Kawasaki Steel Corporation

Other

Kusakabe Electric & Machinery Co.

Nobuki Tanaka

Takaaki Toyooka

Motoaki Itadani

Yuji Hashimoto

Akira Yorifuji

Koji Sugano

Toshio Ohnishi

Masanori Nishimori

Masahiro Kagawa

Kingo Sawada

Yoshinori Sugie

Osamu Furukimi

Takatoshi Okabe

Saiji Matsuoka

Masahiko Morita

Takaaki Hira

Hiroshi Fujiwara

Shigeharu Ochi

Taro Kanayama

Kazuo Omura

Ryoji Kusakabe

Yoshnori Sugie

Masao Shoji

Sho Inui

Toshio Onishi

Toshiaki Amagasa

Mikio Kodaka

Hiroyuki Matsui

Yasuo Nishida

This invention provides a rolling mill and a rolling-mill train which are compact. Reducers to be coupled with them can be made compact. The inner surfaces of pipes to be rolled with the rolling mill and the rolling-mill train can be prevented from becoming squarish. The rolling mill comprises a plurality of rolls disposed symmetrically around the pathline of the rolling mill, an annular driving bevel gear of a large diameter for driving and rotating the rolls, an input-shaft mechanism for rotating the driving bevel gear, a plurality of transmission mechanisms disposed at regular intervals along the driving bevel gear, and a housing for holding them. The input-shaft mechanism (i) has an input shaft inserted in the housing from its outside and an input bevel gear of a small diameter mounted on the input shaft and engaging with the driving bevel gear and (ii) is disposed between two adjacent transmission mechanisms. With the input shaft disposed horizontally, the phase angle of the roll unit can be adjusted minutely.

Rolling mill and rolling-mill train

A method and apparatus for smoothing a thick walled portion of a steel pipe produced by pressure-welding two opposite longitudinal edges of an open pipe with a squeeze roll after being subjected to induction heating. Outer and inner reduction rollers pressure sandwiches the thick walled portion from the outer and inner surfaces of the pipe, a support supports the inner reduction roller to be rotatable and containing a water passage for cooling water, a connecting rod connects the support device to a coupler and contains a further water passage for feeding cooling water to the water passage, and an anchor holds the connecting rod. In the method of producing steel pipes two opposite longitudinal edges of the open pipe are preformed before being subjected to the induction heating and thereafter a thick walled portion is smoothed by the above-described.

Method for smoothing steel pipe seam portion

The steel pipe has a structure composed mainly of ferrite or ferrite plus pearlite or ferrite plus cementite. The steel pipe is characterized by grain size not greater than 3 &mgr;m, preferably not greater than 1 &mgr;m, elongation greater than 20%, tensile strength (TS:MPa) and elongation (E1:%) whose product is greater than 10000, and percent ductile fracture greater than 95%, preferably 100%, measured by Charpy impact test on an actual pipe at &minus;100&deg; C. The structure is characterized by C: 0.005-0.03%, Si: 0.01-3.0%, Mn: 0.01-2.0%, and Al: 0.001-0.10% on a weight basis, and is composed of ferrite or ferrite and a secondary phase, with ferrite grains being not greater than 3 &mgr;m and the secondary phase having an areal ratio not more than 30%. A steel pipe stock having the above-mentioned composition is heated at a temperature of (Ac,&plus;50&deg; C.) to 400&deg; C. and subsequently reduced at a rolling temperature of (Ac,&plus;50&deg; C.) to 400&deg; C. such that the cumulative reduction of diameter is greater than 20%. The reducing is preferably performed such that at least one of rolling passes reduces the diameter by more than 6% per pass. The steel pipe will have high ductility and high strength and will be superior in toughness and stress corrosion cracking resistance, if the content of C, Si, Mn, and other alloying elements is limited low and reducing is performed at the temperature specified above. The resulting steel pipe has good fatigue resistance and is suitable for use as line pipe.

Steel pipe having high ductility and high strength and process for production thereof

A steel pipe containing fine ferrite crystal grains, which has excellent toughness and ductility and good ductility-strength balance as well as superior collision impact resistance, and a method for producing the same are provided. A steel pipe containing super-fine crystal grains can be produced by heating a base steel pipe having ferrite grains with an average crystal diameter of di (&mgr;m), in which C, Si, Mn and Al are limited within proper ranges, and if necessary, Cu, Ni, Cr and Mo, or Nb, Ti, V, B, etc. are further added, at not higher than the Ac,transformation point, and applying reducing at an average rolling temperature of &thgr;m (&deg;C.) and a total reduction ration Tred (%) within s temperature range of from 400 to Ac,transformation point, with di, &thgr;m and Tred being in a relation satisfying a prescribed equation.

Ultrafine-grain steel pipe and process for manufacturing the same

A method and apparatus for smoothing a thick walled portion of a steel pipe produced by pressure-welding two opposite longitudinal edges of an open pipe with a squeeze roll after being subjected to induction heating. Outer and inner reduction rollers pressure sandwiches the thick walled portion from the outer and inner surfaces of the pipe, a support supports the inner reduction roller to be rotatable and containing a water passage for cooling water, a connecting rod connects the support device to a coupler and contains a further water passage for feeding cooling water to the water passage, and an anchor holds the connecting rod. In the a method of producing steel pipes two opposite longitudinal edges of the open pipe are preformed before being subjected to the induction heating and thereafter a thick walled portion is smoothed by the above-described apparatus.

Apparatus and method for smoothing a welded seam of steel pipe

A forming stand for continuously forming a skelp material into a pipe, by pressure of spaced-apart forming rolls supported by spaced upper and lower shafts, the forming rolls having two portions, with one portion fixedly fitted on one side of its shaft, a sleeve slidably fitted to the other end of the shaft and fixedly secured to the sleeve and slidable with respect to the shaft; a bearing box for supporting one side of the associated shaft; a bearing box supporting the other side of the associated shaft through the sleeve; upper and lower stand supporting frames for supporting both of the bearing boxes to be movable in an axial direction; and supporting columns for supporting the stand supporting frames; the pipe-forming force is continuously measured and the forming operation is adjusted such that the measured value of pipe-forming force does not exceed a predetermined pipe-forming upper limit.

Pipe forming roll apparatus and method

A rolling mill comprising a roll unit and a drive unit for driving the roll unit. The drive unit comprises an outer housing, a pair of large-diameter ring-like driving bevel gears disposed concentric with the pass line, an input shaft mechanism for rotating the driving bevel gears, and transmission mechanisms for transmitting the torque of the driving bevel bears to the rolls. Each transmission mechanism comprises a small-diameter transmission bevel gear caught between and engaging with the driving bevel gears and first and second transmission shafts for transmitting the torque of the transmission bevel gear to a roll. The drive and roll units are coupled and uncoupled by couplings. Four positioning parts are formed on the outer periphery of the inner housing of the roll unit. The outer housing of the drive unit is generally in the shape of a ring, and four positioning parts are formed on the inner periphery of the outer housing. When the inner housing is fitted into the outer housing, the inner housing is positioned in the outer housing by the positioning parts laterally and longitudinally and also in both directions of the pass line by stoppers and hold-downs.

Rolling mill

Method of preparing a steel pipe, an apparatus thereof and a steel pipe

A method of producing steel pipes is provided which comprises the steps of providing a steel strip, processing the steel strip into a preheated open pipe, preheating the open pipe at its two opposite longitudinal edges at a temperature higher than about the Curie point, heating the open pipe at the two opposite edges at a temperature higher than about 1,300.degree. C. but lower than the melting point of the steel strip, pressure welding the resultant open pipe with a squeeze roll to thereby form a steel pipe, smoothing the steel pipe at its thick-walled portion formed on an outer surface of the welded seam, and subsequently cutting or winding the resulting steel pipe. An apparatus adapted to form the steel pipes is also provided.

Method of and apparatus for producing steel pipes

Growing community of inventors

Aichi, Japan

Nobuki Tanaka