Nippon Steel Corporation

Nippon Steel & Sumitomo Metal Corporation

Toho Titanium Co., Ltd.

Tomonori Kunieda

Kazuhiro Takahashi

Hideki Fujii

Yoshitsugu Tatsuzawa

Kenichi Mori

Akira Kawakami

Hiroaki Otsuka

Hisamune Tanaka

Takashi Oda

Yoshimasa Miyazaki

Osamu Tada

Ryotaro Miyoshi

Yoshihiro Fujii

Tatsuo Yamazaki

Tomoyuki Kitaura

Norio Yamamoto

Hidenori Takebe

Koji Mitsuda

Motomi Masaki

Sosuke Nishiwaki

A bar includes a titanium alloy containing an α phase and a β phase, in which the titanium alloy contains, as a chemical composition, by mass %: Al: 4.5% to 6.4%; Fe: 0.5% to 2.1%; C: 0.01% or less; N: 0.05% or less; O: 0.25% or less; V: 0.10% or less; Si: 0% to 0.40%; Ni: 0% to 0.15%; Cr: 0% to 0.25%; Mn: 0% to 0.25%; and a remainder including Ti and impurities, an area ratio of the β phase in a metallographic structure of the titanium alloy is 20% or less, and an average minor axis length of grains of the β phase is 2.0 μm or less.

An α+β type titanium alloy wire contains, in mass %, Al: 4.50 to 6.75%, Si: 0 to 0.50%, C: 0.080% or less, N: 0.050% or less, H: 0.016% or less, O: 0.25% or less, Mo: 0 to 5.5%, V: 0 to 4.50%, Nb: 0 to 3.0%, Fe: 0 to 2.10%, Cr: 0 to less than 0.25%, Ni: 0 to less than 0.15%, Mn: 0 to less than 0.25%, and the balance being Ti and impurities, the contents of Al, Mo, V, Nb, Fe, Cr, Ni, and Mn satisfying an equation, in which an average aspect ratio of an α crystal grain is 1.0 to 3.0, a maximum crystal grain diameter of the α crystal grain is 30.0 μm or less, an average crystal grain diameter of the α crystal grain is 1.0 to 15.0 μm.

α+β type titanium alloy wire and manufacturing method of α+β type titanium alloy wire

Provided is a titanium cast product for hot rolling made of commercially pure titanium, the titanium cast product including a melted and resolidified layer in a range of more than or equal to 1 mm in depth on a surface serving as a rolling surface, the melted and resolidified layer being obtained by adding one or more elements out of any one of or both of at least one &#x3b1; stabilizer element and at least one neutral element to the surface, and melting and resolidifying the surface. An average value of a total concentration of the at least one &#x3b1; stabilizer element and the at least one neutral element in the range of more than or equal to 1 mm in depth is higher than a total concentration of the at least one &#x3b1; stabilizer element and the at least one neutral element in a base metal by, in mass %, more than or equal to 0.1% and less than 2.0%.

Titanium cast product for hot rolling unlikely to exhibit surface defects and method of manufacturing the same

A method for producing a hot-rolled titanium plate includes, [1] melting at least one part of the side surface of the titanium slab by radiating a beam or plasma toward the side surface, not toward the surface to be rolled, and thereafter causing re-solidification to form, in the side surface, a layer having grain diameter of 1.5 mm or less and a depth of 3.0 mm or more from the side surface; [2] performing a finishing process on the surface to be rolled of the titanium slab in which the layer is formed, to thereby bring a slab flatness index X to 3.0 or less; and [3] subjecting the titanium slab after the finishing process to hot rolling under a condition in which a length of an arc of contact of a roll L in a first pass of rough rolling is 230 mm or more.

Method for producing hot-rolled titanium plate

A titanium alloy material contains: in mass %, Cu: 0.7% to 1.4%; Sn: 0.5% to 1.5%; Si: 0.10% to 0.45%; Nb: 0.05% to 0.50%; Fe: 0.00% to 0.08%; O: 0.00% to 0.08%; and the balance composed of Ti and impurities, in which in a structure, an area fraction of an &#x3b1; phase is 96.0% or more and an area fraction of an intermetallic compound is 1.0% or more, and an average crystal grain size of the &#x3b1; phase is 10 &#x3bc;m or more and 100 &#x3bc;m or less and an average grain size of the intermetallic compound is 0.1 to 3.0 &#x3bc;m.

Titanium alloy material

A titanium composite materialis provided that includes: an inner layerconsisting of a commercially pure titanium or a titanium alloy; an outer layerformed on at least one surface of the inner layerand having a chemical composition that is different from a chemical composition of the inner layer; and an intermediate layer formed between the inner layerand the outer layerand having a chemical composition that is different from the chemical composition of the inner layer. The thickness of the outer layeris 2 &#x3bc;m or more, and occupies no more than 40% of the overall thickness per side. The thickness of the intermediate layer is 0.5 &#x3bc;m or more. Despite being inexpensive, this titanium composite material has desired characteristics.

Titanium composite material and titanium material for hot rolling

A titanium material for hot rollingincludes a titanium cast piece, and titanium sheetsthat are welded to faces corresponding to rolling surfacesof the titanium cast piece. The titanium cast pieceand the titanium sheetshave the same kind of chemical composition. The titanium material for hot rollingcan maintain good surface properties after hot rolling even if a slabbing process or a finishing process is omitted.

Titanium material for hot rolling

Provided is a titanium cast product for hot rolling made of commercial pure titanium or a titanium alloy, the titanium cast product including, in a surface serving as a rolling surface, a fine structure layer that is formed of an acicular structure formed in the outermost surface by melting and re-solidification treatment and that has a thickness of more than or equal to 5 mm and less than 9 mm in depth. In the titanium cast product for hot rolling according to the present invention, the surface is flat, the number of minute voids in the interior immediately below the surface is small, and the outermost surface has a significantly fine structure. When the titanium cast product is subjected to hot rolling, the occurrence of concavities on the surface in the early stage of hot rolling and the occurrence of surface defects on the hot rolled sheet can be stably prevented at a practical level.

Titanium cast product for hot rolling having excellent surface properties after hot rolling even when slabbing step and finishing step are omitted, and method for producing same

Provided is a titanium cast product made of commercially pure titanium, the titanium cast product being produced by electron-beam remelting or plasma arc melting, comprising: a melted and resolidified layer in a range of 1 mm or more in depth at a surface serving as a surface to be rolled, the melted and resolidified layer being obtained by adding one or more kinds of &#x3b2;stabilizer elements to the surface and melting and resolidifying the surface. An average value of &#x3b2; stabilizer element(s) concentration in a range of within 1 mm in depth is higher than &#x3b2;stabilizer element(s) concentration in a base material by, in mass %, equal to or more than 0.08 mass % and equal to or less than 1.50 mass %. As the material containing the &#x3b2; stabilizer element, powder, a chip, wire, or foil is used. As means for melting a surface layer, electron-beam heating and plasma arc heating are used.

Titanium casting product for hot rolling and method for producing the same

A titanium slab for hot rolling comprised of a titanium slab obtain by smelting commercially pure titanium, wherein even if the breakdown process is omitted, the strip shaped coil after hot rolling is excellent in surface properties and a method of smelting that titanium slab are provided. The titanium slab according to the present invention is a titanium slab for hot rolling obtained by smelting commercially pure titanium including the &#x3b2; phase stabilizing element Fe, wherein the formation of coarse &#x3b2; phases is suppressed by making the average Fe concentration down to 10 mm from the surface layer of the surface which corresponds to at least the rolling surface of the titanium slab 0.01 mass % or less. A titanium slab obtained by smelting commercially pure titanium can be obtained by cooling until the surface becomes the &#x3b2; transformation point or less, then reheating it to the &#x3b2; transformation point or more, and gradually cooling from the slab surface layer.

Titanium slab for hot rolling use and method of production of same

There is provided a titanium cast product for hot rolling composed of commercially pure titanium, the titanium cast product including: a microstructural refinement layer having acicular microstructure on an outermost layer of a surface layer to be rolled; and an inside microstructural refinement layer having acicular microstructure provided in an inside of the microstructural refinement layer. Cast solidification microstructure is present more inward than the inside microstructural refinement layer. The microstructural refinement layer has finer microstructure than the inside microstructural refinement layer. The microstructural refinement layer is present in a range of a depth of 1 mm or more and less than 6 mm from the surface. The inside microstructural refinement layer is present in an inside of the microstructural refinement layer in a range of a depth of 3 mm or more and 20 mm or less from the surface.

Titanium cast product for hot rolling and method for manufacturing same

The present invention provides a titanium slab for hot rolling which can be fed into a general purpose hot-rolling mill for producing strip coil, without passage through a breakdown process such as blooming or a straightening process, and can further suppress surface defect occurrence of the hot-rolled strip coil, and a method of producing and a method of rolling the same, characterized in that in the cast titanium slab an angle &#x3b8; formed by the crystal growth direction (solidification direction) from the surface layer toward the interior and a direction parallel to the slab casting direction (longitudinal direction) is 45 to 90&#xb0;, and moreover, there is a surface layer structure of 10 mm or greater whose &#x3b8; is 70 to 90&#xb0;, and further characterized in that a crystal grain layer of 10 mm or greater is formed whose C-axis direction inclination of a titanium &#x3b1; phase is, as viewed from the side of the slab to be hot rolled, in the range of 35 to 90&#xb0; from the normal direction of the surface to be hot rolled. The titanium slab concerned is produced using an electron beam melting furnace by casting at an extraction rate of 1.0 cm/min or greater.

Titanium slab for hot rolling, and method of producing and method of rolling the same

A method of production of an &#x3b1;+&#x3b2;-type titanium alloy part for a motorcycle, car, or bicycle which has a high Young's modulus (rigidity) in the axial direction of the shaped product and a bolt, engine valve, or connecting rod made of an &#x3b1;+&#x3b2;-type titanium alloy and a method of production of the same, wherein an &#x3b1;+&#x3b2;-type titanium alloy is heated at the temperatures giving the &#x3b2;-single phase, then is uni-directionally hot rolled, the plate is machined so that a direction vertical to both the hot rolling direction and thickness direction (width direction) corresponds to the direction in which high rigidity is demanded in the finished part, that is, the axial direction of the bolt, engine valve, or connecting rod, and the X-ray diffraction intensities I(0002), I(10-10), and I(10-11), of the (0002) plane, (10-10) plane, and (10-11) plane of the titanium &#x3b1;-phase measured at the cross-sections vertical to the longitudinal axial direction of the parts satisfy I(0002)/[I(10-10)+I(10-11)]&#x2267;1.

&#x3b1;+beta-type titanium alloy part and method of production of same

The present invention provides a titanium material for hot rolling which enables reduction of defects on the surface (in the case of a flat material or strip coil, including not only the flat surfaces but also the side surfaces and edges) due to hot rolling. The titanium material for hot rolling has dimples imparted by cold plastic deformation whose mean value of the heights (Wc) of the undulation profile elements is 0.2 to 1.5 mm and mean value of the lengths (WSm) thereof is 3 to 15 mm. The invention also provides a method of producing the titanium material and a method of hot rolling the titanium material.

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Tokyo, Japan

Tomonori Kunieda