JPS59200774A - Pretreating device for descaling of stainless steel - Google Patents

Abstract

PURPOSE:To improve efficiency in descaling and the quality of a stainless steel strip after a pickling treatment by ejecting acceleratively the uniform fine particles of an atomized aq. alkali soln. to the high-temp. stainless steel strip after an annealing treatment and oxidizing the same thereof by adjusting the distance for reaction. CONSTITUTION:A stainless steel strip 2 of a high temp. past an annealing furnace 1 is cooled to an adequate temp. with a cooler 3 and is thereafter transferred through alkali ejectors 4, 5 and a cooler 6 to a pickling device. An aq. soln. contg. an alkali such as NaOH, KOH or the like or an alkali salt such as Na or K salt of an orthosilic acid, nitrous acid, nitric acid and hydrochloric acid in a tank 7 is supplied by a pump 9 to an atomizer 12, where the soln. is atomized by inflow air 13 to uniform and fine particles. The atomized particles are then accelerated by an accelerator 15 such as fan and are sprayed from the ejecting bodies 18, 19 of the ejectors 4, 5. The length of a reaction zone 34 formed of the freely expandable cylindrical hood 33 between the bodies 18, 19 and evacuating ducts 25, 26 is adjusted to oxidize the scale, thereby providing the easily descalable state.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in a pretreatment method and apparatus for descaling stainless steel strip in continuous annealing and pickling of Nutenle 7-steel.

1. Particularly in continuous annealing and pickling of belts, the surface of the stainless steel, which is still at temperature after annealing, is treated with alkalis such as caustic soda and caustic potash.
Or alkaline salts such as sodium or potassium salts of orthosilicic acid, nitrous acid, nitric acid, or chloric acid, [by treating the aqueous solution of 1 with Nuprey to utilize the self-retention heat of the stainless steel, and applying alkali or alkali salts on the surface of the stainless steel. 1/ A means to facilitate H (descaling by reacting potassium salt for a certain period of time and forming a film from the scale formed on the surface) at a temperature above the melting point was proposed in Japanese Patent Publication No. 53-34167. has been
FIG. 1 shows an embodiment of the present invention.

Conventionally, as a spray device using this means, a spraying body (4
') '! The alkaline aqueous solution (8) suctioned and pressurized by the pump (9) is atomized using compressed air (6') by the pneumatic aging device (5') and sprayed onto the upper and lower surfaces of the stainless steel. However, the exhaust gas is sucked by an exhaust device (not shown) through the two F (7') and the exhaust duct (8') and is discharged to the atmosphere. However, in the above-mentioned spray equipment, the size of the atomized water bath liquid particles varies over a very wide range, from several microns to 200 to 600 microns. When it happens, it's a swamp.

The large particles of the aqueous solution scattered into the vortex part cause a strong weighting reaction, and after the subsequent pickling treatment, white spots from overpickling appear on the stainless steel surface, resulting in a deterioration in the quality of the finished plate, which is a problem. In the above device, in order to atomize the alkaline aqueous solution into extremely uniform and uniform particles, the nozzle diameter or slit size is made small (e.g. 7, in the case of a lift type nozzle, the slit width is approximately 0.1 mm), and it is necessary to maintain the injection pressure to the nozzle, which results in severe scattering of water-soluble particles on the stainless steel surface. As mentioned above, alkali accumulates on the nozzle tip due to radiation due to the heat retained in the stainless steel, and as mentioned above, the nozzle
Since the slit size of the nozzle is small and the nozzle often becomes clogged, it is necessary to set the nozzle tip position at a distance of, for example, 600 to 600 mm from the surface of the object to be sprayed.
It is necessary to install it once. It is necessary to deal with various types of processing stainless steel (corresponding to the reaction time 111)
Exhaust duct (8') to ensure a reliable reaction; 1).
is a sufficient distance of 1g1 from the chanting height (4') (Q
”, for example 6 to 4 meters. ) and set ii
'i will be done. Based on the above, the example shown above has a low level of adhesion of alkaline water-soluble Juniwa to the stainless steel surface, and a decrease in the exhaust suction effect, which causes water bathing particles to scatter outside the line from the hood opening. There were disadvantages such as descaling/L/efficiency reduction and enrichment of the cropping environment.

In order to eliminate the above-mentioned drawbacks, the present invention aims to solve the above-mentioned drawbacks by using an alkaline aqueous solution.
Uniformly and with an ultrasonic materialization device etc.
After shaving (after atomizing into single particles, the alkaline aqueous solution is sucked and accelerated by an accelerator such as a fan, and sprayed onto the surface of the stainless steel, and the maximum reaction time of each type of treated steel is Adjust the reaction distance 1 as appropriate and set it to 1 on the scale.
Nucleation is performed, and the exhaust suction tact near the injection position 1M is followed by the optimal reaction distance of the QiJ processing steel building.1.
+ <The device is intended to provide effective exhaust.

Hereinafter, an embodiment of the present invention will be explained in detail with reference to FIGS. 2 to 6, which show an embodiment of the present invention.

The stainless steel (2) that has passed through the annealing furnace (1) is kept at an appropriate temperature (e.g. 600 to 700°C) in the cooling device (6) on the entry side.
) is cooled to the alkaline injector IC? Ro < lIl [! will be established. The alkali or alkaline salt aqueous solution (hereinafter referred to as alkaline aqueous solution) (8) in 4゛ψ+(7) is pumped through pipes (10) and (11) by a pump (9) to an ultrasonic materialization device, etc. It is supplied to the input side of the converter i'# (12).

1r installed outside the line? The alkaline water bath liquid (8) in the oxidizing device 1ii (12) is transformed into uniform and rigid particles (for example, 60 microns or less) together with the incoming air (16), and then passes through the pipe (14). For example, the pipe (16) is accelerated to a predetermined speed by the acceleration device (15) at Fan Temple.
(17), and the steel strips (2) were placed opposite each other.
The injection bodies (18) of the two-lower pair of injection devices (4) and (5), (
19) and is injected onto the upper and lower surfaces of the steel strip.

+'+iJ notation] 1tJ11, j1not (18) (19) are respectively band rule 1 (
2) Form a cylindrical body opening in a keto shape over an area wider than the plate width of the steel strip at least in the width direction of the steel strip (
The edge of the outer wall (20) on the entrance side of 2) is close to the steel strip surface and the IQ:lt L edge, and is at an acute angle (α) between the U and the strip rir+i in FIG. The edges of the inner wall (21) are hermetically joined to each other via a proximal flute joint (24) so that alkaline water bath acid mist can be uniformly sprayed onto the surface of the band & Fi.

Of course, the upper and lower parts (1
It may be 11-zukuri.

In addition, the line traveling direction (Z
) is located close to the rear part of the steel strip at an interval of 1n1 or less, and has a suction port opening in a rectangular shape in the direction of 1111. The tact (25) (26) is connected to the outlet side outer wall (27) (28) of the steel strip 1 (2) in the same way as the 1st 1M body.
The edges of the inner walls (29) and (30) are placed close to each other without contacting the surface of the steel strip, and the edges of the inner walls (29) and (30) are spaced appropriately from the steel strip so that exhaust gas can be effectively sucked. , IJ side walls (31) and (62) are attached so as to be airtightly joined to each other, similar to the above-mentioned jet body. Exhaust tact (25) (26) is as shown in the diagram (Fig. 2).
It is mounted at an appropriate acute angle (β) with respect to the i-plane.

Injector (18) (19) and exhaust duct (25) (26)
are connected to each other in an airtight manner (excluding the inlet/outlet opening of the steel strip) via a washable cylindrical hood (65) to form a reaction zone (64), and the injector or exhaust duct A pair of wheels (
35) (The illustrated example shows the case where it is installed on the upper and lower spray body sides.

) along the rail (67) fixed to the base (filter 6) to adjust the distance between them, that is, the length of the reaction zone (64). Mount it so that the height can be adjusted. It's a trench, 1ii11 electric hood (63
) is 2 minutes up or down depending on the case;! Sometimes I do. It's υ1. The air tactors (25) and (26) are each connected to an exhaust system, not shown in the figure.

With the above configuration, in order to descale stainless steel, it is necessary to move and set either the injector or the exhaust duct in the reaction zone suitable for processing 7 stainless steel building, and then accelerate Dressing f! e (15), once the alkaline water bath acid mist is applied, the band i1 (2) will always have uniform particles spread over the entire surface area, and the heat retained in the band will cause the reaction zone (64) to flow. When the oxidation reaction is carried out efficiently and uniformly within the reaction zone to facilitate descaling, the exhaust gas from one reaction zone enters the cooling bag j on the outlet side to C, and the exhaust gas within one reaction zone is efficiently descaled through the adjacent exhaust duct. It is well and completely suctioned out.

That's all nh! According to the present invention, since the alkaline aqueous solution is injected in advance into homogeneous and easily reactive particles, the dimensions of the injection nozzle are smaller than those of the conventional one. (e.g. 0.1
mm ), for example, 20 mm to 100 mm
Since it is possible to increase the injection speed to 7i11 < 1M and to reduce the injection speed to By approaching the surface of the steel strip 1 more widely, the alkali aqueous solution can be efficiently adhered to the surface of the steel strip 1, and the oxidation reaction can be carried out effectively. The length of the reaction zone can be adjusted to suit the type of steel, and at the same time, the exhaust duct can always follow the injection port close to the injection port, making the overall length of the injection device including the reaction zone short and extremely compact. Costs and line installation time can be reduced. As mentioned above, the efficiency of suctioning the exhaust gas in the reaction zone is improved, which eliminates the scattering of alkaline aqueous acid mist from the hood opening into the atmosphere. Since this can be prevented, the working environment can be improved.In fact, as mentioned above, there are many advantages such as being able to reduce equipment maintenance and inspection costs by preventing the injection port from clogging.

In addition, if the example of [11j, Figures 2 to 5] is -(ri 11 when Jpi is used for the image processing line),
It goes without saying that even if the line JfL direction 111] (Z) is aligned with the vertical force 1r11 in the vertical processing line, the present invention can be implemented with the same configuration as described above.

4. [Explanation in 1)ij of Fig. 1 tnj] Fig. 1 is a schematic explanatory diagram of a conventional descaling pretreatment device for continuous annealing and pickling of stainless steel 7-steel, and Fig. 2 - Two FIG. 6 is a schematic front cross-sectional view for explaining the descaling pretreatment apparatus of the invention, and is a view taken along the /1m-A arrow in FIG. 2.

1. 1. Plow furnace, 2 stainless steel strip, 6, 6: Cooling device 1, 4.5: Injection device 'r'7, 5/; Air compression device, 8: Alkaline water bath, 9: Pump , 12: Atomization device, 15: Accelerator, 18.19.4′: Projectile, 2
5.26.8.8': Exhaust duct, 66.7': Hood, 64: Reaction a)), a, β: Angle, Z, line progress No. 1 1: Figure 2 No. 3 (N) 1 ↓

Claims (2)

[Claims] (1) After annealing, the surface of the Nutenless steel strip in the broiling state is treated with an alkali such as caustic soda or wJ potash, or an alkali such as silicic acid, nitrous, nitric acid, sodium or potassium salts of chlorate, etc. a) After treating the Recari salt water bath liquid with Nuprey treatment and reacting the alkali or alkali J, 1.; on the table (1) according to the possession of the stainless steel at a temperature of 1 point or higher in the bath for a predetermined period of time, human In the continuous annealing and pickling of stainless steel strips to temporalize and descale the scale generated in the process, the alkaline water bath is atomized into uniform particles, and then the alkaline water bath is accelerated to form P. ]
; Injection treatment on the stainless steel surface listed in J, and the reaction corresponding to each 8i17 treatment type +1:'i 1f:l A pre-treatment device for descaling stainless steel, which is characterized by having means for exhausting the air. (2) MjJ Special Jvf Claims Paragraph 1) I
In our stainless steel descaling pretreatment equipment, -
1J: A cylinder provided with means for wedging the alkaline water bath liquid and means for accelerating the alkaline water bath liquid, and opening in the width direction of the stainless steel along the line traveling direction over an area wider than at least the width of the stainless steel plate. a shaped projectile;
At least the above-mentioned 9 at the rear of the jet in the line traveling direction.
The exhaust ducts having suction ports opening in the stainless steel handling direction 11'lJ are placed close to each other over an area wider than the opening width of the agent body, and the distance between the two can be set freely. a pair of injection devices rdl connected through the stainless steel injection surface, and
A descaling apparatus for stainless steel, characterized in that the apparatuses i'll are arranged opposite to each other so as to be close to the opposing blasting jets l.