Nippon Steel Corporation

501 Nippon Steel Corporation

Tsuyoshi Kawano

Hiroaki Masui

Koe Nakajima

Hiroshi Takechi

Hisashi Gondo

Matsuo Usuda

Shiroh Sanagi

Yoshiyuki Ushigami

Katsuro Kuroki

Yasunari Yoshitomi

Kazuo Koyama

Maremizu Ishibashi

Mitsunobu Abe

Tsutomu Haratani

Kunihiko Komiya

Seiji Otomo

Yoshio Hashimoto

Yoshio Nakamura

Shinji Tanimoto

Shoji Nosaka

Toshio Hirokawa

Yukio Matsuo

Kazuo Kovama

Hidenobu Anami

Chikara Fujii

Kaname Hasuka

In the present invention, grain oriented electrical steel sheets provided by heating a slab comprising, by weight percent, 0.025 to 0.075% of C, 3.4 to 5.0% of Si, 0.015 to 0.080% of sol. Al, 0.0030 to 0.013% of N, 0.014% or less of (S+0.405 Se) and 0.05 to 0.8% of Mn, sol. Al (%)/Si (%) being 0.0080 or more, the balance consisting of Fe and unavoidable impurities at a temperature below 1280.degree. C., hot-rolling the heated slab, subjecting the hot-rolled steel sheet to cold rolling, subjecting the cold-rolled steel sheet to decarbonization annealing with regulating the average diameter of primary recrystallized grains of the steel sheet subjected to decarbonization annealing to 18 to 35 .mu.m in a period between the completion of the decarbonization annealing and the initiation of final annealing, coating the decarburized steel with an annealing separator and subjecting the coated steel sheet to final annealing, wherein the final annealing is effected in such a manner that the partial pressure of nitrogen, P .sub.N2 (%), in the annealing atmosphere is 12.5% or more in a steel sheet temperature range of from 900.degree. C. to 1150.degree. C. in the heating stage of the final annealing, and subjecting the steel sheet to nitriding to cause the steel sheet to absorb 0.0010% by weight or more of nitrogen in a period between the completion of the hot rolling and the initiation of secondary recystallization in the final annealing.

Process for production of grain oriented electrical steel sheet having

A non-vent type fully openable easy-opening end has a principal score around the periphery of the end, and a pair of beads which run in a tearing direction. The pair of beads is formed symmetrically at both sides of a tab securing portion of the end which is in the vicinity of the tab securing score. A pair of second beads may also be formed on the periphery of a removable portion of the end which is defined by the principal score in such a manner that they run along the principal score. The second beads are located symmetrically on both sides of the tab securing portion. A straight line l that connects the forward end of the tab securing portion and the starting end of each of the first beads or the starting end of each of the second beads is inclined with respect to the tearing direction at an angle ranging between 45 degrees and 85 degrees. A distance a between the finishing ends of the first beads and the center of the tab securing portion in the tearing direction is equivalent to or larger than the diameter of the tab securing portion and is not less than 4 mm.

Non-vent type fully openable easy-opening end

A stainless clad plate or sheet (herein called sheet) comprising a super-low carbon steel layer containing at least one of Ti and Nb (Ti+Nb.ltoreq.0.15% and ##EQU1## and an austenite stainless steel layer on one or both sides of the carbon steel layer. The thickness of the stainless steel layer is preferably from 2.5 to 30% of the total thickness of the clad steel sheet. The stainless clad steel sheet is produced preferably by continuous casting stainless steel melt on the carbon steel slab, hot and cold rolling the stainless clad steel slab, and annealing under specific conditions for desired properties.

Clad steel materials having excellent ductility and corrosion resistance

A cold rolled boron steel sheet having excellent stretchability, deep drawability, and second workability and method for producing the same, which comprises the steps of hot rolling a steel containing not more than 0.05% C by weight and, P and N in the relation of P+5N.ltoreq.0.0175% by weight at a temperature of 850.degree. C. or more, cold rolling the hot rolled steel strip at a reduction of not less than 50%, and subjecting the cold rolled steel strip to continuous annealing at a temperature between the recrystallization temperature and the A.sub.3 point.

Cold rolled steel sheet having excellent press formability and method

A cold rolled steel sheet having excellent stretchability, deep drawability, and secondary workability, and a method for producing the same, which comprises the steps of hot rolling an Al-killed steel containing not more than 0.0025%N by weight, not more than 0.010%P by weight, and not more than 0.07% C by weight, and wherein P and N have the relation of P+5N.ltoreq.0.02% by weight, at a temperature of 850.degree. C. or more, cold rolling the hot rolled steel strip at a reduction of not less than 50%, and subjecting the cold rolled steel strip to continuous annealing at a temperature between the recrystallization temperature and the A.sub.3 point.

Rolled steel plate is press-fabricated into cylindrical UO pipe with a large wall thickness, by the steps of crimping, U-ing and O-ing. In the U-ing process, a collapsible U-ing punch, including a center block carrying paired side punches on both sides and a bottom punch at the bottom, is used. The U-ing punch insures that the O-shaped workpiece has the desired butt gap by decreasing the ratio of its height to its width when the gap proves to be smaller than the desired butt edge gap, and vice versa when the gap proves to be larger than the desired butt edge gap.

Process for fabricating heavy wall to pipe

Anti-vibration steel materials containing not more than 0.1% of carbon and not more than 0.5% of manganese and having an .alpha. value of not lower than 55, said value being a product of the yield point or stress at 0.2% strain and the grain size number, and a method for producing the same which comprises hot rolling a steel slab, billet or bloom containing not more than 0.1% of carbon, not more than 0.5% of manganese, giving not more than 10% of strain to the hot rolled steel, annealing the hot rolled steel thus strain given at a temperature not lower than its recrystallization temperature but not higher than its A.sub.3 transformation point for at least one minute and controlling the .alpha. value as defined herein to a value not more than 55.

Anti-vibration steel material and a production method therefor

A steel sheet, especially a thin one, can be manufactured from a hot rolled coil through heat treating steps by means of positively applying stress to the material. The product has excellent shape and mechanical properties such as drawability and toughness.

Method and an apparatus for the manufacture of a steel sheet

A hot-rolled steel sheet of high cold formability characterized in that it contains of 0.03-0.30 % C and 0.15-2.0 % Mn as the main ingredients and also by the average length of sulfide inclusions of stringer form and/or silicate inclusions of like form being less than 100 .mu..

Hot-rolled steel sheet of high cold formability and method of producing

A cold rolled steel sheet having excellent cold workability comprising not more than 0.10% of carbon, not more than 0.10% of silicon, not more than 0.50% of manganese, not more than 0.0080% of nitrogen, 0.003-0.080% of acid-soluble aluminum, 0.0020-0.0050% of boron, the balance being iron and unavoidable impurities.

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Kitakyushu, Japan

Tsuyoshi Kawano