JP3252047B2 - Degreasing and cleaning method for metal strip - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to oils such as various kinds of rolling oils including lubricating oils, grinding oils and mineral oils, and kraft paper chips, fibers, dusts, metal powders and the like used for slip sheets. Solid deposits from the surface of the metal strip with high precision,
The present invention relates to a method and an apparatus for degreasing and cleaning a metal strip for cleaning a surface.

[0002]

2. Description of the Related Art Generally, in the production of metal strips such as stainless steel strips and alloy strips, oils such as lubricating oils, grinding oils and mineral oils and other rolling oils are used in a production line. For cold rolling of a steel strip or the like, a mineral oil or other rolling oil is used for lubrication and cooling. Therefore, metal powder and the like are mainly attached to the surface of the metal strip, mainly the rolling oil. Such a steel strip or alloy strip is subjected to non-oxidizing annealing in a bright annealing furnace, or after being annealed in an annealing and pickling facility, and then subjected to acid removal to remove oxide scale on the surface of the steel strip and the like generated by the annealing. Washed.

In the case of performing such an annealing and pickling treatment, as described above, rolling oil or the like adheres to the surface of the metal strip, and the adhesion state is uneven and uneven. If such a metal band is continuously passed through the annealing and pickling equipment as it is, an oil film pattern is formed on the surface of the metal band after the annealing and pickling by rolling oil, etc. Are generated unevenly, and the surface quality of the metal strip after pickling is significantly reduced.

If oil or solid deposits adhere to the surface of the steel strip or alloy strip and remain (remain), even if printing or painting is performed on the surface of the steel strip or alloy strip, the ink or Due to poor adhesion of the paint, the steel strip or steel sheet may be required to be almost completely degreased as a product. Therefore, such a metal strip production line is provided with a degreasing / washing step upstream or downstream of a predetermined facility among the facilities of a plurality of processes. In addition, a single degreasing and washing step is provided between the last production lines to provide clean steel strips and steel sheet products.

A prior art for realizing such a degreasing and washing step is disclosed in, for example, Japanese Patent Application Laid-Open No. 3-249135. In this prior art, since foreign matters such as rolling oil and metal powder adhere to the surface of the stainless steel strip after cold rolling and remain (remain), the material of the stainless steel strip after annealing and pickling is not suitable. Prior to annealing the stainless steel strip, the temperature of the stainless steel strip should be 70 ° C. or higher and not higher than 300 ° C. in order to prevent the uniformity from occurring and the deterioration of the steel strip surface quality. It is disclosed that a reducing flame is brought into direct contact with the surface of a strip to vaporize or burn off deposits mainly containing rolling oil to remove the deposits.

In this prior art, as a reducing flame, a gaseous fuel such as propane gas and an oxygen-containing gas such as air are mixed so that the air ratio becomes 0.2 to 0.6. In addition, the stainless steel strip should not be heated to a high temperature of 300 ° C. or higher, and the atmosphere gas around the reducing flame should be set to an oxygen concentration of 0.5% or less to prevent the formation of oxide scale on the surface of the stainless steel strip. Preventing.

The reason why the reducing flame is brought into direct contact with the surface of the stainless steel strip is that, as described in the prior art of this prior art, an organic solvent is used as a pretreatment for annealing and pickling. Alternatively, a method in which the stainless steel strip is immersed in an alkali solution and then washed with a cleaning brush while spraying water is expensive, so that such a cost problem was solved. Above, the rolling oil and dirt adhering to the surface of the stainless steel strip are removed without causing scratches and the like, and therefore, the extent to which the rolling oil and dirt are removed is not considered a problem. Further, even if the oxide scale is slightly generated on the surface of the stainless steel strip by this, it is heated in the next annealing and the oxide scale is generated. However, for example, to provide customers with stainless steel strips and steel sheets as products used for a wide variety of applications, and especially to print on the product surfaces of stainless steel strips and steel sheets, make the surface very clean. It is necessary to remove oil and solid deposits (foreign matter) with high accuracy, and it is necessary to achieve high wettability. That is, the reducing flame is brought into direct contact with the surface of the stainless steel strip to evaporate the oil,
In the method of vaporizing or burning, solid deposits (foreign matter) such as metal powder cannot be reliably and precisely removed and cleaned, and high wettability of, for example, 40 dyne / cm cannot be achieved. Have difficulty.

[0008]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to improve the uniformity of the material and the surface quality of metal strips produced in and between metal strip production lines and to improve the surface quality as much as possible. In order to manufacture and provide clean metal strip products or metal sheet products to customers, cleaning liquids that are directly harmful to human health and life, and environmental pollution such as destruction of the ozone layer, etc. Without using a highly harmful cleaning liquid, and with high precision, remove and clean oil and solid deposits remaining on the metal strip surface (remaining) so that the surface quality of the metal strip does not deteriorate or deteriorate. It is an object of the present invention to provide a method and an apparatus for degreasing and cleaning a metal strip which can achieve high wettability.

[0009]

According to the present invention, a metal strip which is continuously passed through is washed with a cleaning liquid mainly containing an organic solvent or an alkaline solution, and then the surface of the metal strip is heated with a flame or This is a method for degreasing and cleaning a metal strip, wherein a flame is brought into direct contact with the surface of the metal strip to gasify oil.

Further, according to the present invention, after the surface of the metal strip to be continuously passed through is heated with a flame or the flame is brought into direct contact with the surface of the metal strip to gasify the oil component, the metal strip is treated with an alkali. Alternatively, the present invention is a method for degrease and cleaning a metal band, wherein the metal band is cleaned with a cleaning solution comprising an aqueous solution mainly composed of an alkali.

Further, the present invention provides a flame in which the flame is in the region from the reducing flame to the neutral flame, and is in a range from a range where complete combustion does not occur and a range where soot is not generated as much as possible to a range close to complete combustion. It is characterized by being selected for the fuel ratio.

Further, according to the present invention, the air-fuel ratio is 0.4 to 1.
2 is selected.

Further, according to the present invention, the air-fuel ratio is 0.95 to 0.95.
1.15.

Further, the present invention is characterized in that cooling is performed by heating with a flame or by bringing a cooling roll into contact with the surface of the metal strip opposite to the surface of the metal strip with which the flame is in direct contact.

Further, according to the present invention, the cleaning liquid may be hot water and / or hot water.
Alternatively, steam is used.

Further, the present invention is characterized in that an alkali or an aqueous solution mainly containing an alkaline system is used as the cleaning liquid.

Further, the present invention relates to a burner provided so as to heat the surface of a metal strip continuously passed by a flame over the entire length in the width direction or to bring the flame into direct contact with the surface of the metal strip over the entire width direction. Mixed gas supply means for mixing the combustion gas containing oxygen and the fuel at an air-fuel ratio in a range where complete combustion does not occur and a range in which soot is not generated as much as possible to a range near a complete combustion range and supplies the mixture to the burner. A cooling roll that is heated by a flame from the burner or a surface opposite to the surface of the metal strip to which the flame is directly contacted is wound around and contacts the burner and the cooling roll. Cleaning means for immersing the surface of the metal strip continuously passed through the cleaning strip in a cleaning liquid and condensing the vapor of the cleaning liquid to condense the cleaning. A.

[0018]

According to the present invention, the metal strip which is continuously passed through is exposed to solid deposits such as oil and metal powder (foreign matter) adhering to the surface of the metal strip by a cleaning liquid mainly containing an organic solvent or an alkaline solution. ), The metal band surface is indirectly heated with a flame, for example, in a state of being roasted, or the flame is brought into direct contact with the surface to remove residual oil and the like that could not be completely removed by the cleaning liquid or the like. Gasification is carried out by evaporation in a low temperature range below the boiling point, rapid vaporization near the boiling point or mild combustion.

As described above, by first cleaning the surface of the metal band with a cleaning liquid or the like, most of the oil and the like on the surface of the metal band are removed, and solid matter such as metal powder is almost completely removed. it can. However, the remaining oil, which slightly adheres to the surface of the metal strip and remains (residual), is more actively gasified and removed by the flame. Gasification of oil etc. in a relatively low temperature non-oxidizing flame and non-oxidizing environment atmosphere that can suppress the oxidation of the surface of the metal band, oxidizes the surface of the metal band and generates oxide scale Can be prevented.

Further, the cleaning liquid has a very high degreasing ability, such as chlorofluorocarbon (general term for fluorinated hydrocarbons) and halon (generic term for fluorinated hydrocarbons including bromine), but also has environmental pollution such as destruction of the ozone layer. Highly toxic organic solvents that cause harm, trichloroethane that is slightly harmful to human health and life, and especially harmful to the destruction of the ozone layer, and destruction of the ozone layer that are harmful to humans The use of an organic solvent which is a chlorinated hydrocarbon having a high degreasing ability, such as trichlorethylene, which is not so harmful to such substances, is minimized.

Even if it is used, never use only a highly harmful organic solvent that leads to environmental pollution, for example, by taking measures to make the above-mentioned trichlorethylene harmless to humans and taking measures for equipment. Alternatively, even if the degreasing ability is slightly reduced, for example, an alcohol-based, paraffin-based, or kerosene (based) cleaning solution can be used while being selected according to the purpose of use or the required surface condition after degreasing and cleaning. .

Therefore, as the cleaning liquid, in addition to the organic solvent as described above, a cleaning liquid mainly containing a conventionally used general alkaline solution or the like can be used.

In other words, at least the use of a harmful organic solvent which causes environmental pollution and the like as a cleaning solution can be performed without harm or detoxification to humans. Even if a small amount of oil etc. adheres to the surface of the metal strip and remains after cleaning using a low-performance cleaning solution, even if a small amount of the cleaning solution remains as well as this oil etc., such residual oil etc. Can be gasified by a flame after washing, so that the surface of the metal strip can be degreased, washed and cleaned with a high degree of degreasing and washing performance.

According to the present invention, first, the surface of the metal strip to be continuously passed is heated indirectly with a flame or the flame is brought into direct contact with the surface to evaporate oil or the like adhering to the surface.
It is gasified by vaporization or mild combustion. Next, the metal strip is washed with a washing liquid such as water, an alkaline solution, an organic solvent, etc., to remove a small amount of residual oil and the like and solid deposits (foreign matter) such as metal powder that could not be completely removed by the gasification by the flame. can do. In this way, by first gasifying and removing oil and the like by the flame, the subsequent degreasing and cleaning treatment with the cleaning liquid is facilitated,
It is done efficiently and economically. That is, by reducing the amount of recovered oil per unit cleaning area of the surface of the metal strip that is collected and removed in the cleaning liquid, the amount of suspended solids in the waste liquid is reduced, the amount of waste liquid treatment is reduced, and the amount of the cleaning liquid is reduced. By reducing the number of replacements or reducing the amount of replenishment of a new cleaning liquid, the consumption of the cleaning liquid can be reduced.

The cleaning liquid is made harmless or detoxified with water, an alkaline solution or an organic solvent without using a cleaning liquid that is harmful to humans or a highly harmful cleaning liquid that causes environmental pollution. The cleaning liquid in the state may be appropriately selected and used, and it is possible to use a cleaning liquid having a slightly lower degreasing ability, and use a cleaning liquid having a high degreasing ability that is harmful to humans and the environment. Can be avoided.

In addition, since the oil and the like adhering to the surface of the metal band are gasified and then washed with the cleaning liquid, not only the oil and the like adhering to the surface of the metal band but also solid deposits can be removed with high precision degreasing and cleaning performance. To achieve a high degree of cleaning and wettability of the metal strip surface.

As described in detail above, in the present invention, in order to efficiently and efficiently remove oil and the like and solid deposits adhering to the surface of the metal strip, gasification and scattering of the oil and the like and solid deposits are performed. And the cleaning means are used together, but either means may be performed first. Which method is performed first depends on various conditions and conditions such as the purpose of degreasing and cleaning of the metal band, the required degreasing and cleaning accuracy and the deterioration of the surface of the metal band, the allowable degree thereof, the degreasing cleaning machine and the place, and the like. May be appropriately selected. In any case, by using both means together, the two means complement each other and act synergistically to achieve the above-described object (object) of the present invention.

Further in accordance with the present invention, the flame that heats or directly contacts the surface of the metal strip includes:
A flame in the range from a reducing flame to a neutral flame that does not lead to an oxidizing flame, and is selected as an air-fuel ratio in a range where complete combustion does not occur and a range in which soot is not generated as much as possible to a range near a complete combustion region. . As a result, soot is prevented from adhering to the surface of the metal strip as much as possible, and without generating oxidation scale on the surface of the metal strip in a non-oxidizing flame and a non-oxidizing atmosphere.
Oil and the like can be removed by gasification. The air-fuel ratio refers to a ratio of the amount of air required for actual combustion to the amount of theoretical air required for fuel (actual combustion air amount / theoretical air amount).

Further, according to the present invention, the air-fuel ratio is 0.1.
4 to 1.2 are selected. When the air-fuel ratio is less than 0.4, soot is generated in a considerably large amount. When the air-fuel ratio exceeds 1.2, an oxide scale is easily formed on the surface of the metal strip, and the thickness of the oxide scale increases and the allowable range is increased. This is because, even when is observed, the thickness increases to an unacceptable level. In order to simultaneously avoid the generation of soot, the generation of oxide scale, and the increase in thickness, it is necessary to select the air-fuel ratio in the range of 0.4 to 1.2.

According to the present invention, the air-fuel ratio is set to 0.1.
By selecting from the range of 95 to 1.15, the generation of soot is surely prevented, the securing of a non-oxidizing flame and the appearance of a non-oxidizing atmosphere are ensured, and the adhesion of soot and the formation of oxide scale and its formation The increase can be reliably prevented.

According to the present invention, furthermore, the heating surface by the flame or the direct contact of the flame with the heating surface or the flame by arranging and contacting the cooling roll on the surface opposite to the surface of the metal strip directly contacting the flame. Cool from behind the surface to be cleaned. As a result, the temperature rise on the surface of the metal strip is made as low as possible, and the oil and the like are gasified, but the initiation of the oxidation of the metal strip surface and its promotion can be prevented.

In most cases, it is necessary to remove oil and the like and solid deposits adhering to the surface opposite to the front surface of the metal strip, that is, the back surface. From the same place, after the gasification and scattering processing of the front side is completed according to the continuous passing of the metal band, the processing of the back side is performed, and then the cooling roll is arranged on the opposite side of the surface to be processed and brought into contact with each other while cooling and cooling It is desirable to continue.

According to the present invention, warm water and / or steam are used as the cleaning liquid. Such hot water and / or water vapor lowers the viscosity of the oil and the like adhering to the surface of the metal band, increases its fluidity, and can easily separate the oil and the like from the surface of the metal band. Since the hot water is harmless, it is easy to handle, and the oil and the like suspended in the warm water can be easily separated and the oil and the like in the waste liquid can be easily collected. Therefore, the equipment for regenerating the waste liquid is simple, has a wide dissolving power and a dispersing power for hydrophilic dirt, and can be easily and safely implemented. By not only immersing in such warm water, but also spraying warm water on the surface of the metal strip, spraying water vapor on the surface, treating the immersion and these sprays in an appropriate combination, etc. Can be further improved.

Further, according to the present invention, an aqueous solution mainly composed of an alkali or an alkali is used as the cleaning liquid. Such as sodium hydroxide (NaOH), ortho sodium silicate _{(2Na 2 O · SiO 2 ·} XH 2 O), metasilicate soda _{(Na 2 O · SiO 2 ·} XH 2 O) a surfactant and a chelating if necessary, such as An aqueous solution mainly containing an alkali or an alkaline system to which an additive such as an agent or an antifoaming agent is added has low harmfulness. For example, at a low concentration of about 3 to 5%, dirt containing heavy oil and the like and solid deposits is contained. Can be removed. Further, the waste liquid can easily float and separate most of the oil and the like by the neutralization treatment, so that the waste liquid treatment is easy. Instead of simply immersing in such an aqueous solution, an aqueous solution is sprayed on the surface of the metal band while using an electric field treatment means or a cleaning rotary brush together, and furthermore, with water, hot water, or steam as described above. By appropriately combining the immersion and these jetting means, it is possible to further improve the ability to remove dirt including oil and the like.

Further, according to the present invention, a burner is provided on one surface side of the continuously passed metal strip, and a cooling roll is provided on the opposite surface. A mixed gas is supplied to the burner by a mixed gas supply unit.
This mixed gas is mixed at an air-fuel ratio in a range in which the combustion gas containing oxygen and the fuel do not completely burn, and a range in which soot is not generated as much as possible to a range in the vicinity of the complete combustion. The burner to which such a mixed gas is supplied is provided so that the surface of the metal strip is heated with a flame over the entire length in the width direction or the flame is brought into direct contact with the surface of the metal strip over the entire length in the width direction. Such burner combustion evaporates oil and the like adhering to the surface of the metal strip,
It can be removed by vaporization or mild combustion.
The surface opposite to the front surface of the metal strip, that is, the back surface is wound around a cooling roll and contacted to be cooled. As a result, the temperature rise on the surface of the metal strip is suppressed, and gasified oil and the like adhered by the flame generated by the combustion of the burner, but the surface properties of the metal strip are prevented from being undesirably changed. it can.

In order to remove oil and the like adhering to the front and back surfaces of the metal band, in addition to such a pair of burners and a cooling roll, the metal band passing through another pair is also used. It is only necessary to reversely dispose them and remove them sequentially. Further, since the surface of the metal band is cleaned by the cleaning means and the dew condensation thereof by the cleaning means, oil and the like and solid deposits adhering to the surface of the metal band can be more reliably removed.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Although the method and apparatus for degreasing and cleaning a metal strip according to the present invention are not particularly illustrated and described, for example, in the production of a stainless steel strip and other high alloy strips, upstream of an annealing furnace in an annealing pickling facility. Solids such as oils such as rolling oils and polishing oils and metal powders on the side, upstream of the bright annealing furnace in the bright annealing equipment, and downstream in the finish polishing equipment for polishing with an endless belt using grinding oil. To maintain and improve the surface quality of the metal strip. Also, between the final lines of each production line, the apparatus is installed and implemented as a single apparatus in order to provide a metal strip product that has been cleaned with high precision and has also achieved high wettability.

The embodiment according to the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a simplified cross-sectional view of a degreasing and cleaning apparatus 1 in which a method for degreasing and cleaning a metal strip according to one embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a specific configuration of a cleaning means 8. 3, FIG. 3 is a plan view showing a specific configuration of the burner 4, FIG. 4 is a system diagram showing a specific configuration of the mixed gas supply means 5, and FIG.
FIG. 6 is a system diagram showing a specific configuration of the cooling water supply means 59.
7 is a graph showing the relationship between the air-fuel ratio and the oxide film thickness, and FIG.
FIG. 8 is a graph showing the abundance ratio of each of the elements Fe, C, Cr, and O with respect to the etching time by X-ray photoelectron spectroscopy.
FIG. 6 is a simplified cross-sectional view showing a degreasing cleaning device 1 according to another embodiment of the present invention.

The degreasing and cleaning apparatus 1 of this embodiment shown in FIG.
Basically, a case is shown in which the front and back surfaces of the metal band 3 continuously passed in the direction of arrow A are degreased and cleaned. (A direction perpendicular to the plane of the drawing), or a burner 4 provided so that both surfaces are brought into direct contact with the flame over the entire length in the width direction, for example, air as a combustion gas containing oxygen, and fuel. For example, a mixed gas supply unit 5 for mixing propane gas with an air-fuel ratio in a range where complete combustion does not occur and a range in which soot is not generated as much as possible to a range near a complete combustion range and supplies the mixture to the burner 4; A cooling roll 6 on which the surface opposite to the side heated or brought into direct contact with the flame is wound, and cooling water is supplied to each such cooling roll 6 Cooling water supply means 59 and a pair of burners 4 and cooling rolls 6 and a further pair of cooling water supply means 59 are disposed on the upstream side in the passing direction A of the metal strip 3 in close proximity to the pair of burners 4 and the cooling roll 6. Cleaning means 8 for cleaning the surface with a cleaning liquid 7;

When one surface of the metal strip 3 is degreased and cleaned, the metal strip 3 may be continuously passed except for one of the two pairs of burners 4 and the cooling roll 6.

On both sides of the cooling roll 6, a pair of bridle rolls 9, 10 are provided rotatably about a rotation axis parallel to the rotation axis of the cooling roll 6.
The outer peripheral surfaces of the bridle rolls 9 and 10 are covered with a heat-resistant rubber to prevent the surface of the metal band 3 from being damaged.
Further, the outer peripheral surface of the cooling roll 6 is coated with a synthetic resin having a high heat transfer coefficient, thereby preventing the surface of the metal strip 3 from being damaged.

The metal strip 3 continuously passed in this way is cooled by a cold rolling equipment (not shown) provided in another production line (process) while cold rolling oil is supplied and bitten by, for example, mineral oil. Rolled sheet thickness 0.1-3.0m
m, SUS30 with a board width of about 800 mm to 1570 mm
4, SUS430 stainless steel strip. As an example, the passing speed of such a metal strip 3 is 6 to 50 m / min in the finish polishing step, 5 to 60 m / min in the bright annealing step, and in the annealing pickling step. If there is 5
It is selected to be about 100 m / min.

FIG. 2 is a sectional view showing a specific structure of the cleaning means 8 shown in FIG. A liquid storage tank 13 is formed at the bottom of the cleaning tank 11, and the cleaning liquid 7 is stored in the liquid storage tank 13. The storage tank 13 is provided with a heater 14 for heating the cleaning liquid 7, and a part of the immersion roll 15 is buried in the cleaning liquid 7 heated to, for example, near the boiling point by the heater 14. The metal band 3 wound around the metal band 3 is immersed in a bath of the cleaning liquid 7 to remove solid matters such as oil and metal powder adhering to both surfaces of the metal band 3.

A cooling pipe 16 through which cooling water is circulated is provided at the upper part of the cleaning tank 11, and the vapor of the cleaning liquid 7 heated in the liquid storage tank 13 is cooled, and the vapor of the cleaning liquid 7 condenses. . Both surfaces of the metal strip 3 are also cleaned by the vapor of the cleaning liquid 7.

The cleaning liquid 7 is suspended in the storage tank 13 by mixing oil and the like and solid deposits attached to the metal band 3. The oil is guided to the separation tank 18 and separated from the oil and the like and the washing liquid by natural sedimentation. In the oil-liquid separation tank 18, since the oil content is smaller than the washing liquid 7, the oil collects in the upper layer, and solid deposits such as metal powder and a part of interleaf paper collect in the lower layer. , An intermediate layer occupied by the relatively clean cleaning liquid 7 is formed. Since the cleaning liquid 7 collected in such an intermediate layer contains fine oil and suspended matter, it is led to the distillation tank 20 via the pipe 19 and
While heating in step 1, oil dispersed in the liquid is separated. Here, too, the oil with a lower specific gravity collects in the upper layer, and the suspension with the higher specific gravity collects in the lower layer.

The cleaning liquid collected in the lower layer is purified as compared with the cleaning liquid in the intermediate layer in the above-mentioned oil-liquid separation tank 18, and the cleaning liquid is heated by the heater 21 to evaporate and distilled. The cleaning liquid cooled and liquefied by a cooling pipe 23 provided on the upper side of the tank 20 is supplied to a pipe 24.
Is fed into the liquid storage tank 13 and used again for degreasing and cleaning of the metal strip 3.

For example, a general-purpose multi-component concentration meter for measuring conductivity is provided in the distillation layer 20 to measure the oil concentration. When the oil concentration exceeds a predetermined oil concentration, the oil is led to the outside via a discharge line 25 as a waste liquid. , In a waste liquid treatment facility.

As the rinsing liquid 7, trichlorethylene (trade name: Tricrene) not specified as an ozone depleting substance is used as a lipophilic organic solvent. Such a chlorine-based synthetic organic solvent is generally nonflammable, has a very high degreasing ability, and is easy to regenerate because of its low boiling point. In particular, the trichloroethylene is 1,1,1-trichloroethane (C ₂ The risk of depletion of the ozone layer is lower than that of other chlorine-based synthetic organic solvents represented by H ₃ Cl ₃ ). The reason is that carbon in the molecular structure of trichloroethylene (C ₂ HCl ₃ ) has a double bond, so that the molecular bond is unstable and is decomposed before reaching the ozone layer.

Examples of such a cleaning liquid include trichlorethylene, which is a chlorine-based synthetic organic solvent having a high degreasing ability as described above, and generally has a low degreasing ability. And / or steam, such as sodium hydroxide, sodium orthosilicate,
In addition to simply immersing in an aqueous solution mainly composed of an alkali or an alkaline system such as sodium metasilicate, or a combination of these, an electric field treatment, a rotating brush for cleaning,
It can be used while appropriately combining and using spraying treatment and the like, and will be described briefly later.

FIG. 3 is a plan view showing a specific configuration of the burner 4. The burner 4 is a direct fire type burner called a ribbon burner. Flange joints 27 and 28 are fixed to both longitudinal ends of a cylindrical burner head 26, and a swivel joint 29 is attached to each flange joint 27 and 28. ,
30 are connected. At one end of each swivel joint 29, 30 connected to the flange joint 27, 28,
Piston rods 34, 35 of double acting pneumatic cylinders 31, 33
And a plurality of flame holes 36 formed in a straight line in the burner head 26 along the axial direction at a desired angle toward the surface of the metal strip 3 wound around the cooling roll 6. Thus, the configuration is such that the direction of flame injection can be adjusted.

The other ends of the swivel joints 29 and 30 are also displaceable in the directions of arrows B1 and B2 at right angles to the axis of the burner head 26. Such an arrow B
By displacing in the directions 1 and B2, the distance L1 to the surface of the metal strip 3 can be adjusted and the surface can be heated or brought into direct contact. The burner head 2
The length L2 in the axial direction of 6 is appropriately selected to be longer than the length including the width of the metal band 3, and is, for example, about 1.7 m. The other end of each of the swivel joints 29 and 30 has a region where complete combustion is not performed and a region where soot is not generated as much as possible in order to make the flame exiting from the flame hole 36 a reducing flame or a neutral flame. Supply ports 37 and 38 are provided to supply a mixed gas of a fuel selected to an air-fuel ratio up to a nearby range and a combustion gas containing oxygen. Here, the air-fuel ratio is the ratio of the amount of air required for actual combustion to the amount of theoretical air required for fuel (actual air amount / theoretical air amount).
Further, the fuel may be propane gas (abbreviated as LPG) or liquefied natural gas (abbreviated as LNG). Air is used as the combustion gas.

FIG. 4 is a system diagram showing a specific configuration of the mixed gas supply means 5. The gas fuel filled in the pressure vessel 39 is decompressed to a predetermined pressure by a decompressor 41 interposed in a pipe 40, and then guided to an air-fuel ratio adjusting means 45 through a main valve 43 and a zero governor 44, where the air-fuel ratio is adjusted. Adjusting means 45
Is supplied to the mixer 46.

On the other hand, the combustion air sucked by the blower 47 is supplied to the mixer 46 via pipes 48 and 49. A part of the combustion air supplied to the pipe 48 is guided to a combustion chamber 51 via a pipe 50. In the mixer 46, the gas fuel whose flow rate has been adjusted by the air-fuel ratio adjusting means 45 and the combustion air supplied through the pipes 48 and 49 are mixed and led out to the pipe 53. The mixed gas in the pipe 53 is guided to the combustion chamber 51 by the pipe 54 and is burned by the combustion air supplied from the pipe 50, and the O ₂ concentration at this time is detected by the flame arrester 55. Is done. The supply amount of the gas fuel in the air-fuel ratio adjusting means 45 is adjusted based on the O ₂ concentration.

The mixed gas derived from the pipe 53 is
Flexible hoses 57, 58 made of metal via a conduit 56
Are supplied to the gas supply ports 37, 38 of the swivel joints 29, 30 respectively. Gas fuel can be supplied to the burner 4 at an arbitrary air-fuel ratio by the mixed gas supply means 5 having such a configuration.

FIG. 5 is a system diagram showing a configuration of the cooling water supply means 59 for supplying the cooling water supplied to the cooling roll 6. The cooling roll 6 is hollow and allows cooling water to flow from one end in the axial direction to the other end. Both ends in the axial direction of the cooling roll 6 are pivotally supported by a pair of rotary joints 60, 61, and cooling water can be supplied or discharged from outside via the rotary joints 60, 61. .

For example, a pipe 64 connected to a connection port of one rotary joint 61 is connected to an upper part of a tank 63 capable of storing about 1.5 m ^{3 of} circulating water, and a lower part of the tank 63 is connected to a lower part of the tank 63. Rotary joint 60
Is connected to the connecting line 65. The tank 63, the pipes 64 and 65, and the cooling roll 6 constitute a circulation channel. For example, cooling water at a temperature of about 32 ° C. is supplied to the tank 63 at a flow rate of 1.5 m ³ / hour at a supply pressure of 0.5 kg / cm ² from a cooling water supply pipe 66.

The cooling water supply pipe 66 has a temperature control valve 6
7, a temperature detector 90 provided in the tank 63
The supply amount of the cooling water supplied to the tank 63 via the pipe 66 can be adjusted based on the water temperature in the tank 63 detected by the above. The water temperature in such a tank 63 is normally maintained at 40 ° C.
Therefore, steam having a flow rate of 20 kg / h is supplied into the tank 63 through the conduit 68 at a supply pressure of 5 kg / cm ² . Thus, the temperature of the water in the tank 63 is raised. It should be noted that raising the water temperature in the tank 63 by the water vapor in this manner is used only at the time of startup in which the cooling roll 6 is not heated by contact with the metal strip 3,
After startup, the temperature of the cooling water circulating in the cooling roll 6 rises, so that there is no need to heat it.

The pipe 65 is provided with a pump 69.
The cooling water in the tank 63 can be circulated and supplied to the cooling roll 6. Excess cooling water in the tank 63
It is discharged into a pit 71 provided in the factory via a pipe 70. Suspended matter such as sludge accumulated at the bottom of the tank 63 can be discharged to the pit 71 via a pipe 73.

As described above, the metal strip 3 continuously passing through the degreasing and cleaning equipment of this embodiment is immersed in the cleaning liquid 7 composed of, for example, a trichloroethylene solvent, and the oil and the like adhering to the surface thereof and metal powder or polishing Removal of dirt from solid deposits such as powder, and then heating with a reducing flame or a neutral flame from the burner 4 using a gas fuel whose air-fuel ratio is controlled in the range of 0.4 to 1.2. Alternatively, a flame is brought into direct contact to gasify, that is, evaporate, evaporate, or lightly burn the oil remaining on the surface of the metal band 3, thereby completing the degreasing of the surface of the metal band 3. On the opposite side of the burner 4, the above-described cooling roll 6 is provided for cooling, and the temperature rise of the metal strip 3 is suppressed.

[0061]

[Table 1]

Table 1 shows the residual oil content on the surface of the metal band 3 and the number of stains on solid deposits when the above-described degreasing treatment was performed. The residual oil content was determined by washing the cut steel sheet with carbon tetrachloride CCl ₄ and quantifying the carbon tetrachloride solution by infrared absorption spectroscopy. The residual amount after immersion in the trichloroethylene cleaning solution is 21 mg / m ² , which is not enough, compared to 973 mg / m ² before the treatment. That is, even if printing is performed on the surface of the metal band 3 where such an oil component or the like remains, no ink is deposited. Therefore, by performing the subsequent flame degreasing with the burner 4, the residual oil content becomes less than 2 mg / m ² , and most of the stains on the solid deposits are washed off by the washing action of the washing liquid. In this manner, oil and the like and solid deposits adhering to the surface of the metal strip 3 can be ultra-precisely cleaned to realize high-precision cleanliness (cleanability) and wettability. Next, the air-fuel ratio of the mixed gas burned by the burner 4 will be described.

FIG. 6 shows the air-fuel ratio and, for example, SUS304,
SUS430 stainless steel strip The relationship between the ratio of the thickness of the oxide film on the surface of the metal strip and the passing speed of the steel strip is 5 m / min.
It is a graph which shows the situation investigated about 50m / min. The mixed gas supplied to the burner 4 is controlled by the mixing / supplying means 5 so that the air-fuel ratio is in the range of 0.4 to 1.2. That is, when a mixture of a hydrocarbon gas fuel such as propane gas and an oxygen-containing gas, such as air, is burned, a flame near a region where complete combustion occurs to complete combustion, that is, a reduction that does not lead to an oxidizing flame. Neutral flame is generated from the flame, but such reducing flame or neutral flame is used because oil etc. on the metal band surface evaporates,
This is to prevent the surface of the metal strip 3 from being oxidized when vaporized or burned lightly, thereby preventing generation of oxide scale as much as possible. By heating the surface of the metal strip in a non-oxidizing reducing flame or neutral flame and a non-oxidizing atmosphere, only the oil etc. is gasified without oxidizing the surface, and only the oil etc. is almost completely removed. can do.

When the air-fuel ratio exceeds 1.2, the thickness ratio of the oxide film increases, as is apparent from FIG. Soot adheres to the surface. Therefore, the air-fuel ratio is 0.4 ~
1.2 is selected. More preferably, by burning in an air-fuel ratio in the range of 0.95 to 1.15, that is, in a range close to complete combustion, without causing oxidation and adhering soot, and improving the fuel efficiency, Etc. can be gasified.

The curve shown in the figure is obtained by X-ray photoelectron spectroscopy.
n spectroscoty for chemicalanalysis), abbreviated as ESC
In the evaluation method A), as shown in FIG.
P1 is defined as the boundary between the oxide film and the base of the metal strip, and the depth up to this point P1 is defined as the thickness of the oxide film. In addition, the intersection P2 of Cr and O is taken,
A point where 2 / 3Fe = 0 and P3 may be used as a boundary. However, in this evaluation method, since the relationship between the etching time [min] on the horizontal axis and the abundance ratio [%] of each element on the vertical axis was obtained using SiO ₂ as a standard, the metal band was a stainless steel band. In such cases, the etching rates are different. Therefore, the absolute amount of the thickness of the oxide film cannot be obtained.

FIG. 8 is a sectional view showing a schematic configuration of another embodiment of the present invention. Parts corresponding to those in the above-described embodiment are denoted by the same reference numerals. In this embodiment, it should be noted that the burner 4 and the cooling roll 6 are provided on the upstream side of the cleaning means 8, and the cleaning liquid 7 uses hot water.
The metal strip 3 continuously passed through such a degreasing and washing apparatus is
First, the air-fuel ratio should be 0.4 to 1.2, more preferably 0.9.
By heating the surface of the metal band with the reducing flame or neutral flame of the burner 4 using a gas fuel controlled to 5 to 1.15, oils and the like are gasified, and then immersed in a warm water bath to remove the metal powder. Remove solid deposits such as powder and abrasive powder, and complete the degreasing and cleaning of the metal strip. Table 2 shows the residual oil content and the number of solid deposits on the surface of the metal band when the degreasing and cleaning treatments of this example were performed.

[0067]

[Table 2]

In the same manner as in the above embodiment, the oil content and the like were determined by washing the cut steel sheet with carbon tetrachloride and quantifying the carbon tetrachloride solution by infrared absorption spectroscopy. Before the treatment, the amount of the adhered oil was 1005 mg / m ^2.
The residual amount after flame degreasing was 2 mg / m ²
The removal of oil and the like is almost completely completed, but the number of stains on the solid deposits has not decreased so much from 100 to 89. Then, by immersing in a warm water bath, the number of stains on the solid deposit can be significantly reduced to five.

When degreased cleaning is performed by the cleaning apparatus of the embodiment shown in FIGS. 1 to 8, it is possible to achieve a high degree of wettability in addition to a high degree of cleaning. It was confirmed by the present inventor that this was possible.

The present inventors conducted the following experiment in order to confirm that the wettability was improved. That is, in the degreasing and cleaning apparatus 1 of the embodiment shown in FIG. 1, the distance between the flame holes 36 of the metal strip 3 and the burner 4 is set to 38.1 mm.
When it was brought into contact with a reducing flame burning at an air-fuel ratio of 1.0 at a passing speed of 0 m / min, a wettability of 54 dyne / cm or more was confirmed.

In still another embodiment of the present invention, an aqueous solution mainly composed of an alkaline organic solvent may be used as the cleaning liquid. As such an aqueous solution, sodium silicate is preferable. In this case, the temperature of the cleaning liquid is set to about 70 ° C., the concentration is set to about 3%, electrolytic cleaning is performed at a current density of about 2.0 sec with a quantity of electrolytic electricity of 10 A / dm ² , and a cleaning rotary brush made of synthetic resin is used. The surface of the metal strip may be cleaned.

In still another embodiment of the present invention, a non-alkali or non-alkali degreasing agent may be used as a cleaning liquid. As such a non-alkali degreaser, for example, an aqueous alcohol degreaser and a petroleum degreaser such as paraffin or kerosene are preferable. By using such a detergent, sufficient safety can be ensured in terms of water pollution and air pollution.

The degreasing cleaning method and the degreasing cleaning device of the present invention can be carried out by incorporating them into an annealing pickling line, a bright annealing line, an alkaline degreasing cleaning line and a finish polishing line, as well as a single degreasing cleaning line. . In addition, the suspended waste liquid after the degreasing and washing may be removed by a commercially available centrifugal separator, and the cleaned washing liquid may be sent to the washing tank again for reuse.

[0074]

According to the present invention, after cleaning with a cleaning solution,
Oil and the like on the surface of the metal strip are removed by reducing flame or neutral flame, so oil and other solids and solids that adhere to the surface of the metal strip and remain without using a highly harmful cleaning solution that causes environmental pollution. Attached matter (foreign matter) can be removed and cleaned with high precision, and a high degree of wettability can be achieved on the surface thereof.

According to the present invention, the surface of the metal strip is cleaned with a cleaning liquid composed of an aqueous solution mainly composed of an alkali or an alkali, after removing the oil and the like by a reducing flame or a neutral flame. It is possible to sufficiently degreasing and clean even with a slightly degreasing cleaning liquid without using a highly harmful cleaning liquid that causes such problems as oils, etc. and solid deposits (foreign matter) adhering to the surface of the metal band.
Can be removed with high precision to achieve cleaning and high wettability.

Further, according to the present invention, the air-fuel ratio of the reducing flame or the neutral flame is selected from a range in which complete combustion is not performed and a range in which soot is not generated as much as possible to a range in the vicinity of complete combustion. It is possible to prevent the material from being changed and the surface thereof from being oxidized.

Further, according to the present invention, the air-fuel ratio is set to 0.1.
Since the selection is made in the range of 4 to 1.2, the oxidation of the surface of the metal strip can be more reliably prevented.

Further, according to the present invention, the air-fuel ratio is set to 0.1.
Since the selection is made in the range of 95 to 1.15, oxidation of the surface of the metal strip can be reliably prevented and fuel can be saved.

Further, according to the present invention, the metal strip is heated by a reducing flame or a neutral flame, or the surface opposite to the surface of the metal strip contacted with the reducing flame or the neutral flame is cooled. In this way, it is possible to prevent deterioration of the material and surface properties due to the heat, and to reliably prevent oxidation of the surface.

Further, according to the present invention, since warm water is used as the cleaning liquid, it is harmless and inexpensive, and the separation of oil and water of waste liquid including oil after cleaning is easy.

Further, according to the present invention, an alkali or an aqueous solution mainly composed of an alkaline system is used as the cleaning liquid, so that oil and the like adhering to the surface of the metal strip can be removed with a high degreasing ability, which causes environmental pollution. By avoiding the use of a highly harmful cleaning liquid, it is possible to degrease and clean with high precision and to achieve high wettability.

Further, according to the present invention, the surface of the metal band to which solid matter such as oil and metal powder adheres is heated by a reducing flame from a burner or a neutral flame, or the surface of the metal band is heated by a reducing flame from a burner. The neutral flame is brought into direct contact, and the opposite surface is brought into contact with a cooling roll for cooling, and the metal band is washed with a washing liquid and its dew. To achieve a high degree of wettability.

[Brief description of the drawings]

FIG. 1 is a simplified cross-sectional view of a degreasing and cleaning apparatus 1 in which a method for degreasing and cleaning a metal strip according to an embodiment of the present invention is performed.

FIG. 2 is a cross-sectional view illustrating a specific configuration of a cleaning unit 8;

FIG. 3 is a plan view showing a specific configuration of a burner 4;

FIG. 4 is a system diagram showing a specific configuration of the mixed gas supply means 5.

FIG. 5 is a system diagram showing a specific configuration of a cooling water supply unit 59;

FIG. 6 is a graph showing a relationship between an air-fuel ratio and a ratio of an oxide film thickness.

FIG. 7 shows each element Fe, C, Cr,
6 is a graph showing the abundance ratio of O to the etching time.

FIG. 8 is a simplified sectional view showing a degreasing / cleaning apparatus 1 according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Degreasing | cleaning apparatus 3 Metal strip 4 Burner 5 Mixed gas supply means 6 Cooling roll 7 Cleaning liquid 8 Cleaning means 11 Cleaning tank 26 Burner head 45 Air-fuel ratio adjustment means 59 Cooling water supply means

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C23G 3/02 C23G 1/19 C23G 1/24 C23G 5/00 C23G 5/02

Claims (9)

(57) [Claims] After washing a metal strip continuously passed with a cleaning liquid mainly comprising an organic solvent or an alkaline solution, the surface of the metal strip is heated by a flame or a flame is applied to the surface of the metal strip. A method for degreasing and cleaning a metal band, wherein the oil is gasified by direct contact. 2. After heating the surface of the metal strip to be continuously passed with a flame or directly contacting a flame with the surface of the metal strip to gasify oil, the metal strip is treated with an alkali or alkaline system. A cleaning method for a metal strip, comprising cleaning with a cleaning solution comprising an aqueous solution mainly comprising: 3. The flame is a flame in a region from a reducing flame to a region near a neutral flame, and is selected to have an air-fuel ratio from a range where complete combustion does not occur and a range where soot is not generated as much as possible to a range near complete combustion. The method for degreasing and cleaning a metal strip according to claim 1 or 2, wherein the cleaning is performed. 4. The method according to claim 3, wherein the air-fuel ratio is selected from 0.4 to 1.2. 5. The degreasing method according to claim 3, wherein the air-fuel ratio is selected from 0.95 to 1.15. 6. The cooling method according to claim 1, wherein the cooling is carried out by heating with a flame or by bringing a cooling roll into contact with the surface of the metal strip opposite to the surface of the metal strip with which the flame comes into direct contact. Cleaning method for metal strips. 7. The method for degreasing and cleaning a metal strip according to claim 1, wherein the cleaning liquid uses hot water and / or steam. 8. The cleaning liquid according to claim 1, wherein an alkali or an aqueous solution mainly containing an alkaline system is used.
The method for degreasing and cleaning a metal band according to any one of 3 to 6. 9. A burner provided to heat the surface of the metal strip to be continuously passed with a flame over the entire length in the width direction or to bring the flame into direct contact with the surface of the metal strip over the entire length in the width direction; A mixed gas supply unit that mixes the combustion gas and the fuel with the air-fuel ratio in a range that does not completely burn and a range in which soot is not generated as much as possible to a range near a region where complete combustion is performed, and supplies the mixture to the burner; A cooling roll heated by a flame from the burner or a surface opposite to the surface of the metal strip to which the flame is directly contacted is wound and contacted; and provided near the burner and the cooling roll. Means for immersing the surface of the metal strip continuously passed through the cleaning strip into a cleaning liquid and dewing the vapor of the cleaning liquid to condense the cleaning, thereby cleaning the metal strip.