JPS59209491A - Continuous type hot rolling method - Google Patents

Abstract

PURPOSE:To join smoothly and quickly the rear end of a preceding rolled material and the front end of a succeeding rolled material by providing sloped end faces by pressing to said front end and rear end, butting the two end faces on different planes and conducting high frequency current thereto while pressurizing the butt surfaces on the same plane. CONSTITUTION:The rear end of a preceding rolled material 10a and the front end of a succeeding rolled material 10b are pressed on the inlet side of a roughing mill or finishing mill to slope the respective end faces 11 with an angle of inclination theta by about 2-4 deg. relative with the perpendicular plane. The two end faces 11 are then butted and a V-shaped step is provided by a lifting cylinder 44 so that the end faces are butted on different planes. Contact chips 45 are brought into contact with the side faces and high frequency current is conducted thereto to heat a welding point 111. The welding point is pressed by a press contact roll 43 to start joining. The cylinder 44 is thereafter gradually descended and the point 111 is moved successively toward the transverse direction. The roll 43 is moved in follow up to said movement. The preceding and succeeding rolled materials are thus smoothly and quickly joined and rolling efficiency is improved.

Description

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

The conventional hot rolling method is an intermittent rolling method in which heated slabs are supplied 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, it is necessary to take measures such as lowering the rolling speed. Once a problem occurs, it is necessary to stop the line or replace the roll.

Therefore, the downtime of the line increases, leading to an increase in roll consumption.

The leading and trailing ends of the rolled material are more likely to experience temperature drop and thickness deviation due to imbalance in rolling speed than the center. In addition, the width of the tip of the rolled material became narrow immediately after it was bitten by the finishing work roll, and due to the sudden rise in tension when winding the down coiler, and the width of the rolled material became narrower than the specified width. There were some things I couldn't get.

A method has been proposed in which the end portion and the leading end of the subsequent rolled material are overlapped, and the side surfaces thereof are tack welded to join the rolled material and then continuously rolled. However, with this method, the joint part of the rolled material becomes thicker than other parts, which causes rapid load changes to be applied to the next finishing mill, resulting in variations in board thickness. Furthermore, tack bonding has weak bonding strength between parts, leading to frequent rolling troubles.

! - Therefore, an object of the present invention is to provide a continuous hot rolling method that can 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. It's about finding a way.

In the continuous hot rolling method of the present invention, on the entry side of a rough rolling mill or a finishing rolling mill, press forming is performed on the trailing end of the preceding rolled material = lS and the leading end of the trailing rolled material, so that the end faces of both ends are press-formed. The two end portions are made to have an inclination of 2 to 4 degrees with respect to the vertical plane, the two end portions are abutted on different planes, and the abutment surfaces are pressed together on the same plane and joined by high frequency electric resistance welding.

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 FIG. 1, 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 FIG. 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 press forming 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 press forming machine 3, as shown in FIG.
, 1 (Inclination angle θ = 2 to 4 with respect to the plane perpendicular to the end face of M+
It is preferable to have the function of being able to form the inclined surface 11 of °C and move in the running direction in accordance with the traveling speed of the rolled material.

The inclination angle θ is determined in conjunction with the welding process described below.

When the inclination angle θ is 2° or less, welding point 111 (V
(Fig. 5) The end faces of the leading and trailing rolling machines come into contact at the front, the current is short-circuited and that part is heated, and the welding point 111 is no longer heated. If the inclination angle θ is 4° or more, the V-shaped step in the vicinity of the welding point 111 becomes large, and the thermal efficiency deteriorates.

A specific example of the press molding machine 3 is shown in FIG. The press forming machine 3 consists of a clamp part IJ'3] and a press member 32, and the clamp member 3] is a rolled material 10a.

10h, and the press member 32 forms an inclined surface on the end surface.

The welding machine 4 preferably has the function of being capable of welding the entire width of the upper and lower surfaces of the end portion of the rolled material at high speed, and of being able to move in the traveling direction in accordance with the traveling speed of the rolled material. As such a welding machine 4, for example, a high frequency resistance welding machine is suitable.

Since this welding machine reduces the welding time, it is possible to prevent the temperature of the rolled material from dropping, and it can adequately respond to the advancing speed of the rolled material.

A specific example of the welding machine 4 is not shown in FIGS. 4 and 5.

It is made up of a welding machine 4, a cart 41, a high frequency power source 42, a contact tip 45, a pressure roll 43, and a push-up cylinder/1/I. Cart/II moves along the direction of movement of the rolled material. The high frequency power source 42 is fixed to the trolley 41. The contact tip 45 is brought into contact with the rolled material and supplies a high frequency current. The pressure roll 43 is suspended on a platform J4 so as to be able to swing freely, and can run in the width direction of the rolled material. A push-up cylinder 44 is fixed to the carriage 41 and pushes one end of the rolled material (FIG. 5) to define a V-shaped step necessary for resistance welding.

For example, as shown in FIG. 5, when the inclined surface 11 is inclined toward the upstream side in the traveling direction of the rolled material, the rear end of the preceding rolled material 10α and the end of welding are pressed into the push-up cylinder 44.
to define a V-shaped step in the width direction at the joint between the dynamically rolled materials 10a and 10h.

It is preferable to provide a normal flying crop shear 5 between the rough rolling mill 2 and the press forming machine 3. This shear 5 is provided to cut a crop from the end of the rolled material and align the butt surfaces. If the abutting surfaces are aligned from the beginning, the shear 5 is not necessary.

Next, the steps of the method of the present invention will be explained with reference to FIGS. 1 to 5. As shown in FIG. 1, first, a flying crop shear 5 is used to cut the front and rear ends of the rolled material. Next, as shown in Fig. 3, a tilted screw 1'' of a predetermined shape is formed on the entire width of the upper and lower surfaces of the rear wheel portion of the pre-rolled part 10a using the press forming machine 3.Subsequently, in the same manner As shown in Fig. 6, the press forming machine 3
A slope J1 of a predetermined shape is formed by forming the slope J1.

℃ in the welding machine 4, the rear end of OaO and the tip of the trailing rolled material 0/I are butted against each other, and a V-shaped step is formed on the abutting surfaces by the push-up cylinder 44. , and bring the contact tip 45 into contact with the side surface (welding completed☆iAi (I411)) of both rolling mills IQa, , ]Ob,
Heat the welding point 11 by passing a high frequency current,
The welding point is pressed by a pressure roll 43 to join. During welding, the push-up cylinder lI/l is gradually lowered and the welding point is sequentially moved in the width direction, and the pressure welding roll 4
3 is also moved following the movement of the welding point 111. In this manner, the preceding rolled material Oα and the subsequent rolled material IQ/+ are joined in the same plane by high frequency electric resistance welding.

By sequentially repeating the following steps, rolling) l)
J are joined one after another and hot rolled continuously.

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

Two slabs extracted from the heating furnace (thickness 270 mm
width], 550 mm) to a thickness of 30 mm by a rough rolling mill consisting of 6 stands on a normal continuous hot rolling line.
mm x width] -500+urO rough rolled material. Then,
Between the Hu rolling mill and the finishing rolling mill, among the rough rolled materials, the rear end of the preceding rolled material and the tip of the trailing rolled material ☆j1
11 parts were press-molded into the shape shown in Fig. 2.The inclination angle θ of the end face was set to 3°.

Next, the table rollers were controlled to connect the tip of the trailing rolled material to the tip of the preceding rolling material, and high frequency electric resistance welding was performed. The welding speed at this time was 300 m+rr 7 seconds, the frequency was 300 kHz, and the pressing force was 8 ky.
, /cη), the bearing capacity of the rolled material is 100mm
As the welding point moved, the lifting amount was gradually decreased to maintain the V angle of the welding point constant.

In this way, after joining the preceding rolled material and the succeeding rolled material on the same plane, a finishing mill is used as usual to reduce the thickness to 2711 mm.
It was possible to complete hot rolling continuously into a copper strip measuring m x width 1500 mm.

The effects of the method of the present invention are listed below.

B. Loss between the end of rolling and the next rolling of the material for 11 rows.
You will save time and your productivity will improve dramatically.

The downtime will be reduced due to the rolling machine and down coiler curvature problems caused by the AW section of the rolling machine and the reduction in the number of narrowing troubles.

C. It is possible to reduce roll defects and improve productivity, roll consumption rate, and energy consumption rate.

2. A plate η where the tip of the rolling part or the 1"M part is the same as the middle part,
Inno f
IZ to effectively utilize parts of rice that were undervalued or defective.
The yield can be improved.

Ho. The operator's fine adjustment to prevent troubles in the plate threading section 8 and 111 and the visual work in 111 are greatly reduced, making it possible to save the labor of the conventional rolling mill operator.

To ensure the rolling temperature of the front and rear D: A: parts, the finish thickness is 2.0 mu to improve plate passing properties and descaling properties.
4. The burning of the invitation can be eliminated i1.

4 [FIG. 1fii f; Figures 21 through 5 are explanatory diagrams of the apparatus and steps for carrying out the method of the present invention.

]: Finishing rolling mill 2: Rough rolling mill 3 Nibbles forming tool 4: Welding machine 5: Flying crop shear 10a: Leading rolled material ] Ob: Trailing rolling material Patent 1 "Irishin" Sumitomo Metal Industries, Ltd.' Co Agent Patent attorney Kyozo Yuasa□, 1 (4 others) Figure 2 ρ

Claims (1)

[Claims] On the entry side of the rough rolling mill or finishing rolling mill, press forming the rear end of the preceding rolled material and the leading end of the trailing rolled material so that the end surfaces of both ends are inclined by 2 to 4 degrees with respect to the vertical plane; Continuous hot rolling method 3゜ consisting of abutting the two end portions on different planes, and joining the abutting surfaces by high frequency electric resistance welding while pressing the abutting surfaces on the same plane.