishigai

Takashi Konno

Tadasu Abumiya

Keita Sasaki

Kayo Yamamoto

For continuously casting an ingot of titanium or titanium alloy, molten titanium or titanium alloy is poured into a top opening of a bottomless mold with a circular cross-sectional shape, the solidified molten metal in the mold is pulled downward from the mold, a plurality of plasma torches disposed on an upper side of molten metal in the mold such that their centers are located directly vertically above the molten metal in the mold, are operated to generate plasma arcs that heat the molten metal in the mold, and the plasma torches are moved in a horizontal direction above a melt surface of the molten metal in the mold, along a trajectory located directly vertically above the molten metal in the mold, while keeping a mutual distance between the respective plasma torches such that the plasma torches do not interfere with each other.

Continuous casting method for ingots obtained from titanium or titanium alloy

In the present invention the torch movement period is 20-40 seconds, with the torch movement period being the time required to move plasma torches (which heat the surface of molten metal in the casting mold) one time. The average heat input amount at multiple sites, which are obtained by dividing the initial solidification portion (which is where the molten metal makes contact with the casting mold and first solidifies) into multiple sites in the circumferential direction of the casting mold, is 1.0-2.0 MW/m. The molten metal advection time, which is the time required for electromagnetically stirred molten metal to travel the length of the torch heating region of the surface of the molten metal in the lengthwise direction of the casting mold, is 3.5 seconds or less.

Continuous casting device for slab comprising titanium or titanium alloy

Disclosed is a titanium or titanium alloy plate rolled in one direction, wherein a lubricating film is coated on the surface and the coefficient of sliding friction of the lubricating film-coated surface is controlled to less than 0.15. The elongation (L-El) of the titanium or titanium alloy plate in the rolling direction and the r value (T-r) in the direction perpendicular to the rolling direction have the following relation (1).(-)/(-)&#x2267;0.07&#x2003;&#x2003;(1)

Titanium or titanium alloy plate excellent in balance between press formability and strength

Heat exchanger tube

Provided is a device for titanium continuous casting () capable, even when continuously casting large diameter titanium ingots or titanium alloy ingots, of suppressing component segregation thereof. The device for titanium continuous casting () comprises: a mold () having an upper section having a circular upper opening () for pouring in molten metal (), and a bottom section having a lower opening for continuously drawing ingots (); and a plurality of plasma torches () to heat the molten metal in the mold () from the upper opening () side. The plurality of plasma torches () are disposed so that the amount of heat input to the molten metal () present in the outer circumference enclosing the center of the upper opening () is greater than the amount of heat input to the molten metal () present in the center of the upper opening ().

Titanium continuous casting device

By controlling the temperature (T) of a surface portion () of an ingot () in a contact region () between a mold () and the ingot () and/or a passing heat flux (q) from the surface portion () of the ingot () to the mold () in the contact region (), the thickness (D) in the contact region () of a solidified shell () obtained by the solidification of molten metal () is brought into a predetermined range. Consequently, an ingot having a good casting surface state can be cast.

Continuous casting method for ingot produced from titanium or titanium alloy

Disclosed is a continuous casting method in which a melt obtained by melting titanium or a titanium alloy is poured into a bottomless mold and is drawn downward while being solidified, wherein: the surface of the melt in the mold is heated by horizontally moving a plasma torch over the surface of the melt; thermocouples are provided at a plurality of locations along the circumferential direction of the mold; if the temperature of the mold measured by one of the thermocouples is lower than a target temperature, then the output of the plasma torch is increased when the plasma torch comes close to the location where that thermocouple is installed; and if said temperature is higher than the target temperature, then the output of the plasma torch is decreased when the plasma torch comes close to the location where that thermocouple is installed.

Method for continuously casting ingot made of titanium or titanium alloy

Plate for heat exchanger

Disclosed is a pure titanium sheet having a strength corresponding to JIS Grade 2 level (215 MPa in terms of 0.2% yield strength) or more and having satisfactory stamping formability. The pure titanium sheet includes titanium and inevitable impurities, has a 0.2% yield strength of 215 MPa or more, has an average grain size d of its structure of 25 &#x3bc;m or more and 75 &#x3bc;m or less, and has a hexagonal crystal structure, in which respective grains in the hexagonal crystal structure have an average of Schmidt factors (SF) of (11-22) twins with a rolling direction as axes, and the average Schmidt factor (SF) and the average grain size d satisfy following Expression (1):0.055&#x2266;[SF/&#x221a;]&#x2266;0.084&#x2003;&#x2003;(1).

Pure titanium sheet excellent in balance between stamping formability and strength

A continuous casting method in which a molten metal obtained by melting titanium or a titanium alloy is injected into a bottomless mold having a rectangular cross-section and withdrawn downward while being caused to solidify, wherein a plasma torch () is caused to rotate in the horizontal direction above the surface of the molten metal () in the mold (), and a horizontally rotating flow is generated by electromagnetic stirring on at least the surface of the molten metal () in the mold (). It is thereby possible to cast a slab in which the casting surface condition is excellent.

Continuous casting method for slab made of titanium or titanium alloy

A titanium alloy product according to the present invention: has a strength level higher than that of an existing titanium alloy product; can be successfully cold rolled (coil rolled); and is also provided with workability. In the titanium alloy product according to the invention, expensive alloy elements are not essentially required, and hence cost can be suppressed. The titanium alloy product according to the invention includes Al equivalent represented by (Al+10O (oxygen)): 3.5 to 7.2% (% by mass, the same hereinafter), Al: more than 1.0% and 4.5% or less, O: 0.60% or less, Fe equivalent represented by (Fe+0.5Cr+0.5Ni+0.67Co+0.67Mn): 0.8% or more and less than 2.0%, and one or more elements selected from the group consisting of Cu: 0.4 to 3.0% and Sn: 0.4 to 10%, in which the balance is Ti and unavoidable impurities.

Titanium alloy product having high strength and excellent cold rolling property

The continuous casting device according to the present invention enables at least some of a plurality of hearths () to be converted between being hearths () used for titanium, which are used during the continuous casting of titanium ingots, and being hearths () used for titanium alloy, which are used during the continuous casting of titanium alloy ingots. The number of hearths () used for titanium alloy is greater than the number of hearths () used for titanium. Also, the total capacity of the hearths () used for titanium alloy is greater than the total capacity of the hearths () used for titanium. Thus, titanium ingots and titanium alloy ingots can each be continuously cast by means of a single piece of equipment.

Continuous casting method and continuous casting device for titanium ingots and titanium alloy ingots

A mold () has a cooling means () for having the thermal flux at four corner sections () be smaller than the thermal flux at four face sections (). The cooling means () has first channels () which are each embedded in the four corner sections () respectively and which channel cooling water, and second channels () which are each embedded in the four face sections () respectively and which channel cooling water. The distance from the inner peripheral surface of the mold () to the first channels () is greater than the distance from the inner peripheral surface of the mold () to the second channels ().

Growing community of inventors

Takasago, Japan

Hideto Oyama