CN105431574A - Method for pickling high-chrome ferritic stainless steel - Google Patents
Method for pickling high-chrome ferritic stainless steel Download PDFInfo
- Publication number
- CN105431574A CN105431574A CN201480043240.8A CN201480043240A CN105431574A CN 105431574 A CN105431574 A CN 105431574A CN 201480043240 A CN201480043240 A CN 201480043240A CN 105431574 A CN105431574 A CN 105431574A
- Authority
- CN
- China
- Prior art keywords
- pickling
- stainless steel
- acid
- cold rolled
- chromium content
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
- C25F1/00—Electrolytic cleaning, degreasing, pickling or descaling
- C25F1/02—Pickling; Descaling
- C25F1/04—Pickling; Descaling in solution
- C25F1/06—Iron or steel
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
- C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
- C23G1/08—Iron or steel
- C23G1/081—Iron or steel solutions containing H2SO4
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
- C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
- C23G1/08—Iron or steel
- C23G1/086—Iron or steel solutions containing HF
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
Abstract
The present invention relates to a method for pickling high-chrome ferritic stainless steel, and more specifically, provides a method for pickling a high-chrome ferritic stainless cold-rolled plate, the method comprising: an electrolytic pickling step of subjecting a high-chrome ferritic stainless cold-rolled plate containing 17-26 wt% of chrome to neutral salt electrolytic pickling and sulfuric acid electrolytic pickling; and a mixed acid soaking step of soaking the cold-rolled plate, which has been subjected to the electrolytic pickling step, in a mixed acid solution containing sulfuric acid and hydrofluoric acid, wherein, in the electrolytic pickling step, the amount of applied current is controlled depending on the annealing temperature, and in the mixed acid soaking step, the content of free HF contained in the mixed acid solution and the oxidation-reduction potential (ORP) are controlled depending on steel components.
Description
Technical field
The present invention relates to the high speed acid washing method of the cold rolling high chromium content ferrite stainless steel plate for needing great surface quality, more specifically, relate to the method effectively being removed the anneal oxidation skin (annealingscale) be present on cold rolling high chromium content ferrite stainless steel plate by following steps: according to the components system of annealing temperature and steel grade, regulate the amount of the electric current applied in electrolytic pickling cold rolling high chromium content ferrite stainless steel plate process; When cold rolling high chromium content ferrite stainless steel plate immerses in mixed acid solution, control content and the redox potential thereof of free hydrofluoric acid in mixed acid solution; And pickling and cold-rolling high chromium content ferrite stainless steel plate.
Background technology
Usually, according to the chromium content of ferritic stainless steel, low chrome ferritic stainless steel and high chromium content ferrite stainless steel is divided into.Usually, when chromium content is 11-14wt%, ferritic stainless steel refers to low chrome ferritic stainless steel, and when chromium content is 17-26wt%, ferritic stainless steel refers to high chromium content ferrite stainless steel.
Because when carrying out thermal anneal process, the feature of the oxide skin of formation changes according to stainless chromium content, therefore, acid washing method should change according to chromium content.Usually, in low chrome ferritic stainless steel situation, relatively thick oxide skin can be formed thereon when the thermal anneal process of low chrome ferritic stainless steel; Compared with low chrome ferritic stainless steel, in high chromium content ferrite stainless steel situation, the oxide skin of relative thin can be formed thereon when the thermal anneal process of high chromium content ferrite stainless steel.
In addition, according to the feature of steel, there are differences between thermal treatment temp when steel is annealed; When annealing temperature raises, the oxide skin that steel is formed is thicker, and in oxide skin, the content of chromium may increase.
Meanwhile, because oxide skin may cause the patience deterioration to the corrosion caused by oxide skin (oxidescale), and the deterioration of product appearance quality, so need to remove the oxide skin formed on steel surface in acid cleaning process.
Usually, when manufacturing cold rolled stainless steel sheet, carry out various method, such as comprise and scrubbing or the physics de-scaling (physicaldescaling) of shot peening, use the electrolysis de-scaling (electrolyticdescaling) of sodium sulfate, sulfuric acid or nitric acid electrolytic solution, or use the chemical de-scaling (chemicaldescaling) of salt bath or acid mixture, to obtain great surface quality by removing the oxide skin formed on cold rolled stainless steel sheet and to increase the solidity to corrosion of steel plate.Such process is referred to as acid cleaning process.
Such acid cleaning process has two stages: the first operation carrying out electrolytic pickling process, such as electrolysis de-scaling; With the second step carrying out the dipped journey of mixing acid, such as chemical de-scaling.
By this way, the process by using the mixed acid solution comprising the nitric acid of 80-180g/l and the hydrofluoric acid of 2-40g/l to carry out pickling and cold-rolling stainless steel plate.Here, the effect of the nitric acid contained by mixed acid solution is, pH in reduction pickling tank to increase the activity of hydrofluoric acid, and makes from iron (II) ionic oxide formation of cold rolled stainless steel sheet surface dissolution to be that iron (III) ion is to maintain the redox potential being suitable for pickling.But nitric acid produces controlled air pollutant NO
x, and comprise a large amount of nitric nitrogen NO from its spent acid produced and waste water
3-N.
Therefore, due to the country that strengthens and international environment regulation, to NO in total allowance of nitrogen in the effluent of the discharge from production facility and discharge
xthe restriction of concentration, need install in acid cleaning process equipment and operate extra Pollution treatment installation.Operate so extra Pollution treatment installation and may relate to high cost, therefore, also significantly increase the unit cost of product.
Therefore, in order to address these problems, propose and substituting with hydrochloric acid or sulfuric acid the method being contained in nitric acid in mixed acid solution used in traditional acid cleaning process.But in this case, because the oxidation of mixed acid solution is relatively low, therefore the dissolution rate of oxide skin is low, and in dissolution process, metallic surface may be dimmed.
So, in order to reach the open circuit potential level of the steel plate acid-washing feature of the best, develop the method using hydrogen peroxide, potassium permanganate, iron (III) ion and air Injection to carry out supplemental scarce capacity, hydrogen peroxide is typically used as oxygenant, which reduces the burden to environment.
But, in this case, because determine that the suitable addition of oxygenant may be difficult, so, according to circumstances may cause the problem of underpickling or over-pickling, and the situation that surface of steel plate may be dimmed may can not be processed effectively.
Simultaneously, United States Patent (USP) the 5th, 908, No. 511 propose a technology: use sulfuric acid, hydrofluoric acid and molysite to carry out pickling, regular interpolation hydrogen peroxide, regulate the composition of such as wetting agent, rumbling compound or stopping agent etc., and manage Acidwash solution in the mode automatically controlling iron (III) and its corresponding redox potential (ORP).
The Acidwash solution of this United States Patent (USP) business turns to CLEANOX352, be the most widely used acid washing method in the world, and the acid washing method of this U.S. Patent Publication is realized completely in process wire rod and hot-rolled product.
Here, the problem of the acid washing method of this United States Patent (USP) is, the unit cost of products production, than traditional method height about 20%, have employed complicated liquid composite and complicated management process, and it is crucial that, due to 1.5-3g/m
2the pickling speed of min is relatively low, and this acid washing method is not suitable for the high speed pickling line needing to complete mixing acid pickling within 10-100 second.
Therefore, European patent discloses No. 1040211 and No. 2000-560982nd, U.S. Patent Publication and proposes by adding cupric ion and chlorion increases the method for pickling speed as the improvement to above-mentioned United States Patent (USP) in acid cleaning composition.But, the method is problematic, because when the open circuit potential formed on the surface at ferrite stainless steel (OCP) be less than 0.1V be namely in equal level with the redox potential of cupric ion time, because cupric ion may be gone out from ferrite stainless steel surface extraction in acid cleaning process, so ferrite stainless steel may fade, and when the chlorion comprised in Acidwash solution is predetermined concentration or more, the risk of spot corrosion may be there is.
Summary of the invention
Technical problem
One aspect of the present invention can provide does not have residual oxide skin and the stainless steel plate with outstanding surface gloss.
One aspect of the present invention also can when steel plate immerses mixed acid solution, by preventing surface of steel plate not by pickling, over-pickling or dimmed according to oxidation reduction potential determination to be input to the appropriate amount of the hydrogen peroxide in mixed acid solution.
One aspect of the present invention is not by using nitric acid to reduce the burden of process waste water and waste gas yet in mixed acid solution used in steel plate acid-washing process.
Technical scheme
According to an aspect of the present invention, the method of pickling high chromium content ferrite cold rolled stainless steel sheet can comprise: electrolytic pickling operates, and uses neutral salt and sulfuric acid to carrying out electrolytic pickling being equal to or greater than the high chromium content ferrite cold rolled stainless steel sheet comprising 17-26wt% chromium of annealing under 1030 DEG C to the annealing temperature being equal to or less than 1050 DEG C; And mixing acidleach operation, being immersed by the high chromium content ferrite cold rolled stainless steel sheet of electrolytic pickling comprises in the mixed acid solution of sulfuric acid and hydrofluoric acid, wherein in electrolytic pickling operation, the amount of the electric current applied in neutral salt electrolysis acid cleaning process and the summation of the amount of electric current applied in sulphuric acid electrolyte acid cleaning process are controlled as being equal to or greater than 12A/dm
2and be equal to or less than 20A/dm
2.
According to another aspect of the present invention, the method of pickling high chromium content ferrite cold rolled stainless steel sheet can comprise: electrolytic pickling operates, and uses neutral salt and sulfuric acid to being equal to or greater than 930 DEG C and the high chromium content ferrite cold rolled stainless steel sheet comprising 17-26wt% chromium of annealing under being less than the annealing temperature of 1030 DEG C carries out electrolytic pickling; And mixing acidleach operation, being immersed by the high chromium content ferrite cold rolled stainless steel sheet of electrolytic pickling comprises in the mixed acid solution of sulfuric acid and hydrofluoric acid, wherein in electrolytic pickling operation, the amount of the electric current applied in neutral salt electrolysis acid cleaning process and the summation of the amount of electric current applied in sulphuric acid electrolyte acid cleaning process are controlled as being equal to or greater than 30A/dm
2to being equal to or less than 50A/dm
2.
The amount of the electric current applied in neutral salt electrolysis acid cleaning process can be equal to or greater than 8A/dm
2, the amount of the electric current applied in sulphuric acid electrolyte acid cleaning process can equal 0, or is equal to or greater than 8A/dm
2.
Based on the gross weight of high chromium content ferrite cold rolled stainless steel sheet, when silicon (Si) content is equal to or less than 0.3wt% or molybdenum (Mo) content is equal to or less than 0.5wt%, the mixed acid solution used in mixing acidleach operation can comprise the sulfuric acid of 80-150g/l and the free hydrogen fluoric acid of 5-12g/l, and can have the redox potential (ORP) being equal to or greater than 550mV.
Can hydrogen peroxide be joined in mixed acid solution, remain on to make the redox potential of mixed acid solution (ORP) level being equal to or greater than 550mV.
Based on the gross weight of high chromium content ferrite cold rolled stainless steel sheet, when silicon (Si) content is greater than 0.3wt% or molybdenum (Mo) content is greater than 0.5wt%, the mixed acid solution used in mixing acidleach operation can comprise the sulfuric acid of 80-150g/l and the free hydrogen fluoric acid of 20-30g/l, and can have the redox potential (ORP) being equal to or greater than 320mV.
Can hydrogen peroxide be joined in mixed acid solution, be equal to or greater than the level of 320mV to make the redox potential of mixed acid solution remain on.
The electrolytic solution comprising 100-250g/l sodium sulfate can be used to carry out neutral salt electrolysis pickling.
The temperature of the electrolytic solution used in neutral salt electrolysis pickling can be 50 DEG C-90 DEG C.
Neutral salt electrolysis pickling can carry out 24-100 second.
The electrolytic solution of sulfuric acid or the metal sulfate comprising 50-150g/l can be used to carry out sulphuric acid electrolyte pickling, and wherein said metal sulfate is by being formed at least one dissolving metal in chosen from Fe, chromium, nickel, copper, manganese and titanium in the sulfuric acid of 50-150g/l.
The temperature of the electrolytic solution used in sulphuric acid electrolyte pickling can be 30 DEG C-60 DEG C.
Sulphuric acid electrolyte pickling can carry out 10-50 second.
Mixing acidleach operation can carry out 25-90 second.
In mixing acidleach operation, the open circuit potential of high chromium content ferrite cold rolled stainless steel sheet can remain on the level of-0.2V to 0V.
Beneficial effect
According to exemplary of the present invention, can provide and there is no residual oxide skin and the cold rolling high chromium content ferrite stainless steel plate with outstanding surface gloss.
In addition, according to exemplary of the present invention, when steel plate immerses mixed acid solution, by preventing surface of steel plate not by pickling, over-pickling or dimmed according to oxidation reduction potential determination to be input to the appropriate amount of the hydrogen peroxide in mixed acid solution.
In addition, according to exemplary of the present invention, by not using nitric acid to reduce the burden of process waste water and waste gas in mixed acid solution used in steel plate acid-washing process.
Accompanying drawing explanation
Fig. 1 illustrates according to each 439 steel and the Cr content of anneal oxidation skin thickness of 441 steel and the schematic diagram of the ratio of Fe content;
Fig. 2 is the schematic diagram according to the neutral salt electrolysis groove of the electrolytic pickling carried out of annealing temperature and the applied current region of sulphuric acid electrolyte groove;
Fig. 3 is silicone content according to comprising in cold-rolled steel sheet and molybdenum content, the schematic diagram in the free hydrofluoric acid concentration comprised in the mixed acid solution used in mixing acidleach operation and the redox potential region of mixed acid solution;
Fig. 4 (a)-4 (d) is the view that its surface after the acid-washing stainless steel in comparative example 1, embodiment 1, comparative example 8 and comparative example 9 is described respectively;
Fig. 5 (a)-5 (c) is the view that its surface after the acid-washing stainless steel in comparative example 16, embodiment 6 and comparative example 28 is described respectively;
Fig. 6 (a) and 6 (b) are the views that its surface after the acid-washing stainless steel in comparative example 29 and comparative example 31 is described respectively;
Fig. 7 (a) and 7 (b) are the views that its surface after the acid-washing stainless steel in comparative example 32 and embodiment 16 is described respectively;
Fig. 8 (a) and 8 (b) are the views that its surface after the acid-washing stainless steel in comparative example 33 and embodiment 19 is described respectively.
Embodiment
Hereinafter, embodiment of the present invention are described in detail with reference to accompanying drawing.But the present invention can illustrate in many different forms, and should not be understood to be limited to specific embodiments in this paper.
The present invention relates to pickling high chromium content ferrite cold rolled stainless steel sheet to remove the method for the oxide skin that high chromium content ferrite cold rolled stainless steel sheet surface exists, described high chromium content ferrite cold rolled stainless steel sheet comprises the chromium based on high chromium content ferrite cold rolled stainless steel sheet gross weight 17-26wt%; More specifically, relate to the method for pickling high chromium content ferrite cold rolled stainless steel sheet, the method comprises: electrolytic pickling operates, and uses neutral salt and sulphuric acid electrolyte pickling high chromium content ferrite cold rolled stainless steel sheet; And mixing acidleach operation, being immersed by the high chromium content ferrite cold rolled stainless steel sheet of electrolytic pickling comprises in the mixed acid solution of sulfuric acid and hydrofluoric acid, wherein according to the levels of current of application in the annealing temperature control acidleach operation in electrolytic pickling operation, and according to mixing the content of free hydrogen fluoric acid (HF) and the redox potential (ORP) of mixed acid solution that comprise in the component control mixed acid solution of steel in acidleach operation.
In acid washing method of the present invention, high chromium content ferrite cold rolled stainless steel sheet sequentially can experience neutral salt electrolysis pickling in electrolytic pickling method and sulphuric acid electrolyte pickling.
Now, the electrolytic solution comprising 100-250g/l sodium sulfate can be used to carry out neutral salt electrolysis pickling, particularly, cold-rolled steel sheet is immersed temperature be in the electrolytic solution of 50 DEG C-90 DEG C after, by application 8-30A/dm
2the electric current 24-100 second of level, make the current potential of surface of cold-rolled steel plate at least once charged with positive and negative, positive order.
In addition, sulphuric acid electrolyte pickling can use the electrolytic solution comprising 50-150g/l sulfuric acid or metal sulfate to carry out, and described metal sulfate is formed by being dissolved in the sulfuric acid of 50-150g/l by least one electrochemical metal in chosen from Fe (Fe), chromium (Cr), nickel (Ni), copper (Cu), manganese (Mn) and titanium (Ti); Particularly, cold-rolled steel sheet is immersed temperature be in the electrolytic solution of 30 DEG C-60 DEG C after, by application 0-30A/dm
2current density 10-50 second, make the current potential of surface of cold-rolled steel plate at least once charged with positive and negative, positive order.
Meanwhile, when high chromium content ferrite stainless steel, in the oxide skin produced when annealing high chromium content ferrite stainless steel, chromium content is high, and particularly, annealing temperature is higher, and chromium content becomes higher.Now, when the chromium content comprised in oxide skin becomes higher, the easily dissolved oxygen compound when neutral salt electrolysis pickling high chromium content ferrite stainless steel.Such as, when annealing temperature is equal to or greater than 1030 DEG C, chromium is excessively concentrated, thus under the condition of the high current applied when neutral salt electrolysis pickling and sulphuric acid electrolyte pickling, may there is the over-pickling because surface dissolution causes.
Therefore, according to exemplary of the present invention, to be equal to or greater than 1030 DEG C and the cold-rolled steel sheet of annealing at the relatively high temperature being equal to or less than 1050 DEG C carries out electrolytic pickling when, when the amount of the electric current applied in neutral salt electrolytic pickling and the summation of the amount of electric current applied in sulphuric acid electrolyte pickling are less than 12A/dm
2time, may underpickling be there is, and when summation is greater than 20A/dm
2time, the surface roughening caused by over-pickling may be there is.In order to effective pickling, can preferably the summation of the amount of the electric current applied in the amount of the electric current applied in neutral salt electrolysis acid cleaning process and sulphuric acid electrolyte acid cleaning process be controlled as being equal to or greater than 12A/dm
2to being equal to or less than 20A/dm
2.
Simultaneously, according to another exemplary of the present invention, to be equal to or greater than 930 DEG C and the cold-rolled steel sheet of annealing at the relatively low temperature being less than 1030 DEG C carries out electrolytic pickling when, may underpickling be there is, and when the summation of the amount of the amount of electric current applied in neutral salt electrolytic pickling and the electric current applied in sulphuric acid electrolyte pickling is less than 30A/dm
2time, may underpickling be there is, and when summation is greater than 50A/dm
2time, the surface roughening caused by over-pickling may be there is.In order to effective pickling, can preferably the summation of the amount of the electric current applied in the amount of the electric current applied in neutral salt electrolysis acid cleaning process and sulphuric acid electrolyte acid cleaning process be controlled as being equal to or greater than 30A/dm
2to being equal to or less than 50A/dm
2.
Only, in the present invention, can preferably no matter electrolytic pickling time annealing temperature how, the magnitude of current applied in neutral salt electrolysis acid cleaning process is for being equal to or greater than 8A/dm
2, the amount of the electric current applied in sulphuric acid electrolyte acid cleaning process is 0 or is equal to or greater than 8A/dm
2.
Particularly, when the amount of the electric current applied in neutral salt electrolytic pickling process is less than 8A/dm
2time, do not form the open circuit potential of solubilized anneal oxidation skin, the effect of neutral salt electrolysis pickling thus may be very weak.Therefore, in order to dissolve enough oxide skin, the amount of the electric current that can preferably apply is for being equal to or greater than 8A/dm
2.
In addition, when the amount of the electric current applied in sulphuric acid electrolyte acid cleaning process is greater than 0 and is less than 8A/dm
2time, the uneven and coarse problem in surface may occur, and in order to the surface of even pickled plate, the amount of the electric current that can preferably apply in sulphuric acid electrolyte acid cleaning process is 0 or is equal to or greater than 8A/dm
2.
Only, the amount of the electric current applied in sulphuric acid electrolyte acid cleaning process is 0A/dm
2meaning, when dissolving a large amount of anneal oxidation skin in the neutral salt electrolysis pickling before sulphuric acid electrolyte pickling operation, in order to prevent the destruction to base metal, can immerse when not needing applied current.
In addition, about the upper limit of the levels of current applied in neutral salt electrolysis acid cleaning process and sulphuric acid electrolyte pickling, higher limit can be determined by the summation of the levels of current applied two kinds of electrolytic picklings, but is not limited to certain value.In view of the consideration of economic aspect such as operation cost etc., such as, the upper limit of the levels of current that can preferably apply is for being equal to or less than 30A/dm
2.
Fig. 2 is the figure in the region illustrated to neutral salt electrolysis groove and sulphuric acid electrolyte groove applied current, wherein can carry out electrolytic pickling according to annealing temperature.The region I of Fig. 2 describes the scope of the electric current applied to neutral salt electrolysis groove and sulphuric acid electrolyte groove, can be wherein carry out electrolytic pickling in the region of 1030 DEG C-1050 DEG C in the annealing temperature of the ferritic stainless steel comprising 17-26wt% chromium.Region II describes the scope of the electric current applied to neutral salt electrolysis groove and sulphuric acid electrolyte groove, wherein can be equal to or greater than 930 DEG C in annealing temperature and be equal to or less than in the region of 1030 DEG C and carry out electrolytic pickling.
In the present invention, when carrying out electrolytic pickling, chromium and iron oxide layer that the surface of high chromium content ferrite cold rolled stainless steel sheet exists can be removed, but the silicon dioxide layer on it can retain.Therefore, acid washing method of the present invention can remove by carrying out mixing acid leaching operation after electrolytic pickling operation the silicon dioxide layer remained on high chromium content ferrite cold rolled stainless steel sheet, and described mixing acidleach operation is immersed by the high chromium content ferrite cold rolled stainless steel sheet of electrolytic pickling to comprise in the mixed acid solution of sulfuric acid and hydrofluoric acid.
As shown in the formula (1), can be mixed acid solution by hydrofluoric acid (HF) ionization comprised in the mixed acid solution used in mixing acidleach operation, such as formula (2), the hydrogen ion (H provided by ionization sulfuric acid
+) concentration, i.e. acidity, can change the equilibrium state of mixed acid solution.
Here, in free hydrogen fluoric acid (HF) unionized state, hydrofluoric acid can have pickling ability, and such free hydrogen fluoric acid can through the interface of silicon-dioxide and base metal and dissolve silica and iron (Fe), then can such as FeF
x (3-x)or H
2siF
6the silicon ion of form and dissolving and iron ion be combined, these can remove from the surface of high chromium content ferrite cold rolled stainless steel sheet thus.
Therefore, preferably the mixed acid solution with 5-30g/l free hydrogen fluoric acid can be used in mixing acidleach operation.When free hydrogen fluoric acid is less than 5g/l, the problem to high chromium content ferrite cold rolled stainless steel sheet surface acid-washing deficiency may be caused to the solvency power deficiency of silicon dioxide layer; When free hydrogen fluoric acid is greater than 30g/l, the dissolution rate of base metal may be increased, thus after pickling, the surface of high chromium content ferrite cold rolled stainless steel sheet may become coarse.
As mentioned above, the hydrofluoric acid comprised in mixed acid solution can provide can from the pickling ability of the surface removing silicon dioxide layer of high chromium content ferrite cold rolled stainless steel sheet, but need the free hydrofluoric acid concentration of remaining valid to have acidity more higher levels of than the predeterminated level of mixed acid solution.Therefore, in order to make the hydrofluoric acid comprised in mixed acid solution not be ionized, there is sulfuric acid that is predetermined or greater concn and preferably can be contained in mixed acid solution together with hydrofluoric acid.
Now, the suitable concn of sulfuric acid can be preferably 80-150g/l, and when the concentration of sulfuric acid is less than 80g/l, the free hydrofluoric acid concentration that can not remain valid is with ionized hydrogen fluoric acid, thus pickling reduced capability, cause the problem of underpickling thus.When the concentration of sulfuric acid is greater than 150g/l, the problem etc. producing heat when dilute sulphuric acid may be there is, thus be difficult to dilute sulphuric acid.
Meanwhile, the silicon-dioxide in the oxide skin of ferritic stainless steel can be present on the crystal boundary between the grain surface of all ferrite crystal and crystal grain, and the silicon-dioxide on crystal boundary can be present in the more depths in base metal.Owing to having the crystal of high non-fusibility (dissolutionresistance), therefore when making austenitic stainless steel coarse by first dissolving the crystal boundary of austenitic stainless steel, ferritic stainless steel has low corrosion proof crystal, there is no difference between dissolution rate in ferritic stainless steel crystal and the dissolution rate between its crystal boundary thus, thus the surface of ferrite stainless crystalline grain of steel and crystal boundary thereof optionally do not dissolve completely.Therefore, in order to remove all silicon-dioxide, need the base metal dissolving considerable part.
Now, Fe
2+can from base metal wash-out, when with oxygenant as hydroperoxidation time, the Fe of wash-out
2+fe can be oxidized to
3+, then can be combined with free hydrogen fluoric acid, to produce, there is FeF
x (3-x)the complex compound of form, removes from the surface of high chromium content ferrite cold rolled stainless steel sheet thus.This reaction can as shown in the formula shown in (3)-(6), and such process should steadily carry out improving pickling speed.
Fe
0→Fe
2++2e
-(3)
Fe
2++H
2O
2→Fe
3++OH·+OH
-(4)
Fe
3++3HF→FeF
3+3H
+(5)
Cu
2++2e
-→Cu
0(6)
Now, when the concentration of hydrogen peroxide in mixed acid solution is not enough, the reaction of formula (4) can not be carried out, thus the Fe on high chromium content ferrite cold rolled stainless steel sheet surface
2+concentration local increase, the reaction on formula (3) left side can become main thus.In this case, shown in (6), Fe or Cu be present in ferritic stainless steel as additive or impurity is extracted again by the surface from high chromium content ferrite cold rolled stainless steel sheet, thus may be dimmed, thus the surface of high chromium content ferrite cold rolled stainless steel sheet is dimmed.Therefore, the content of hydrogen peroxide preferably can be made to remain on predeterminated level thus fully can carry out the reaction of formula (4).
Meanwhile, as mentioned above, when by when immersing mixed acid solution until the high chromium content ferrite cold rolled stainless steel sheet of pickling, even may remove and dissolve part of substrate metal and residual silicon dioxide layer thereon.In ferritic stainless steel, molybdenum content is higher, and its solidity to corrosion is higher, and dissolution rate when can reduce pickling.Silicon (Si) content is higher, and silicon dioxide layer is thicker, and therefore mixed acid solution may be difficult to dissolve base metal.
Therefore, in mixing acidleach operation, according to the silicon comprised in high chromium content ferrite cold rolled stainless steel sheet (Si) content and molybdenum (Mo) content, by regulating content and the redox potential (ORP) thereof of the free hydrogen fluoric acid (HF) comprised in mixed acid solution, acid washing method of the present invention can carry out pickling effectively.
Such as, when high chromium content ferrite stainless steel, when silicon (Si) content is equal to or less than 0.3wt% or molybdenum (Mo) content is equal to or less than 0.5wt%, most of anneal oxidation skin can be removed in electrolytic pickling operation, and only can remove a small amount of residual silicon-dioxide.The dissolving of base metal can be minimized preferably by the concentration of reduction free hydrogen fluoric acid.
Therefore, in the present invention, when silicon (Si) content is equal to or less than 0.3wt% or molybdenum (Mo) content is equal to or less than 0.5wt%, mixed acid solution preferably can comprise the sulfuric acid of 80-150g/l and the hydrofluoric acid of 5-12g/l, and there is the hydrogen peroxide of interpolation, with the level making the redox potential of mixed acid solution (ORP) maintain 550mV or higher, to prevent dimmed.
On the other hand, when silicon in high chromium content ferrite stainless steel (Si) content is greater than 0.3wt%, before mixing acidleach operation and after electrolytic pickling high chromium content ferrite cold rolled stainless steel sheet, can there is a large amount of silicon-dioxide in high chromium content ferrite cold rolled stainless steel sheet surface.In order to effectively remove silicon-dioxide, the free hydrogen fluoric acid with high density preferably can be used.
In addition, when molybdenum in high chromium content ferrite stainless steel (Mo) content is greater than 0.5wt%, because the molybdenum content comprised in high chromium content ferrite cold rolled stainless steel sheet is high, its solidity to corrosion may increase, obviously can reduce the dissolution rate of mixed acid solution to base metal thus, so, can preferably use the mixed acid solution comprising high density free hydrogen fluoric acid.
Therefore, in the present invention, when silicon (Si) content is greater than 0.3wt% or molybdenum (Mo) content is greater than 0.5wt%, mixed acid solution preferably can comprise the sulfuric acid of 80-150g/l and the free hydrogen fluoric acid of 20-30g/l, and there is the hydrogen peroxide of interpolation, with the level making the redox potential of mixed acid solution (ORP) maintain 320mV or higher, to prevent dimmed.
Only, in acid washing method of the present invention, how are the silicon no matter comprised in ferritic stainless steel and molybdenum content, the upper limit of the redox potential range specifically limiting mixed acid solution can not be needed, but when using the hydrofluoric acid of high density, the metal content in mixed acid solution can become very high usually.Amount due to the hydrogen peroxide added in this case is too much to maintain high redox potential, therefore may there is the problem of economic point of view, so preferably the upper limit can be maintained the level being equal to or less than 600mV.
Fig. 3 illustrates silicon according to comprising in cold-rolled steel sheet and molybdenum content, the figure in the region of the redox potential of the free hydrofluoric acid concentration that the mixed acid solution used in mixing acidleach operation comprises and mixed acid solution.
Particularly, the region III explanation of Fig. 3, when to comprise have Si content be equal to or less than high chromium content ferrite stainless steel that 0.3wt% and Mo content is equal to or less than the stainless steel component of 0.5wt% carry out electrolytic pickling then immersed mixed acid solution time, the concentration can carrying out the free hydrogen fluoric acid of pickling is 5-12g/l, and the redox potential of mixed acid solution is 550mV or higher.
In addition, the region IV explanation of Fig. 3, when to comprise have Si content be greater than high chromium content ferrite stainless steel that 0.3wt% and Mo content is greater than the stainless steel component of 0.5wt% carry out electrolytic pickling then immersed in mixed acid solution time, the concentration can carrying out the free hydrogen fluoric acid of pickling is 20-30g/l, and the redox potential range of mixed acid solution is 320mV or higher.
Preferably the open circuit potential of high chromium content ferrite cold rolled stainless steel sheet can be maintained the level of-0.2V to 0V.Stainless dissolution rate and pattern (pattern) can be measured according to open circuit potential.When the low value of open circuit potential is less than-0.2V, base metal mainly can be dissolved as Fe
2+and and SO
4 2-react to form FeSO on the surface of high chromium content ferrite cold rolled stainless steel sheet
4compound, thus surface can be made dimmed.In this case, when dissolving base metal, the direction excessive dissolution that the crystal grain of base metal can be certain, thus surface can become very coarse, because not have the Fe that elimination only can remove when open circuit potential height
3+, over-pickling and underpickling also may and deposit.On the other hand, when open circuit potential is more than 0V, too highly variable in the prepotential of dissolving surface, thus in fact need to remove its unwanted part by dissolving to remain, therefore significantly can reduce pickling speed.Because in order to the high open circuit potential maintaining high chromium content ferrite cold rolled stainless steel sheet in sulfuric acid-hydrofluoric acid-hydrogen peroxide system, hydrogen peroxide consumption becomes very high, so may there are economic problems.
In the present invention, the time of implementing mixing acidleach manipulation require is unrestricted, but can change according to operational condition.Acid washing method of the present invention can allow within the relatively short time of 25-90 second, carry out mixing acidleach operation.
Preferred forms
Hereinafter, more specifically the present invention will be described by its specific embodiments.Embodiment be below only embodiment for understanding the present invention better, scope of the present invention is not limited to these.
In the present invention, in following examples, use 441 steel and 439 steel.The statement of 441 steel and 439 steel can show the ratio of Cr content and Fe content in anneal oxidation skin.Can heat-treat 441 steel at the temperature of 1050 DEG C, can heat-treat 439 steel at 970 DEG C.In 441 steel and 439 steel, the Cr content of anneal oxidation skin and the ratio of Fe content can be respectively about 8.5 and about 4.3.
Based on each gross weight in these two kinds of steel, these two kinds of steel can comprise the chromium of about 17%, but according to the feature of these two kinds of steel, the difference between annealing temperature can make to have difference between Cr/Fe ratio in each anneal oxidation skin.
Meanwhile, neutral salt electrolysis can allow Cr
2o
3, Cr
3+oxide compound is oxidized is dissolved as Cr
6+(C
r2O
4 2-) ion, but be difficult to dissolve Fe base oxide, so chromium content is higher in anneal oxidation skin, more advantageously remove anneal oxidation skin.Therefore, owing to comprising High Content Chromium in anneal oxidation skin, all 439 steel and 441 steel are all the steel grades that can be conducive to neutral salt electrolysis pickling, but 441 steel that ratio 439 steel have the ratio of higher Cr content and Fe content may more be conducive to neutral salt electrolysis pickling.
In addition, Fig. 1 is the figure of the ratio that Cr content and Fe content in the anneal oxidation skin according to often kind of 439 steel and 441 steel are described.439 all steel and 441 steel all have the chromium content increased from the skin of anneal oxidation skin to its internal layer respectively, thus Cr/Fe is than being increase.Can find out, Cr/Fe is tending towards the Cr/Fe ratio of (convergeson) base metal than the complete inside towards base metal.
Embodiment 1-5 and comparative example 1-15
By to comprising sodium sulfate as those current densities as shown in table 1 below of application examples in the neutral salt electrolysis groove of electrolytic solution with to comprising sulfuric acid as the sulphuric acid electrolyte groove application examples of electrolytic solution those current densities as shown in table 1 below, electrolytic pickling is carried out to 441 steel with 1050 DEG C of annealing temperatures.Then, 441 steel are immersed temperature be 40 DEG C and comprise in the mixed acid solution of the sulfuric acid of 80g/l and the free hydrogen fluoric acid of 8g/l 30 seconds.Only, in mixed acid solution, add remaining 3g/l hydrogen peroxide, with the level making the redox potential of mixed acid solution maintain 550mV or higher.
The result of pickling is shown in Table 1.Do not had by surface of steel plate the situation of residual oxidization skin to be labeled as O, surface of steel plate is had the situation of residual oxidization skin be labeled as ×, be considered as underpickling.The surface roughening caused by over-pickling is also labeled as ×.
Illustrate that the view on its surface after acid-washing stainless steel in comparative example 1, embodiment 1, comparative example 8 and comparative example 9 is respectively as shown in Fig. 4 (a)-4 (d) respectively.
Table 1
(" summation " in the upper table 1 of * refers to the summation of the current density of neutral salt electrolysis pickling and the current density of sulphuric acid electrolyte pickling.)
As can be seen from Table 1, when the electric current applied to neutral salt electrolysis groove is equal to or greater than 8A/dm
2, equal 0 or be equal to or greater than 8A/dm to the electric current of sulphuric acid electrolyte groove application
2, and be equal to or greater than 12A/dm to the summation of the levels of current of two electrolyzer application
2and be equal to or less than 20A/dm
2time, the surface of normal pickling may be shown.
But, as shown in comparative example 1-5, can find out, when the electric current applied to neutral salt electrolysis groove is less than 8A/dm
2time, be dissolved in the quantity not sufficient of the oxide skin of neutral salt electrolysis groove, thus underpickling occurs; As shown in comparative example 7,9 and 12, when the current value of sulphuric acid electrolyte pickling is greater than 0 and is less than 8A/dm
2time, even if be equal to or greater than 8A/dm at the electric current applied to neutral salt electrolysis groove
2when, also can uneven pickling.
In addition, as comparative example 8,10,11,13, shown in 14 and 15, can find out, be greater than 20A/dm when the electric current applied to neutral salt electrolysis groove with to the summation of the electric current of sulphuric acid electrolyte groove application
2time, there is over-pickling.
Fig. 4 (a)-4 (d) is the view that its surface after acid-washing stainless steel in comparative example 1, embodiment 1, comparative example 8 and comparative example 9 is described respectively.Fig. 4 (a) shows underpickling because the quantity not sufficient of electric current causes and there is residual oxide skin, and Fig. 4 (b) shows the surface of the normal pickling according to embodiment 1.In addition, Fig. 4 (c) shows that unsatisfied surface that the surface roughening occurred due to over-pickling causes, Fig. 4 (d) also show the unsatisfied surface because uneven pickling causes.
By above embodiment, can find out, when the ratio height of chromium component in oxide skin component, even if to the electric current of neutral salt electrolysis groove and these two electrolyzer application low relative levels of sulphuric acid electrolyte groove, be wherein equal to or greater than 12A/dm when electrolytic pickling to the summation of the levels of current of two electrolyzers application
2and be equal to or less than 20A/dm
2, pickling also can be carried out.
Embodiment 6-12 and comparative example 16-28
By to comprising sodium sulfate as those current densities as shown in table 2 below of application examples in the neutral salt electrolysis groove of electrolytic solution with to comprising sulfuric acid as the sulphuric acid electrolyte groove application examples of electrolytic solution those current densities as shown in table 2 below, electrolytic pickling is carried out to 439 steel with 970 DEG C of annealing temperatures.Then, 439 steel are immersed temperature to be 40 DEG C and to comprise in the mixed acid solution of the sulfuric acid of 80g/l and the free hydrogen fluoric acid of 8g/l 30 seconds.Only, in mixed acid solution, add remaining 3g/l hydrogen peroxide, with the level making the redox potential of mixed acid solution maintain 550mV or higher.
The result of pickling is shown in Table 2.Do not had by surface of steel plate the situation of residual oxidization skin to be labeled as O, surface of steel plate is had the situation of residual oxidization skin be labeled as ×, be considered as underpickling.The surface roughening caused by over-pickling is also labeled as ×.
Illustrate that the view on its surface after acid-washing stainless steel in comparative example 16, embodiment 6 and comparative example 28 is respectively as shown in Fig. 5 (a)-5 (c) respectively.
Table 2
(" summation " in the upper table 2 of * refers to the summation of the current density of neutral salt electrolysis pickling and the current density of sulphuric acid electrolyte pickling.)
As can be seen from Table 2, as shown in embodiment 6-12, when the electric current applied to neutral salt electrolysis groove is equal to or greater than 8A/dm
2and be equal to or greater than 30A/dm to the levels of current of neutral salt electrolysis groove and these two the electrolyzer application of sulphuric acid electrolyte groove
2and be equal to or less than 50A/dm
2time, the surface of normal pickling may be shown.
But, as shown in comparative example 16-19, can find out, when the electric current applied to neutral salt electrolysis groove is less than 8A/dm
2time, be dissolved in the quantity not sufficient of the oxide skin of neutral salt electrolysis groove, thus underpickling occurs; As shown in comparative example 20-27, when the amount of the electric current applied to neutral salt electrolysis groove is less than 30A/dm with the summation of the amount of the electric current applied to sulphuric acid electrolyte groove
2time, even if be equal to or greater than 8A/dm at the electric current applied to neutral salt electrolysis groove
2when, also can there is underpickling.In addition, as shown in comparative example 28, can find out, when the summation of the levels of current to neutral salt electrolysis groove and these two the electrolyzer application of sulphuric acid electrolyte groove is greater than 50A/dm
2time, can over-cleaning be there is.
Fig. 5 (a)-5 (c) is the view that its surface after acid-washing stainless steel in comparative example 16, embodiment 6 and comparative example 28 is described respectively.Fig. 5 (a) shows underpickling because the quantity not sufficient of electric current of application in comparative example 16 causes and there is residual oxide skin, Fig. 5 (b) shows the surface of the normal pickling according to embodiment 6, and Fig. 5 (c) shows unsatisfied surface that the surface roughening occurred due to the over-pickling in comparative example 28 causes.
Although do not illustrate in an embodiment, be less than 8A/dm at the electric current applied to sulphuric acid electrolyte groove
2when, even if when the summation of the levels of current to neutral salt electrolysis groove and the application of sulphuric acid electrolyte groove is within the scope of normal pickling, the surface of uneven pickling can non-preferentially be shown in Fig. 4 (d).
Pass through above-described embodiment, can find out, when the ratio of chromium component is relatively low in oxide skin component, need very high-caliber applied current, wherein in electrolytic pickling, be equal to or greater than 30A/dm to the summation of the levels of current of these two electrolyzers application of neutral salt electrolysis groove and sulphuric acid electrolyte groove
2and be equal to or less than 50A/dm
2.
Embodiment 13-21 and comparative example 29-33
According to annealing temperature, carry out electrolytic pickling by the application condition consistent with the region III of Fig. 3 and region IV to the steel of steel grade listed by following table 3, then immersion temperature to comprise in the mixed acid solution of the free hydrogen fluoric acid of concentration listed by the sulfuric acid of 80g/l and following table 3 30 seconds for 40 DEG C.Only, hydrogen peroxide is joined in mixed acid solution to make the redox potential of mixed acid solution maintain value listed by following table 3 or much higher value.
The result of pickling is shown in Table 3.Do not had by surface of steel plate the situation of residual oxidization skin to be labeled as O, surface of steel plate is had the situation of residual oxidization skin be labeled as ×, be considered as underpickling.The surface roughening caused by over-pickling is also labeled as ×.
In addition, in comparative example 29 and comparative example 31, after acid-washing stainless steel, its surface view is shown in Fig. 6 (a) and 6 (b), comparative example 32 and to implement in 16 its surface view after acid-washing stainless steel and be shown in Fig. 7 (a) and 7 (b), and comparative example 33 and to implement in 19 its surface view after acid-washing stainless steel and be shown in Fig. 8 (a) and 8 (b).
Table 3
(439 steel in use listed by table 3,439 steel do not comprise molybdenum (Mo), but silicon (Si) content is 0.3wt% or less.)
As can be seen from Table 3, when pickling comprises 439 steel (the comparative example 29-31 and embodiment 13-15) of 17wt% chromium, can normal pickling 439 steel under the redox potential of 550mV or higher and the free hydrogen fluoric acid (HF) of 5-12g/l.But, when such as redox potential is less than 550mV shown in comparative example 29, can finds out and there occurs underpickling, when such as the concentration of free hydrogen fluoric acid is greater than 12g/l shown in comparative example 31, can finds out and there occurs over-pickling.The redox potential of 550mV or higher means that the concentration of the hydrogen peroxide remained in pickling is maintained predeterminated level by needs, and when hydrogen peroxide remains in mixed acid solution, normally can measure the redox potential of 550-600mV.
Simultaneously, even if also can find out when ladle contains the chromium of 17wt%, there is 430J1L steel and the 436L steel of steel grade component, wherein Si content more than 0.3wt% and Mo content more than 0.5wt%, free hydrogen fluoric acid (HF) pickling of available 20-30g/l, but when use comprises the mixed acid solution of low concentration hydrofluoric acid, can underpickling be there is.In this case, when the redox potential of mixed acid solution is 320mV or higher, pickling can be carried out.As Fe in metal ion in mixed acid solution
3+ion and Fe
2+ratio (the Fe of ion
3+/ Fe
2+) when being 1 or larger, can pickling be carried out, but generally for the redox potential maintaining 320mV or higher, need the hydrogen peroxide of predetermined amount to be injected into continuously in mixed acid solution.
Fig. 6 (a) and 6 (b) to illustrate in comparative example 29 and comparative example 31 its surface view after acid-washing stainless steel respectively.Fig. 6 (a) illustrates, when the free hydrofluoric acid concentration of mixed acid solution in comparative example 29 and redox potential low time, stainless steel surface generation underpickling.Fig. 6 (b) illustrates in comparative example 31, when the concentration of the free hydrogen fluoric acid applied exceedes concentration range of the present invention, over-pickling occurs, and therefore occurs by dissolving the surface roughening caused.
In addition, Fig. 7 (a) and 7 (b) to respectively illustrate in comparative example 32 and embodiment 16 its surface view after acid-washing stainless steel.Fig. 7 (a) illustrates, in comparative example 32, due to the free hydrogen fluoric acid of lower concentration, and stainless steel surface generation underpickling.Fig. 7 (b) describes the shape on the surface of the normal pickling according to embodiment 16.
In addition, Fig. 8 (a) and 8 (b) to respectively illustrate in comparative example 33 and embodiment 19 its surface view after acid-washing stainless steel.Fig. 8 (a) illustrates, in comparative example 33, due to the free hydrogen fluoric acid of lower concentration, and stainless steel surface generation underpickling.Fig. 8 (b) describes the shape on the surface of the normal pickling according to embodiment 19.
By above-described embodiment, can find out, according to institute's containing element in steel, there are differences between the pickling feature of the steel of each steel grade, this have impact on concentration and the redox potential of free hydrofluoric acid in the mixed acid solution that can be used for carrying out pickling.
Although more than show and describe exemplary, do not departing from the scope of the invention situation be defined by the appended claims, the modifications and variations that can make will be apparent for a person skilled in the art.
Claims (15)
1. a method for pickling high chromium content ferrite cold rolled stainless steel sheet, the method comprises:
Electrolytic pickling operates, and uses neutral salt and sulfuric acid to being equal to or greater than 1030 DEG C and the high chromium content ferrite cold rolled stainless steel sheet comprising 17-26wt% chromium of annealing under being equal to or less than the annealing temperature of 1050 DEG C carries out electrolytic pickling; And
Mixing acidleach operation, immerses the high chromium content ferrite cold rolled stainless steel sheet of electrolytic pickling and comprises in the mixed acid solution of sulfuric acid and hydrofluoric acid;
Wherein, in electrolytic pickling operation, the summation of the amount of the electric current applied in the amount of the electric current applied in neutral salt electrolysis acid cleaning process and sulphuric acid electrolyte acid cleaning process is controlled as being equal to or greater than 12A/dm
2and be equal to or less than 20A/dm
2.
2. a method for pickling high chromium content ferrite cold rolled stainless steel sheet, the method comprises:
Electrolytic pickling operates, and uses neutral salt and sulfuric acid to being equal to or greater than 930 DEG C and the high chromium content ferrite cold rolled stainless steel sheet comprising 17-26wt% chromium of annealing under being less than the annealing temperature of 1030 DEG C carries out electrolytic pickling; And
Mixing acidleach operation, immerses the high chromium content ferrite cold rolled stainless steel sheet of electrolytic pickling and comprises in the mixed acid solution of sulfuric acid and hydrofluoric acid;
Wherein, in electrolytic pickling operation, the summation of the amount of the electric current applied in the amount of the electric current applied in neutral salt electrolysis acid cleaning process and sulphuric acid electrolyte acid cleaning process is controlled as being equal to or greater than 30A/dm
2and be equal to or less than 50A/dm
2.
3. the method for pickling high chromium content ferrite cold rolled stainless steel sheet according to claim 1 and 2, wherein, the amount of the electric current applied in described neutral salt electrolysis acid cleaning process is equal to or greater than 8A/dm
2, the amount of the electric current applied in described sulphuric acid electrolyte acid cleaning process equals 0 or be equal to or greater than 8A/dm
2.
4. the method for pickling high chromium content ferrite cold rolled stainless steel sheet according to claim 1 and 2, wherein, based on the gross weight of described high chromium content ferrite cold rolled stainless steel sheet, when silicon (Si) content is equal to or less than 0.3wt% or molybdenum (Mo) content is equal to or less than 0.5wt%, described mixed acid solution comprises the sulfuric acid of 80-150g/l and the free hydrogen fluoric acid of 5-12g/l, and its redox potential (ORP) is equal to, or greater than 550mV.
5. the method for pickling high chromium content ferrite cold rolled stainless steel sheet according to claim 4, wherein, joins hydrogen peroxide in described mixed acid solution, is equal to or greater than the level of 550mV to make the redox potential of described mixed acid solution maintain.
6. the method for pickling high chromium content ferrite cold rolled stainless steel sheet according to claim 1 and 2, wherein, based on the gross weight of described high chromium content ferrite cold rolled stainless steel sheet, when silicon (Si) content is greater than 0.3wt% or molybdenum (Mo) content is greater than 0.5wt%, described mixing acidleach operation allows described mixed acid solution to comprise the sulfuric acid of 80-150g/l and the free hydrogen fluoric acid of 20-30g/l, and its redox potential is equal to or greater than 320mV.
7. the method for pickling high chromium content ferrite cold rolled stainless steel sheet according to claim 6, wherein, joins hydrogen peroxide in described mixed acid solution, is equal to or greater than the level of 320mV to make the redox potential of described mixed acid solution maintain.
8. the method for pickling high chromium content ferrite cold rolled stainless steel sheet according to claim 1 and 2, wherein, uses the electrolytic solution comprising 100-250g/l sodium sulfate to carry out described neutral salt electrolysis pickling.
9. the method for pickling high chromium content ferrite cold rolled stainless steel sheet according to claim 8, wherein, the temperature range of the electrolytic solution used in described neutral salt electrolysis pickling is 50 DEG C-90 DEG C.
10. the method for pickling high chromium content ferrite cold rolled stainless steel sheet according to claim 1 and 2, wherein, 24-100 second is carried out in described neutral salt electrolysis pickling.
The method of 11. pickling high chromium content ferrite cold rolled stainless steel sheets according to claim 1 and 2, wherein, use the electrolytic solution of the sulfuric acid or metal sulfate comprising 50-150g/l to carry out described sulphuric acid electrolyte pickling, wherein said metal sulfate is by being formed at least one dissolving metal in chosen from Fe, chromium, nickel, copper, manganese and titanium in the sulfuric acid of 50-150g/l.
The method of 12. pickling high chromium content ferrite cold rolled stainless steel sheets according to claim 11, wherein, the temperature range of the electrolytic solution used in described sulphuric acid electrolyte pickling is 30 DEG C-60 DEG C.
The method of 13. pickling high chromium content ferrite cold rolled stainless steel sheets according to claim 1 and 2, wherein, 10-50 second is carried out in described sulphuric acid electrolyte pickling.
The method of 14. pickling high chromium content ferrite cold rolled stainless steel sheets according to claim 1 and 2, wherein, 25-90 second is carried out in described mixing acidleach operation.
The method of 15. pickling high chromium content ferrite cold rolled stainless steel sheets according to claim 1 and 2, wherein, when carrying out described mixing acidleach operation, maintains-0.2V to 0V by the open circuit potential of described high chromium content ferrite cold rolled stainless steel sheet.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020130091116A KR101461815B1 (en) | 2013-07-31 | 2013-07-31 | High Speed Pickling Method for Surface Improvement of High Chromium Ferritic Stainless Cold Steel Strip |
| KR10-2013-0091116 | 2013-07-31 | ||
| PCT/KR2014/006812 WO2015016538A1 (en) | 2013-07-31 | 2014-07-25 | Method for pickling high-chrome ferritic stainless steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN105431574A true CN105431574A (en) | 2016-03-23 |
| CN105431574B CN105431574B (en) | 2018-04-24 |
Family
ID=52290346
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201480043240.8A Active CN105431574B (en) | 2013-07-31 | 2014-07-25 | The method of pickling high chromium content ferrite stainless steel |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP6105167B2 (en) |
| KR (1) | KR101461815B1 (en) |
| CN (1) | CN105431574B (en) |
| WO (1) | WO2015016538A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114959863A (en) * | 2022-06-14 | 2022-08-30 | 山西太钢不锈钢股份有限公司 | Surface pickling method for chromium ultrapure ferrite stainless steel with different silicon and manganese contents |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101951936B1 (en) | 2017-08-24 | 2019-02-25 | 주식회사포스코 | Method for Manufacturing High Strength Cold Steel Strip |
| KR102020512B1 (en) * | 2017-12-15 | 2019-09-10 | 주식회사 포스코 | High chromium ferritic stainless steel excellent in pickling property and its pickling method |
| KR102264958B1 (en) | 2019-11-15 | 2021-06-16 | 한국생산기술연구원 | Pretreatment Solution for Soot Reduction and Low-Temperature Vacuum Carburizing Method Using the Same |
| JP7526090B2 (en) | 2020-12-28 | 2024-07-31 | 日鉄ステンレス株式会社 | Ferritic Stainless Steel |
| CN114150124B (en) * | 2021-12-09 | 2023-04-11 | 山西太钢不锈钢股份有限公司 | Annealing and pickling process method for high-chromium-nickel stainless steel cold-rolled steel strip |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1168823A (en) * | 1996-02-27 | 1997-12-31 | 犹齐诺·萨西洛公司 | Process for pickling piece of steel and in particular sheet strip of stainless steel |
| CN1505696A (en) * | 2001-04-09 | 2004-06-16 | AK�ʲ���˾ | Hydrogen peroxide pickling scheme for stainless steel grades |
| KR20120075344A (en) * | 2010-12-28 | 2012-07-06 | 주식회사 포스코 | Environmental-friendly and high speed pickling process for ferritic stainless cold strip with good surface quality |
| KR20120075345A (en) * | 2010-12-28 | 2012-07-06 | 주식회사 포스코 | High speed pickling method for surface improvement of high chromium ferritic stainless cold steel strip |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1161500A (en) * | 1997-08-22 | 1999-03-05 | Nisshin Steel Co Ltd | Descaling of stainless steel strip and heat resistant steel strip |
| KR101056246B1 (en) * | 2004-01-13 | 2011-08-11 | 주식회사 포스코 | Manufacturing method of ferritic stainless steel sheet |
| KR100720278B1 (en) * | 2005-12-26 | 2007-05-22 | 주식회사 포스코 | A high speed descaling method for stabilized ferritic stainless steel having nb and high cr |
| KR101243021B1 (en) * | 2010-12-28 | 2013-03-12 | 주식회사 포스코 | Pickling method and pickling solution for preventing and removing defects of low-chrome ferritic stainless steel in the pickling process |
-
2013
- 2013-07-31 KR KR1020130091116A patent/KR101461815B1/en active IP Right Grant
-
2014
- 2014-07-25 CN CN201480043240.8A patent/CN105431574B/en active Active
- 2014-07-25 JP JP2016531518A patent/JP6105167B2/en active Active
- 2014-07-25 WO PCT/KR2014/006812 patent/WO2015016538A1/en active Application Filing
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1168823A (en) * | 1996-02-27 | 1997-12-31 | 犹齐诺·萨西洛公司 | Process for pickling piece of steel and in particular sheet strip of stainless steel |
| CN1505696A (en) * | 2001-04-09 | 2004-06-16 | AK�ʲ���˾ | Hydrogen peroxide pickling scheme for stainless steel grades |
| KR20120075344A (en) * | 2010-12-28 | 2012-07-06 | 주식회사 포스코 | Environmental-friendly and high speed pickling process for ferritic stainless cold strip with good surface quality |
| KR20120075345A (en) * | 2010-12-28 | 2012-07-06 | 주식회사 포스코 | High speed pickling method for surface improvement of high chromium ferritic stainless cold steel strip |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114959863A (en) * | 2022-06-14 | 2022-08-30 | 山西太钢不锈钢股份有限公司 | Surface pickling method for chromium ultrapure ferrite stainless steel with different silicon and manganese contents |
Also Published As
| Publication number | Publication date |
|---|---|
| CN105431574B (en) | 2018-04-24 |
| JP2016525632A (en) | 2016-08-25 |
| KR101461815B1 (en) | 2014-11-13 |
| WO2015016538A1 (en) | 2015-02-05 |
| JP6105167B2 (en) | 2017-03-29 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5768141B2 (en) | Eco-friendly high-speed pickling process for producing low chromium ferritic stainless steel cold rolled steel sheets with excellent surface quality | |
| CN105431574A (en) | Method for pickling high-chrome ferritic stainless steel | |
| KR101228730B1 (en) | High Speed Pickling Method for Surface Improvement of High Chromium Ferritic Stainless Cold Steel Strip | |
| CA2849304C (en) | Stainless steel pickling in an oxidizing, electrolytic acid bath | |
| JP6031606B2 (en) | High speed pickling process for producing austenitic stainless cold rolled steel sheet | |
| CN108359999A (en) | A kind of brass wire environmental protection pickle and its methods for making and using same | |
| KR101243021B1 (en) | Pickling method and pickling solution for preventing and removing defects of low-chrome ferritic stainless steel in the pickling process | |
| KR101359098B1 (en) | High speed pickling process for austenitic stainless cold strip | |
| EP0960221B1 (en) | Method for pickling products of a metal alloy containing iron and of titanium and alloys thereof | |
| JPH0357196B2 (en) | ||
| KR101382934B1 (en) | High Speed Pickling Process for Improving Corrosion Resistance of Austenitic Stainless Cold Strip | |
| KR101528052B1 (en) | The Method for Pickling High Cromium Ferrite Stainless Cold Steel Strip using Mixed Acid | |
| Azzerri et al. | Potentiostatic pickling: a new technique for improving stainless steel processing | |
| KR101353856B1 (en) | High speed pickling process at low temperature for austenitic stainless cold strip | |
| JP2000511594A (en) | Method for pickling alloy products in the absence of nitric acid, method for recovering waste liquid from pickling, and apparatus therefor | |
| KR101145601B1 (en) | A descaling method for austenite stainless steel | |
| KR100368207B1 (en) | Electrolytic pickling solution for cold annealed austenitic stainless steel sheet | |
| JP2002348700A (en) | DESCALING METHOD FOR COLD-ROLLED AND ANNEALED Cr-BASED STAINLESS STEEL SHEET | |
| WO2002086199A2 (en) | Continuous electrolytic descaling of stainless steel | |
| JPH03107498A (en) | Method for dissolving steel at high speed by cathodic electrolysis |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CP03 | Change of name, title or address |
Address after: Seoul, South Kerean Patentee after: POSCO Holdings Co.,Ltd. Address before: Gyeongbuk, South Korea Patentee before: POSCO |
|
| CP03 | Change of name, title or address | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20230512 Address after: Gyeongbuk, South Korea Patentee after: POSCO Co.,Ltd. Address before: Seoul, South Kerean Patentee before: POSCO Holdings Co.,Ltd. |
|
| TR01 | Transfer of patent right |