JPS59137105A - Continuous hot rolling method - Google Patents

Abstract

PURPOSE:To eliminate the defect at the end part of a material and to enable continuous rolling by butting the rear end of a preceding material against the front end of a succeeding one in the same plane and interlocking both ends with clamps for welding the butted surfaces together at the inlet side of a roughing mill or a finishing mill. CONSTITUTION:The rear end part 10a of a preceding material which is passing through a rolling mill 1 is straightly cut by a flying crop shear 5. Successively the front end part 10b of a succeeding material delivered from a mill 2 is straightly cut by the shear 5. The cut parts are butted at each other by a clamp driver 3 by speeding up the succeeding material to drive clamps 31 into the side face parts. The butted parts are successively welded 4 together by a laser beam welder 4. The driver 3 and the welder 4 operate while moving at a speed regulated to conform to that of the sheet material. Further, the thickness of the butted part is sometimes made thin by a press. In this way, the knocking or draw-in, etc. of the end part are prevented, and material yield is improved without producing the cut-off scraps of the sheet material, and continuous rolling is performed.

Description

[Detailed description of the invention] The present invention relates to a continuous hot rolling method.

The conventional hot rolling method is an intermittent rolling method in which heated slabs are fed one by one to a rolling line, and each slab is rolled in a rough rolling mill and then in a finishing mill. With this method, when the rolled material passes through the rolling mill, the leading end of the rolled material may hit the guide or roll, and when the trailing end passes through the rolling mill, it may be narrowed depending on the shape of the trailing end or the rolling conditions. This can cause problems such as roll damage. In order to avoid such troubles, measures such as lowering the rolling speed are required. Once a problem occurs, it is necessary to stop the line and replace the rolls. Therefore, the downtime of the line increases, leading to an increase in roll consumption.

Compared to the center, the front and rear ends of a rolled material are more prone to temperature drop and thickness deviation due to an imbalance in rolling speed, and the center of the width protrudes in the rolling direction and becomes narrower, making it difficult to obtain the desired sheet width. It had been cut off. In addition, the width of the tip of the rolled material becomes narrow due to a sudden rise in tension immediately after it is bitten by the finishing work roll and during winding with a down coiler, and the desired width may not be obtained.

Therefore, in recent years, as a method to solve this problem, the trailing end of the leading rolled material and the leading end of the trailing rolled material are overlapped between the rough rolling mill and the finishing rolling mill, and the sides are temporarily attached or welded. A method has been proposed for making rolled material continuous. but,
With this method, the joints of the rolled material are thicker than other parts, which causes sudden load fluctuations in the next finishing mill.
Variations occur in plate thickness. Furthermore, tack bonding has weak bonding strength between parts, leading to frequent rolling troubles.

Another proposed method is to butt the rear end of the preceding rolled material and the leading end of the trailing rolled material, and then drive a connecting fitting into the side surface of the trailing end to join them.

However, although this method can withstand tensile forces in the rolling direction during rolling, it is weak against forces in the width direction (transverse to the rolling direction) and thickness direction (perpendicular to the rolling direction). If it bends in that direction, breakage will occur.

Therefore, the purpose of the present invention is to advantageously solve these problems, and improve rolling efficiency by smoothly and quickly joining the rear end of the preceding rolled material and the leading end of the trailing rolled material. The object of the present invention is to provide a continuous hot rolling method that can improve product quality and yield.

The continuous hot rolling method of the present invention includes butting the rear end of the preceding rolled material and the leading end of the succeeding rolling material on the same plane on the entry side of a rough rolling mill or a finishing rolling mill; The method consists of driving a filler into the side surface of the rolling stock, and welding the abutting surfaces.In this way, the preceding rolled material and the subsequent rolling material are joined and continuously hot rolled.

Another method of the present invention is to press-form the rear end of the preceding rolled material and the leading end of the trailing rolled material to reduce the thickness, then butt the ends, and then perform the same steps as above. .

In the first and second methods, there is virtually no problem even if the order of the grooving process and the welding process is changed.

Next, the method of the present invention will be explained with reference to the drawings.

The method of the invention is applied to rolled material in a continuous hot rolling line at the entry side of a roughing mill or a finishing mill. In the example shown in FIGS. 1 and 2, the method of the invention is applied to a rolled material on the entry side of a finishing mill 1. In the example shown in FIGS. Here, the entrance side does not mean immediately before the entrance to the rolling mill, but refers to the front a required distance away from the entrance. In the illustrated method of the present invention, a skimming machine 3 and a welding machine 4 are provided from the exit side of the rough rolling mill 2 toward the entry side of the finishing rolling mill 1.

The glazing driving machine 3 may be any device that can drive a groin to the side surface of the abutting portion of the rolled material and can move in the running direction in accordance with the traveling speed of the rolled material. For example, energy from a rammer or gunpowder explosion, or the compressive force of compressed gas, compressed air, etc. can be used. As shown in FIG. 3, the skimmer 31 may be a rectangular steel plate with claws 311 provided at the four corners.

The welding machine 4 may be of any type as long as it can weld the entire width or part of the upper and lower surfaces of the rolled material with a high ripple, and can move in the traveling direction in accordance with the traveling speed of the rolled material. For example, a welding machine using v-the beam is preferable.

Preferably, a conventional flying crop wheel 5 is provided between the roughing mill 2 and the grading mill 3.

This shear 5 cuts a crop from the end of the rolled material,
Provided to align the butt surfaces. If the butt surfaces are aligned from the beginning, the yarn 5 is not necessary.

An apparatus for carrying out another method of the invention is shown in FIG. In this device, a press molding machine 6 is provided between the flying crop shear 5 and the skimming driving machine 3. The press forming machine 6 may be any machine as long as it can form a recessed portion of a predetermined shape over the entire width of the upper and lower surfaces of the rolled material and can move in the running direction in accordance with the traveling speed of the rolled material.

Next, the method of the present invention will be explained with reference to FIGS. 3 to 7. FIG. 3 is an explanatory diagram schematically showing the first method of the present invention, and FIG. 4 is an explanatory diagram of the steps of implementing the method. This first method is carried out by the apparatus shown in FIG. The first method is as shown in FIG. (B) and then weld the abutting surfaces across the entire width or partially from the top and bottom or from either side in the width direction).

The gap 31 strengthens the bonding force of the rolled material in the rolling direction, and the welded portion reinforces the bending strength in the width direction and thickness direction of the abutted portion. Welding does not need to be done entirely in the width direction of the butt surfaces (or it can be done only partially at important points.The key is to weld within a range that provides enough strength to withstand bending stress during rolling). good.

Next, the second method of the present invention will be explained with reference to FIGS. 5 to 7. FIG. 5 is an explanatory diagram schematically showing the second method of the present invention, and FIG. 6 is an explanatory diagram of the steps of implementing the method. This second method is
This is carried out by the apparatus shown in FIG. The second method is
As shown in FIG. 6, first, by the press molding machine 6,
A recess 11 of a predetermined shape is formed over the entire width of the upper and lower surfaces of the leading end of the pre-rolled material 10b (B), and the ends of the rolled material are butted together (C) in the same manner as in the tenth method, and the side surfaces of the butt portion are glazed. 31 (C), and weld the top and bottom of the abutting surfaces in the width direction (D).

The purpose of press forming the ends of the rolled material is that, especially when the thickness of the rolled material exceeds 30 mm, it takes time to weld, which causes a temperature drop in the rolled material, making it difficult to obtain the desired finishing temperature. For this reason, the cross-sectional area of the abutting surfaces of the rolled materials is reduced to shorten the welding time, prevent temperature drop, and accommodate the build-up of the weld bead. however,
If the thickness of the rolled material changes locally, the tension between the rolling stands will change, so it is necessary to determine the thickness reduction formula t (Figure 7) for the rolled material within the range that can be absorbed by the louvers installed between the stands. be.

Next, examples of the method of the present invention will be described.

<Example ■> Two slabs extracted from a heating furnace (thickness 270mm x width 1mm)
300+++m) to a thickness of 30mm and a width of 1mm using a rough rolling mill consisting of 6 stands on a regular continuous hot rolling line.
It was made into a rolled material of 300 mm. Next, the rear end of the preceding rolled material and the leading end of the trailing rolled material of the rolled material are cut by the flying crop shear 5, and the cut ends are butted against each other to determine the speed of the trailing rolled material. Faster than the speed of the preceding rolled material, press the two rolled materials together and butt them together, and use a rammer to drive a glazing 31 with a length of 100 mm, width of 30 mm, and nail length of 20 mm into the butt part using a laser beam welder with an output of 20 mm. The upper and lower abutting surfaces were welded over the entire width for about 60 seconds. During this time, the temperature of the rolled material decreased by about 90°.

By this method, the two rolled materials are completely joined, and the joint part does not bend or shift during the subsequent finish rolling without breaking, etc., and is smoothly rolled into a copper strip with a thickness of 20mm and a width of 1300mm. I was able to do that. The finishing temperature was also able to be maintained at the desired value υ〈Example ■〉 Two slabs similar to those in Example I were used, and after rough rolling they were made into a rolled material with a thickness of 38 mm and a width of 1300 mm, and a press forming machine was used. 6
The rear end of the preceding rolled material and the leading end of the trailing rolled material were rolled down by 40%, and the minimum thickness was reduced to 22.8 mm so as to change smoothly. The ends of each rolled material were cut and aligned using a roller, and the length of the reduced thickness part was 40 mm.
Then, the cut end surfaces were butted on the same plane, and the side surface was pierced with a glazing similar to Example ① and the butt surface was 1000 mm.
After performing width welding and connecting the preceding rolled material and the following rolled material,
Finish rolling was performed. However, in this embodiment, by controlling the variation in rolling tension due to the difference in thickness of the joint by using a hydraulic looper provided between the first stand and the second stand of the finishing rolling mill, the joint can be bent, Thickness 2.5mm without breaking due to misalignment etc. Omrn x width 130
It was possible to continuously complete hot rolling into a 0 nm steel strip.

As is clear from the above explanation, according to the method of the present invention, joining of rolled materials is easy, material yield is improved, productivity is improved by reducing the number of roll changes, and roll consumption rate is reduced. It is possible to achieve energy savings by improving production efficiency and shortening line downtime.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of an apparatus for carrying out the method of the present invention. FIG. 2 is a schematic explanatory diagram of an apparatus for carrying out another method of the present invention. FIG. 3 is a detailed explanatory diagram of the present invention. FIG. 4 is an explanatory diagram of the steps of carrying out the method of the present invention. FIG. 5 is an explanatory diagram of another method of the present invention. FIG. 6 is an explanatory diagram of the process of carrying out another method of the present invention. FIG. 7 is an explanatory diagram of a press-formed portion at the end of the rolled material. 1: Finish rolling mill 2: Rough rolling mill 3; Grasping driving machine 4: Welding machine 5: Flying crop shear 6: Press forming machine 31: Grasping patent applicant
Sumitomo Metal Industries, Ltd. (4 others) Figure 7/θ To lOα 2nd (C) Figure (D)

Claims (2)

[Claims] (1) At the entry side of the rough rolling mill or finishing rolling mill,
Continuous hot rolling, which consists of butting the rear end of the preceding rolled material and the tip of the trailing rolling material on the same plane, driving a filler into the side surface of the butt part, and welding the butted surfaces. Method. (2) At the entry side of the rough rolling mill or finishing rolling mill, the rear end of the preceding rolled material and the tip of the trailing rolled material are press-formed to reduce their thickness; A continuous hot rolling method comprising the steps of butting on the same plane, driving a filler into the side surface of the butt, and welding the butt surfaces.