JPS62136581A - Continuous pickling method - Google Patents

Abstract

PURPOSE:To shorten the time for pickling by heating a material to be pickled to a high temp. then pickling the material so that the scale on the surface of the material to be pickled is made easily peelable. CONSTITUTION:The material to be pickled is heated to the temp. above the b.p. of an acid soln. under the atm. pressure. The heated material to be pickled is pickled by immersing the material into the above-mentioned acid soln. or the like. The surface scale is finely cracked at the moment when the material to be pickled is immersed into the acid soln. The scale is peeled by the quick expansion of the gas generated when the acid soln. intruding into the cracks evaporates. The time for pickling is thus shortened.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for continuous pickling of metal materials, particularly steel plates.

[Conventional technology]

An example of a conventional continuous pickling device is shown in Fig. 246.

In Figure 6, 1 is a copper band, 2 is an acid tank, 3 is an acid tank,
4a, 4b, 4c, 4d, and 4e are guide rolls.

After being unwound from a payoff reel (not shown), the steel strip 1 at normal temperature is run while being immersed in the acid solution 3 in the acid tank 2. During this time, the scale that had formed on the surface of the steel strip is blown away by the acid solution 3. The steel strip 1 that has been pickled, removed, and descaled comes out of the acid tank 2 and is supplied to a subsequent process (not shown).

[Problems to be solved by the invention] Continuous pickling equipment requires that the surface of the copper strip be in contact with the acid solution for a certain period of time, so if the steel strip is traveling at a high speed, A long acid tank is required.

By the way, there is a strong demand for shorter acid tanks these days due to equipment costs and installation space.As a way to shorten acid tanks, a mechanical scale breaker is used to cut the copper strips before immersing them in the acid tank. - The scale is made to have a fine rank by passing through it, making it easier to remove the scale, and the reaction time is shortened by showering the steel strip with a jet of acid solution in the identification tank. has achieved results. Still, the length of the acid tank is 50~
A length of 100 m is required, and such a long acid tank requires low equipment costs and a large amount of equipment space. Therefore, there is a strong need to shorten this acid tank on the day of death.

[Objective] An object of the present invention is to provide a continuous pickling method that can shorten the time required for pickling and, as a result, shorten the length of the acid tank used.

[Means for solving problems]

In the present invention, as a means to achieve the above object, the material to be pickled is heated to a high temperature.

That is, the present invention provides a method for continuously pickling a material to be pickled, which is characterized in that the material to be pickled is heated to a temperature equal to or higher than the boiling point of the acid solution under atmospheric pressure, and then pickled. This is a washing method.

To explain the present invention specifically, a ninth heating device is provided upstream of the tank of the present invention for heating the copper strip, which is the material to be pickled, and the heating device uses the ninth heating device to heat the copper strip, which is the material to be pickled, under atmospheric pressure. The steel strip is heated to a temperature higher than the boiling point of the steel strip, and then the steel strip is introduced into an acid tank for pickling treatment.

According to the present invention, at the moment the copper strip is immersed in the acid solution, the acid solution at a temperature below the boiling point contacts the copper strip at a temperature above the boiling point, so that the scale becomes fine and ranks on the surface of the steel strip. Due to the rapid expansion of gas due to boiling and evaporation of the injected acid solution,
Scale 4 peeling occurs, new cranks appear,
This shortens the pickling time.

〔Example〕

Examples of the present invention are shown in Fig. m1, Fig. 2, and Fig. 3.

and shown in FIG. Figure 1 shows an example in which a heating device is installed upstream of an acid tank, where 1 is a copper strip, 2 is an acid tank, 3 is an acid solution,
4a, 4b, 4c, 4eL, 4e are guide roll%
6a, 6bn This is a heating device such as an electric type or a hot air type. After the steel strip 1 is heated by heating devices 6a and 6b to a temperature higher than the boiling point of the acid solution at atmospheric pressure, it is immersed in the acid solution 3 in the acid tank 2 to be pickled. Figure 2 shows another embodiment, which is equipped with a heated water tank as a heating device. The heating water tank 7 in FIG. 2 is a closed type, and a pair of seal rolls 9a, 9b, 9c, and 9d are installed at the entrance and exit of the steel strip 1 in the heating water tank 7, respectively. The opening gap between the inside of the heated water tank 7 and the outside world is kept small, and the inside of the heated water tank 7 is maintained at a high temperature and pressure while the W4 engine 1 can run continuously. The heated water tank 7 is filled with high-temperature pressurized water 8. 10a, 1
0b and 10c are guide rolls.

FIG. 3 shows another embodiment. As in the case of Figure 1,
Either heating devices 6a and 6b are provided in front of the acid tank, or the acid tank 2 is equipped with a seal roll 5a.

5b, sc, and sa are pressure sealed, and the n% reforming liquid 3 is kept at high pressure in the acid tank 2 at a temperature higher than the boiling point at atmospheric pressure. In this example, the temperature of the steel strip 1 at the outlet of the heating devices 6a, 6b is
The heating type is heated up to a high temperature. 4a, 4b, 4
c.

4 (L, 4e, 4f, 4g with Kaitrol.

FIG. 4 shows yet another embodiment. Either an acid tank 2 similar to that shown in FIG. 3 is provided, or a heated water tank 7 is provided as a heating device upstream of the acid tank. 8 is high temperature pressurized water, 9
a, 9b, 9c.

9d is a roll; 10a, 10'b, and 10c are guide rolls.

In the pickling means according to each of the above embodiments, the steel strip is immersed in the acid solution after being heated to a high temperature higher than the boiling point of the acid solution at atmospheric pressure. On the surface, the scale is fine, and due to the rapid expansion of the gas due to boiling and evaporation of the acid solution that has entered the rack, the scale i < ti,
Severe cracks will occur and the pickling time will be shortened.

According to experiments conducted by the present inventors, as shown in Figure 5, the higher the temperature of the copper plate, the shorter the pickling time. or less than 50%. If the temperature of the acid solution in the acid tank is above the boiling point at atmospheric pressure, the same effect as υ can be obtained by heating the steel plate to a temperature higher than that using a sword heating device.

[Effect] As described in detail above, the present invention involves heating the material to be pickled to a high temperature and then pickling it, so the material to be pickled is immediately immersed in the acid solution. The rapid expansion of gas due to boiling and evaporation of FC pickling when the scale is fine on the surface and evaporation causes peeling of the scale and the occurrence of cracks similar to firewood, which shortens the pickling time. This also has the effect that the acid tank can be shortened.

[Brief explanation of drawings]

Figures 1 to 4 are block diagrams of an apparatus suitable for the pickling method according to the embodiment of the present invention, in which the medial malleolus 1 is equipped with a heating device upstream of the acid tank; Figure 5 shows a model equipped with a heated water tank as a heating device, Figure 5 is the same as Figure 1, but the inside of the acid tank is kept in sieve soil, and the fc type is used, while Figure 4 uses a heated water tank. , and maintains the inside of the acid tank at high pressure. FIG. 5 is a graph showing the relationship between steel plate temperature and pickling time ratio, and FIG. 6 is a block diagram of a conventional pickling apparatus.

Claims (1)

[Claims] A method for continuously pickling a material to be pickled, characterized in that the material to be pickled is heated to a temperature equal to or higher than the boiling point of an acid solution under atmospheric pressure, and then pickled.