JPS6032117Y2 - Continuous spray pickling equipment for strips - Google Patents

Description

[Detailed description of the invention] The present invention aims to improve the settling effect of sludge mixed in an acid aqueous solution and the workability of removing the sludge in continuous spray pickling of strip, and to change the steel type of the strip or the threading speed. The present invention relates to a device that allows quick and appropriate adjustment of pickling strength.

In spray pickling, as the operation progresses, scale from the strip mixes into the acid aqueous solution, and this sludge causes clogging of the spray nozzle. Conventionally, the line has been stopped each time or periodically to remove the sludge. It was being removed.

In addition, the descaling properties of strips, such as stainless steel strips, are determined by the type of steel, such as Cr stainless steel or C
The amount of surface scale differs greatly depending on the type of r-Ni stainless steel, and even for the same steel type, the amount of surface scale varies depending on pretreatment conditions such as annealing and cooling. Since problems such as scale remaining due to insufficient pickling occur, it is necessary to adjust the pickling power, for example, the strip threading speed, depending on the steel type or the amount of surface scale.

However, if a continuous annealing furnace, cooling equipment, etc. are installed in front of the spray pickling equipment, the annealing time, cooling time, etc. Priority is given to the threading speed in the annealing furnace and cooling device.

, Therefore, the sheet passing speed in the subsequent spray pickling device cannot be arbitrarily adjusted.

Therefore, in this case, it is necessary to adjust the pickling power itself.

Conventionally, spray pressure has been adjusted as a means of adjusting spray pickling power itself, but the relationship between spray pressure and descaling effectiveness is not linear as shown in Figure 1; If the spray pressure increases beyond a certain level, the time required for descaling will not decrease commensurate with the increase in spray pressure.

For this reason, it is inefficient, and it is difficult to appropriately adjust the descaling strength, and metacrossing is likely to occur due to insufficient descaling or overpickling.

Other methods of adjusting the concentration or temperature of the acid aqueous solution require time to adjust, so the line must be stopped or a dummy plate must be passed before the adjustment is completed, and the concentration adjustment requires Since the amount of the acid aqueous solution increases, there is a waste of discarding the excess acid aqueous solution.

The object of the present invention is to provide an apparatus that solves such problems in spray pickling.

FIG. 2 shows an embodiment of the apparatus of the present invention, where S is a strip moving in the direction of the arrow, 1 is a cooling device for cooling the strip annealed in a continuous annealing furnace (not shown), and 2 is an acid aqueous solution applied to the strip. The strip S leaves the cooling device 1 and continues in the direction of the arrow in the spray pickling room 2. In the process of passing through, the surface scale is removed by the acid aqueous solution sprayed from the spray nozzle group 3.

4 is a collection tank for collecting the acid aqueous solution after spraying, 7.8 is a storage tank for introducing and storing the acid aqueous solution in the collection tank, and 15 is the collection tank for collecting the acid aqueous solution in the storage tank. A pump for pressure feeding to the spray nozzle group 3 is shown.

The various types are connected by conduits 5 and 11, and a flow path for the acid aqueous solution is formed so that the acid aqueous solution can be circulated and sprayed.

9゜10.12.13 is a switching valve, and each storage tank 7
．． 8 is provided on the entrance and exit sides.

6 indicates a support roller for the strip S.

In this example, a switching valve as a switching means for the acid aqueous solution flow path was provided on the inlet and outlet sides of each storage tank, but if a three-way valve or the like is used as the switching valve, it would be necessary to install it only at each branch point of the conduit. It may be provided.

Next, the operation will be explained.

By switching between the storage tanks 7 and 8, it is possible to settle the sludge mixed in the acid aqueous solution in the tank, and when discharging and removing the sludge, the other storage tank is used during that time. Spray pickling can be continued.

For example, in FIG. 2, it is assumed that the switching valve 9.12 is opened, the switching valve 10.13 is closed, and spray pickling is started using the storage tank 7.

Since the acid aqueous solution in the storage tank 8 is stationary, almost all of the sludge settles after a predetermined period of time.

Therefore, switching valves 9 and 12 are closed and 10.13 is opened to switch from storage tank 7 to 8 for use.

By alternately using the storage tanks in this manner, a pickling aqueous solution containing less sludge can be used at all times.

Additionally, sludge will be drained from unused storage tanks during this period.

In this way, by alternately switching the storage tank, the sludge mixed in the acid aqueous solution in the storage tank that is not being circulated can be left to settle, improving the cleanliness of the acid solution, which is a weak point of spray pickling. It can prevent some sludge from clogging the nozzle.

Furthermore, even if the acid aqueous solution of the same concentration and temperature is stored in each storage tank, if each storage tank is switched and used appropriately, the acid aqueous solution can be left standing, and the sludge in the acid aqueous solution can be effectively sedimented and separated.

The sludge deposited in the storage tank can be removed without stopping the line and relaying spray pickling by draining the acid aqueous solution from the storage tank that is not being circulated and taking out the sludge.

Next, in an embodiment of the present invention, in order to prevent over-pickling or insufficient pickling due to fluctuations in strip threading speed, the concentration or temperature of the acid aqueous solution stored in each of the storage tanks 7 and 8 shown in FIG. Adjust according to the steel type of the strip to be washed and the threading speed.

In this example, the first storage tank 7 stores a high-temperature or high-concentration acid aqueous solution with a strong pickling power, and the second storage tank stores a low-temperature or low-concentration acid aqueous solution with a weak pickling power. has been done.

Now, the strip passing through the spray pickling chamber 2 is of a steel type that is difficult to be descaled, or the strip is thin, and the passing speed in the continuous annealing furnace (not shown) is fast, so the passing speed in the spray pickling chamber 2 is low. If it is fast, switch valve 9,
12 and close the switching valve 10.13.

When the pump 15 is operated, the high temperature or high concentration acid aqueous solution in the first storage tank 7 is forced to the spray nozzle group 3, and is sprayed from the spray nozzle group 3 to form the strip S.
The necessary strong spray pickling treatment is carried out for this purpose.

Contrary to the above, if the strip is a steel type that is easily descaled or the plate is thick and the passing speed in a continuous annealing furnace (not shown) is slow, each switching valve 9, 10, 1
2.13 is set in the opposite manner to the above, and spray pickling is performed using the acid aqueous solution in the second storage tank 8 in which a low temperature or low concentration acid aqueous solution is stored.

In this way, the concentration or temperature of the acid aqueous solution stored in each of the storage tanks 7 and 8 is adjusted according to the steel type to be spray pickled, and the storage tanks can be switched and used depending on the steel type of the strip, the threading speed, etc. By doing this, it is possible to carry out suitable pickling, and by changing the storage tank, it is possible to obtain a sedimentation effect for the sludge.

By providing at least two storage tanks, the pickling power can be adjusted in advance for the next strip to be processed without stopping the line.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows the relationship between descaling time and spray pressure in spray pickling of strips. FIG. 2 is an explanatory diagram showing an embodiment of the device of the present invention. 1... Cooling room, 2... Spray pickling room, 3... Spray nozzle group, 4... Collection tank, 5, 11... ... Conduit, 7, 8...
Reservoir, 9. 10. 12. 13...Switching valve, 6...Support roller.

Claims (2)

[Scope of utility model registration request] (1) In a device configured to circulate and inject an acid aqueous solution onto a moving strip, a plurality of storage tanks are provided to store the acid aqueous solution after injection, and each storage tank is configured to be able to be used selectively. Continuous spray pickling equipment for strips featuring: (2) Utility model registration claim 1, characterized in that acid aqueous solutions of different concentrations or temperatures are stored in each storage tank.
Apparatus for continuous spray pickling of strips as described in Section.