JPS59110786A - Method for descaling steel stock and apparatus therefor - Google Patents

Abstract

PURPOSE:To suppress excessive lowering of the temperature of steel stock so as to perform uniform descaling, by moving a spray nozzle for descaling along the direction of the feed of the steel stock and controlling the relative speed of them. CONSTITUTION:While the steel stock W is fed as shown by an arrow alpha, a high pressure water header 4 is reciprocated as shown by arrows beta, gamma, and turning blades 7 positioned between the high pressure water header 4 and the surface of the steel stock W is rotated in such a manner that when the high pressure water header is moved in the direction as shown by the arrow beta, a window 8 is open to the spray nozzle, but when the high pressure water header is moved in the direction as shown by the arrow gamma, the window 8 is turned. Therefore, during the course as shown by the arrow beta, the descaling is in operation, but during the course as shown by the arrow gamma the descaling is not in operation because the jetted water stream from the spray nozzle is cut by the turning blades 7, so that excessive lowering of the temperature of the steel stock W can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical field to which the invention relates) The present invention relates to a method and apparatus for descaling steel materials, and in particular, uses a high-pressure water jet as usual, but suppresses the temperature drop of the steel material as much as possible. In addition, we have developed a process and device that advantageously removes scale from the surface of steel by utilizing effective water collision energy and thermal stress caused by cooling.0 (Problems with conventional descaling technology) In conventional descaling devices, for example, Fig. 1 (a), (t))
As shown in Fig. 1, a spray nozzle 2 attached to a high-pressure water header 1, which is fixedly constructed surrounding the steel material to be descaled, continuously sprays a water stream 8 under high pressure while the steel material W is passing through. In such a device, the supply pressure of the jet water stream 8 and the capacity of the spray nozzle 2 are adjusted to match the steel material W to be descaled. Although it is necessary to design such that sufficient descaling performance can be ensured over the entire variation range of the cross-sectional area or feed rate, in practice, it is difficult to perform appropriate control over the entire variation range. For this reason, even though descaling performance was ensured depending on the conditions, the temperature of the material was often lowered more than necessary, which often resulted in loss of heating fuel and rolling power. Although it is possible to make adjustments such as replacing 2 with one of a different capacity or reducing the number of pieces used by blocking the nozzle hole, there is no control that follows this even if the rolling speed changes within the same rolling chance. It is clear that this is completely impossible, and therefore, the temperature reduction of the steel material W which has been lowered in rolling capacity will be undesirably accelerated.

In this respect, the maximum heating temperature is often limited due to decarburization regulations, especially when the cross-sectional area of the steel material W is small, such as in wire rod rolling. The power required for rolling increases, and in some cases, descaling cannot be carried out because rolling becomes impossible. Problems like the above are, for example, when the descaling device is placed close to the rolling mill, and the rolling speed is reduced. Although this is a problem when descaling can only be performed under conditions that are constrained by OBJECT OF THE INVENTION) The purpose of the present invention is to solve the above-mentioned problems by making it possible to perform descaling under optimal conditions regardless of the rolling speed and other feed speeds of the steel material, and to reduce the temperature of the steel material by doing so. We have developed an effective means to advantageously suppress undesirable excessive deterioration.
This provides a very important problem solution in the present day when customer demands regarding surface properties etc. are becoming extremely strict. (Structure of the invention) The idea of this invention is to The idea is that by moving the spray nozzles and controlling their relative speeds, it is possible to adjust the optimal conditions for descaling without overcooling.

This invention provides a method for descaling the surface of a steel material by sweeping the surface of the steel material using a water jet under high pressure during hot rolling, etc., by reciprocating the spray nozzle of the water jet along the feeding direction of the steel material. In the row (4) in the direction opposite to the feed of the steel material, the water jet under high pressure is released toward the surface of the steel material, and in the return process, the water jet is directed toward the surface of the steel material at a moving speed that exceeds the feed speed of the steel material. The above idea has been put into practice by controlling the release and suppressing the excessive drop in the temperature of the steel material.In particular, the release of the water jet during the return stroke is cut off between the spray nozzle and the surface of the steel material. This is further realized by the rotation of the baffle plate around the axis of the steel material, and is equipped with a spray nozzle for a water jet under high pressure that opens toward the operating surface to descale the steel material, and the direction of feed of the steel material is controlled. A device that combines a high-pressure water header constructed so as to be movable back and forth along the surface of the steel material with a deflector plate that diverts the jet water flow away from the surface of the steel material during the return stroke of the reciprocating movement of the high-pressure water header between the surface of the steel material and the spray nozzle; is a rotating cylinder whose baffle plate has an elongated window opening facing the spray nozzle, and the window can be turned around the axis of the steel material during the return stroke of the high-pressure water header. Hereinafter, a specific example in which the present invention is applied to descaling a square bar will be described in detail.

Figures 2 (a) and (b) show the configuration of the main parts, in which 4 is a high-pressure water header, 5 is a spray nozzle, 6 is a water jet, 7 is a deflection plate, and 8 is a long and narrow window in the vertical direction. It is a hole.

The high pressure water header 4 is reciprocated as shown by the arrows β and r while the steel material W is fed and moved as shown in the arrow α shown in FIG. The deflector plate 7 located in the direction of the window hole 8 of the high pressure water header is
The window hole 8 is opened facing the spray nozzle, but in the return stroke indicated by the arrow r, the window hole 8 is rotated or rotated so as to turn around.

Therefore, in the forward stroke β, the descaling operation is in progress, and in the return stroke r, the descaling is not in operation, in which the water flow jetted from the spray nozzle is blocked by the deflection plate 7.

In this example, for a rectangular bar-shaped steel material W with a square cross section, the high-pressure water header 4 for descaling is provided with spray nozzles 5 at four locations around the steel material W, as shown in Fig. 1. . The reciprocating range of the high-pressure water header 4 is wider than the length l of the window hole 8 in which the spray nozzle 5 faces the surface of the steel material W through the window hole 8 of the deflection plate 7 during its forward stroke β. Of course, the width W of the window hole 8 is set to be larger than the bundle diameter of the water stream 6 jetted by the spray nozzle 5 (1).

Therefore, during the movement of the high-pressure water header 4 and thus the spray nozzle 5 in the forward step β, while the jet water flow 6 from the spray nozzle 5 is applied to the four sides of the steel material W, the jet water flow 6 is maintained at a constant flow rate of the top speed, and of course is accelerated and decelerated. Water is sprayed with a margin that allows for control, and at this time, the relative speed r of the bundle of jetted water streams 6 to the surface of the steel material W is equal to the feed rate U of the steel material W and the moving speed V of the toss flare nozzle 5. Therefore, by adjusting this moving speed V according to the feed speed Uvc, the relative speed +17, which is necessary for descaling, can be controlled to minimize the temperature drop of the steel material W, and this It is clear that the scaling extends over the length region of the surface of the rope W that corresponds to the length l of the window hole 8 of the baffle plate 7, and therefore the return stroke movement speed of the rudder 4 to the high-pressure water (7) is Uniform descaling in the length direction of the waste material W can be achieved by setting the reversal after reaching the stroke end, that is, the start of the re-stroke to coincide with the previous descaling end point.

The baffle plate 7, which is cylindrical in the illustrated example, is pivoted or rotated so as to turn its window hole 8 into a position where it is in conflict with the water jet 6 during the return stroke of the high-pressure water header 4. 90° in this example, indicated by the arrow δ in figure (a)
It is preferable to link each thrust with the return stroke movement of the high-pressure water header 4. Of course, if a similar relative position can be achieved, the baffle plate 7 can be rotated, for example, by a 45° oscillation. It may also be a manual operation.

In any case, it is clear that the moving speed of the high-pressure water header 4 can be operated automatically without having to adjust it each time, for example by building a circuit that processes and controls the roll rotation speed signal of a rolling mill. Some 0 In the above-mentioned example, a cylindrical baffle plate 7 is used (8
) ・As shown in the case, if the function of deflecting the jet water flow toward the steel surface on the return stroke without interfering with the descaling operation during the forward stroke of the high-pressure water header's reciprocating movement is satisfied, the structural work conditions will be as described above. There is no need to be particular about the location; for example, it may be the opening/closing operation of a solenoid valve with excellent responsiveness.Also, from the point of view of operability, we will explain the case where a spray nozzle is attached to a high-pressure water header and moved forward and backward together. However, by connecting the spray nozzle to a fixed high-pressure water header using flexible piping,
It goes without saying that the present invention can be applied not only to a bar with a square cross section, but also to a round bar or a steel plate. According to the invention, uniform descaling of the steel material surface is possible while effectively reducing the accompanying excessive decrease in the steel material temperature, and the disadvantages resulting from the excessive decrease in the steel material temperature during rolling and other operations following descaling can be achieved. Moreover, according to the apparatus of the present invention, it can be directly used to carry out a descaling method that can advantageously suppress the steel material temperature drop to appropriately achieve the purpose.

[Brief explanation of the drawing]

Figures 1 (a) and t) are front and side views illustrating a conventional descaling device, and Figures 2 (a) and (b) are sectional views and side views illustrating the descaling procedure according to the present invention. Figure 8 is a diagram showing the operating cycle of the descaling process. W... [t 5-point spray nozzle 6.
... Water jet 7 ... Deflector plate 8 ... Window hole〇(11) (a) Fig. 1 < 1)) Fig. 3

Claims (1)

[Claims] L: For descaling the surface of a steel material by creepage sweeping using a water jet under high pressure during hot rolling of the steel material. The spray nozzle of the water stream is moved back and forth along the direction of feed of the steel material, and in the stroke opposite to the direction of feed of the steel material, a water jet under high pressure is emitted toward the surface of the steel material, and in the return process, the feed rate of the steel material is adjusted. A method for descaling steel materials, which is characterized in that it controls the discharge of jet water toward the surface of the steel material at a moving speed exceeding 100 kW, thereby suppressing excessive changes in the temperature of the steel material. 2 The release of the jet water flow during the return stroke is interrupted by a souffle.
2. The method according to 1, by rotating a baffle plate between the nozzle and the surface of the steel material about the axis of the steel material. & A high aqua regia header is equipped with a spray nozzle for ejecting water under high pressure that opens toward the surface of the steel material to be descaled, and is installed so that it can move back and forth along the direction of feed of the steel material. A steel descaling device consisting of a deflector plate that diverts the jet water flow away from the steel surface during the return process of the reciprocating movement of high-pressure water between the steel plate and the steel plate. 4. The device according to claim 3, which is a rotatable cylinder having a hole and capable of turning the window hole around the axis of the steel material during the return stroke of the high-pressure water header.