Hitachi, Ltd.

Sadayoshi Tajima

Yutaka Muramatsu

Tadashi Hashimoto

A hot-rolling equipment installation has a continuous casting apparatus linearly arranged with a simplified heating oven disposed uimmediately after an outlet of the continuous casting apparatus, a sizing press disposed immediately after an outlet of the simplfied heating oven, and rough rolling mills. The sizing press is installed at an inlet side of the rough rolling mills. The slab material is transferred from the continuous casting apparatus to the simplified heating oven and then reduced in width by the sizing press. The simplified heating oven raises the temperature of the edge portions of the slab so that the edge and center portions of the slab are made uniform in temperature. This prevents the edges from cracking during width reduction and subsequent rolling in the rough rolling mills.

Hot-rolling equipment and a method of hot-rolling a slab

In addition to the usual type of screw-down mechanism, work roll gap is adjusted during work roll change for different diameter work rolls, without removing the back up rolls, by a variable height plate rotatably inserted between the back up roll chocks and the housing, which will minimize the volume of oil contained within the screw-down adjustment rams while maintaining good rigidity for the plate adjustment even during high impact and high vibration hot rolling. A similar effect is provided by containing unused plate height portions entirely within the footprint of the housing where they can be rigidly supported. Further rigidity is obtained with minimizing the volume of fluid within the rams, accomplished by placing the valve stand immediately adjacent to the hydraulic rams for the screw-down and preferably on top of the housing. The roll change height adjustment provided by the plates, as opposed to a bulky screw-type adjustment, provides for a reduced height housing and the additional room for the valve stand.

Rolling mill and rolling mill method

A rolling mill has upper and lower work rolls brought into contact with a material to be rolled. An upper backup roll supports the upper work roll, and a hydraulic jack above the upper backup roll adds a pressurizing load adjusted in accordance with a rolling load to the upper work roll via the upper backup roll. The hydraulic jack includes a cylinder arranged such that its bore faces downward and contains therein a slidable ram. A thrust metal block is disposed on an upper surface of the cylinder in a manner which allows it to move between a first position for the rolling work and a second position for exchanging the rolls, the second portion being spaced apart from the first position in an axial direction of the upper backup roll. A pressurizing screw is arranged to abut on an upper surface of the thrust metal when the thrust metal is at the first position, so as to restrict an upward movement of the thrust metal and thereby determine a position of the upper work roll. Further, an actuator is mounted on the cylinder and operatively connected to the thrust metal for moving the thrust metal between the first position and the second position.

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Hitachi, Japan

Sadayoshi Tajima