Nippon Steel Corporation

Other

Seishiro Yoshiwara

Takao Kawanami

Minoru Kawaharada

Samon Yanagimoto

Hirokichi Higashiyama

Susumu Mizunuma

Kenichi Suzuki

Yukihiro Kako

Motoaki Sugiyama

Mitsuo Kanda

In a method for producing a clad plate by rolling an improvement comprises: a base material, a cladding material, and a cover material overlaid one on another to form a multi-layer structure, and after cleaning joining surfaces of the materials, the cover material is welded to the base material along the periphery thereof, thereby sealing and fixing the cladding material between the cover material and base material, and forming a multi-layer assembly. A member for preventing warp is overlaid over an outer surface of the cover material via a separating agent, and the member for preventing warp and the base material are fixed to one another by welding along the periphery thereof, thereby forming a blank for rolling. The blank is hot-rolled, a rolled article is cut along its periphery to separate the means for preventing warp, and subsequently, the cover material is removed by machining, grinding, or pickling.

Method for producing a clad plate by hot rolling

The surface of a base metal is alloyed with the aid of a laser or electron beam which locally melts the surface. During the alloying, defects are prevented from occurring due to the use of an deoxidizing agent and a low-melting-point metal having a lower melting point than than of the base metal.

Method for surface-alloying metal with a high-density energy beam and an

A method for producing a clad plate by rolling a cladding assembly formed of a cladding material and a base material to bond the cladding material with the base material. The bonding is effected by main rolling initiated at an essentially central portion of a predetermined bonding surface of the cladding assembly and is advanced toward one of the ends of the cladding assembly.

Method for producing a clad plate by rolling

An apparatus and method for forming a cylindrical metal product. A housing having a housing axis therethrough aligned with a mill center line has a gear disposed therein having both sides rotatably supported in the housing for rotation about the housing axis. The gear has a tool holding opening therein the axis of which is offset from the mill center line, and is driven by a pinion. A ring-shaped tool is slidably rotatably fitted in the tool holding opening in the gear and is radially aligned with the gear and has an inner surface which circularly turns the outer surface of a metal workpiece to be formed into the cylindrical metal produce upon rotation of the gear. The metal workpiece is moved through the housing along the housing axis while being supported by supporting devices disposed upstream and downstream and closely adjacent the ring-shaped tool in the direction in which the metal workpiece is moved.

Method and apparatus for forming long cylindrical metal products

The present invention is an improvement of such methods as the Stiefel-Mannesman piercing, and the Mannesmann piercing methods with a pair of driven rolls which impart a screw movement to the work piece, and has the roll axis inclined to the centerline of mill. Instead of a conventional pair of driven disc rolls or shoes, one driven disc roll and one shoe or one guide roll are used in the invention to form the rolling pass together with the driven rolls, and the centerline of pass is greatly off set from the centerline of mill toward the one shoe or guide roll. The operating efficiency and quality of tubular products are simultaneously enhanced.

Rotary rolling mill and method for rolling of tubular products

A solid square cross-section bloom or billet is pierced to form a hollow cylindrical piece with a closed end, using a combination of a mandrel carrying a plug or piercing point at its leading end and a set of rolls. The closed-end cylindrical workpiece and the piercing mandrel together, at the completion of piercing, are fed into a rotary elongating mill, with the closed end of the workpiece foremost. Rotary elongation is performed on the workpiece while pushing the mandrel until the plug has at least passed the point at which the closed end of the workpiece clears the delivery end of the elongation rolls.

Method of manufacturing seamless metal pipes and tubes

A tubular blank is continuously rolled into a pipe through a mill which has a plurality of roll sets each comprising grooved driven rolls providing substantially circular passes of progressively reduced diameters. While the blank is passing through the roll sets, its interior is supported by a mandrel. The tail end of the mandrel is held by a pushing device when rolling is started. Namely, rolling is started by pushing the mandrel into the blank. The pushing of the mandrel is stopped between the time when the front end of the blank has passed the last roll center line in the first half roll set group and the time when it has reached before the roll center line of the last roll set. The tail end of the mandrel remains unreleased while rolling is continued. Then, the mandrel is released between the time when the tail end of the workpiece has passed the roll center line of the second last roll stand in the first half roll stand group and the time when it has reached before the roll center line of the last roll stand. After the mandrel has been released, too, the workpiece is continuously rolled through at least one stand. When the mandrel and workpiece have cleared the rolling mill, the mandrel is withdrawn from the workpiece.

Continuous pipe rolling process

A press roll piercing method wherein a polygonal billet is pushed in the axial direction thereof between a pair of driven rolling rolls mounted one above the other and a piercing plug is supported in the center of the pass by a mandrel, is improved by selecting a pushing force of a predetermined value which corresponds to a stress above the yield stress of the billet at the starting of the piercing although the actual stress occurring at the starting of the piercing may or may not exceed the yield stress by selecting the pushing speed and/or the peripheral speed of the rolls such that the volume of the billet pushed in per unit time and the volume of the hollow shell discharged from the rolling rolls become substantially equal, whereby the billet is positively gripped by the rolling rolls.

Press roll piercing method

A method of producing a cylindrical metallic tubular body in a press roll piercing mill. The method involves applying a pressing force to a polygonal metal billet in the axial direction thereof while guiding the billet by means of a guide during its advance, rolling corner portions of the billet to a certain degree with a pair of rolling rolls having semicircular grooves disposed above and below the billet prior to the contacting of a plug with the center of the front end surface of the billet, and successively piercing the billet by means of the plug while the billet is rolled, the tip portion the plug being retained on the pass center line by the rolling rolls.

Method of producing tubular body in a press roll piercing mill

In a method of producing seamless steel tube from billet having a square or rectangular cross-section by the step of piercing a workpiece and rolling steps following the piercing step, each of such steps being conducted with a plug held by a mandrel toward the center of cross section of the workpiece while the workpiece is rolled by a pair of rolls with axes arranged horizontally. The piercing step includes guiding the workpiece by a plurality of pairs of guide rolls provided along the rolling line ahead of the rolling rolls as the billet is forced therethrough to maintain the billet in such a position that the hollow shell will not have any nonuniformity of wall thickness and piercing workpiece with a plug as the workpiece is pushed and inserted between the rolling rolls under the forced guidance by a pushing force working in the axial direction, and as the plug progresses into the center of cross section of the workpiece, so as to pierce the workpiece, thereby producing seamless steel tube having very little nonuniformity of the wall thickness.

Growing community of inventors

Kitakyushu, Japan

Seishiro Yoshiwara