JPS609515A - Descaling method of hot rolled steel sheet - Google Patents

Abstract

PURPOSE:To perform descaling efficiently at a low cost by bending a hot steel sheet in running to provide a shearing force to the scales on its surface and rubbing the sheets together. CONSTITUTION:A hot steel sheet 5 is passed through wrapping rolls 2, 3 in the arrow direction after passing a deflector roll 1 and is delivered from a deflector roll 4. The sheet 5 is passed while rubbing under advancing, the surface of sheet 5 returning in the arrow direction after once passing the roll 3, and the surface of the sheet 5 entering from the roll 1 with each other in the mutually reverse directions at the roll 2 to rub off the scales of its surface layer by providing a shearing force to the scales. On the other hand, the sheet 5 is passed while rubbing the under surface of the sheet 5 wntering from the arrow direction, and the under surface of the sheet 5, advancing in the arrow direction with each other at the roll 3 to perform the descaling of the under surfaces. Further, as frictional heat is produced by the mutual contact of sheets 5, cooling water is supplied from a header 7 to cool them.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for mechanically removing scale from a metal strip, typically a hot-rolled steel plate, on which scale has adhered to the surface.

Traditionally, hot-rolled steel sheets have been descaled by chemical removal methods using hydrochloric acid or sulfuric acid, and mechanical removal methods by projecting solid particles (sand, iron sand, etc.) onto the surface with air or high-pressure water. etc. are known.

However, the former method of pickling has problems with acid consumption and requires a fairly long treatment tank to increase the descaling rate, while the latter method of jetting requires a considerable amount of energy, and both require large equipment costs. , maintenance costs and running costs are required.

In addition, in order to increase the descaling efficiency, there are methods of causing cracks in the scale phase in advance, such as a method of bending the copper strip (processor) and a method of shearing the copper strip (Pv mill, etc.). In the latter method (P Mill), it is possible to mechanically remove steel by applying an excessively different circumferential speed, but in this case it is difficult to descale the front and back surfaces in the same way, and It is expected that the lifespan of the rolls used will also be an issue, and both methods basically create cracks in the scale layer to assist in descaling, and there are limits to their effectiveness.
It must be recognized that the problem of acid consumption in pickling still remains.

In view of these circumstances, the present invention provides a mechanical removal method with relatively low cost and high descaling ability. That is, the gist of the descaling method of the present invention is to achieve the purpose of descaling by rubbing the surfaces of steel plates together and mechanically peeling off the scale layer.

The present invention will be specifically described below based on embodiments shown in the drawings.

FIG. 1 shows an example of a roll arrangement for continuously descaling both sides of steel and plate. First, 2.3 is a winding roll, which rotates in opposite directions.

Reference numerals 1.4 denote an entry deflector roll and an exit deflector roll that guide and support the steel plate 5, respectively.

After passing through the entrance deflector roll 2 as shown in the figure, the steel plate 5 advances in sequence according to the arrows and reaches the exit deflector roll 4'. In the figure, 6 is a guide roll for preventing coil walking, and 7 is a header for supplying cooling water between the steel plates.

Therefore, in the aforementioned direction IC progressing roll 2, the surface of the steel plate coming in from roll 1 (the face plate - F side is the front surface and the bottom surface is the back surface) and once the roll 3? : The surfaces of the steel that have passed through and returned as shown by the arrows rub against each other in opposite directions, applying shearing force to the scale on the surface layer and causing it to fall off. On the other hand, in the roll 3, the back surface of the steel plate coming in from the direction of the arrow and the back surface of the steel sheet advancing from the direction of the arrow pass through contact in the same manner, and descaling is performed.

In this case, frictional heat is generated due to the contact between the steel plates, so
It is cooled by cooling water from the water supply header 7.

That is, this water supply header 7 is intended to have a cooling effect on the steel plate, a uniform polishing effect, etc., but methods have also been proposed in which the entire head is submerged in water instead of using a nozzle, and methods in which acid or the like is used instead of water. Ru.

In addition, in the post-process of this device, we expect more uniform descaling by using conventional pickling and mechanical descaling methods, and by using a processor or Pmill in the pre-process, efficiency will be increased. You can also expect things like that.

The method for realizing the present invention is not limited to the roll arrangement as described above, but any method (for example, horizontal type) in which the front and back surfaces of the steel plate are rubbed against each other, or using a fluid pad without using rolls, A method of supporting a steel plate as a fluid bearing may also be used.

[Brief explanation of the drawing]

FIG. 1 shows a front view of an apparatus for implementing the present invention, and FIG. 2 shows a side view of FIG. 1. In the figure, 1.4... - deflector roll, 2.3... winding roll, 5... steel plate, 6... guide roll,
7... Cooling water supply header. Representative Patent Attorney Tomoyuki Yabuki and one other person Figure 1 Figure 2a

Claims (1)

[Claims] A method for descaling a hot-rolled steel plate, which comprises bending the hot-rolled steel plate into a flat plate to apply shearing force to the scale on the surface, and rubbing the steel plates against each other.