Hitachi, Ltd.

Teruo Sekiya

Tomoaki Kimura

Toshiyuki Kajiwara

Kazuo Kobayashi

Yoshio Takakura

Masahiro Hayashi

Tadashi Nishino

Yasutsugu Yoshimura

Ryohei Kinose

Makoto Shimizu

Sadao Nishimura

A widthwise bend of an end of a hot-rolled elongate sheet-shaped metal product is corrected while it is hot. The correction comprises simultaneously:

Method and apparatus for correcting a widthwise bend in an end portion

Methods and apparatus for joining conveyed steel pieces in a hot rolling mill are disclosed. A joining apparatus having a series of fusing torches extending laterally across the steel path is used, either before a rough rolling stage or between rough rolling and finish rolling. The fusing torches which operate at the side edges of the pieces to be joined are controlled to have independent movement by a controller, in such a way that the time elapsing between fusing and pressing together of portions at the lateral edges of the join line does not exceed a critical time for regrowth of oxide scale. Various mounting and control techniques for the fusing torches are proposed, including the possibility of two independently-driveable sets the controller can base its control of the torches on steel strip width information obtained from the processing path.

Method and apparatus for joining steel pieces in a hot rolling mill

In this invention, a reversing roughing mill and a reversing finishing mill are disposed at such a distance that a material can reach the finishing mill only in the final pass of roughing, can thus prevent damage to and surface deterioration of finishing rolls in the roughing pass, can reduce the heat loss of the material located between the roughing mill and finishing mill and can produce a strip having excellent surface quality. In the present invention, a continuous casting plant and a hot rolling plant are connected to each other by a furnace having reheating and soaking functions and a heat retaining box for accumulating slabs is disposed adjacent to this furnace. Therefore, even when rolling is stopped due to any trouble with the rolling plant and extraction of the slab from the furnace to the rolling plant cannot be made, the continuous casting plant can continue to cast the slab without stopping its operation and the cast slabs are accumulated in the heat retaining box and the accumulated slabs can be heated by the furnace and can be extracted to the rolling plant before the next pouring by a ladle.

Hot strip plant

In a continuous hot rolling system, at least one melt-cut torch is set in a predetermined positional relationship with respect to a trailing end of a preceding hot material and a leading end of an adjacent succeeding hot material. An injected flow of cutting gas from the melt-cut torch is blown against a portion of at least one of the trailing end of the preceding material and the leading end of the succeeding material to melt-cut the portion. The portion extends from an end surface of the one end over a predetermined length. The trailing end of the preceding material and the leading end of the succeeding material are forced against each other and are butt-joined to each other. By doing so, there are produced joining surfaces superior in surface accuracy and high in temperature, to allow joining to be high in accuracy and strength. This joining may be made with respect to slabs before rough rolling, or may be made with respect to bars after rough rolling. Further, a slab manufactured by a continuous casting machine are reduced in thickness at a plurality of desired locations to form a plurality of thickness-reduced portions. Cutting is made at the thickness-reduced portions. The cut thickness-reduced portions are joined to each other. Furthermore, the ends of the respective materials after having been cut are reduced in thickness with the ends abutted against each other to form thickness-reduced portions. The thickness-reduced portions are joined to each other.

Method of and apparatus for joining hot materials to be rolled to each

When a strip of e.g. hot steel is rolled by a rolling or roughing mill, scale develops on the surface of the strip which must be removed. The strip is passed over a bending roller which bends the strip and causes cracks in the scale. Then water is injected onto the strip to wash the roller and lift of the scale. Inertia then causes the water and scale to leave the surface of the strip and pass to a collection device whose water collecting surface is out of contact with the strip and on the opposite side of the bending roller from where the water is injected. In this way the time of contact of the water with the strip can be kept short and the strip is not damaged by contact with the collection device.

Descaling rolled material

Multihigh rolling mill

Roll driving apparatus for rolling mill

A continuous rolling mill has horizontal roll stands and vertical roll stands disposed alternatingly with rolling guides between the work rolls of adjacent roll stands. The roll stands together with the rolling guides are movable in the direction crossing the rolling line to an exchanging position where the work rolls and the rolling guides are exchanged with new ones. The continuous rolling mill further has a supporting frame supporting the roll stands and movable to the exchanging position thereby to bring the roll stands and rolling guides to the exchanging position, and an offsetting device adapted to move one of the adjacent roll stands relatively to the other of the adjacent roll stands and to the frame in the exchanging position such that the rolling lines of the adjacent roll stands may be offset from each other. This arrangement permits a reduction of the pitch or interval of the roll stands and affords a quick exchange of the rolls and rolling guides with new ones, contributing greatly to the reduction in installation space and cost while improving the efficiency of rate of operation of the rolling mill advantageously.

Continuous rolling mill

A roll changing device for rolling mills, in which the roll are changed through roll exchange between the work roll changing rails and intermediate roll changing rails which are mounted in a housing, and delivery rails placed in front of the rolling mill. The improvement comprises a vertically movable floor device carrying the delivery rails. The vertically movable floor device is adapted to move vertically to bring the delivery roll into alignment with the work roll changing rails and the intermediate roll changing rails to permit an easy and prompt roll change without any restriction in the space, even when the work rolls and the intermediate rolls are mounted at large depths from the floor level.

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Takahagi, Japan

Teruo Sekiya