CN1231615C - Continuous electrolytic pickling and descaling of carbon steel and stainless steel - Google Patents
Continuous electrolytic pickling and descaling of carbon steel and stainless steel Download PDFInfo
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- CN1231615C CN1231615C CNB018220649A CN01822064A CN1231615C CN 1231615 C CN1231615 C CN 1231615C CN B018220649 A CNB018220649 A CN B018220649A CN 01822064 A CN01822064 A CN 01822064A CN 1231615 C CN1231615 C CN 1231615C
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- 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
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- C25F1/04—Pickling; Descaling in solution
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Abstract
Continuos electrolytic method in a neutral solution for the pickling and the descaling of carbon steels and stainless steels, in the presence of electrolysis current flow indirect effects, said current being AC or DC and having a frequency lower than 3 Hz, characterized in that the anodic treatment times and the cell currents are selected according to the formula: It=c+kI where: I is the current density crossing the cell; t is the anodic treatment time; c is the constant fraction of electric charge density outputted for the direct oxide change anodic reactions; and k is a time constant for the calculation of the fraction of electric charge density, proportional to the current density I (kI), outputted for the indirect anodic reactions linked to Oxygen development and to the consequent acidification at the steel/electrolytic solution interface (Carbon steels) or at the scale/electrolytic solution interface (stainless steels).
Description
Invention is described
The present invention relates to the continuous pickling neutral solution (pH scope from 6.0 to 8.0), the hot-rolled carbon steel band carried out by electrolytic method.The invention further relates to the continuous de-scaling field of stainless strip, de-scaling is in order to remove because of thermal treatment, comprises the influence of hot rolling and annealed, and the oxide on surface that forms.
With respect to the traditional method of carrying out in acid tank, the method for this neutrality electrolytic pickling and de-scaling has following advantage basically: adopting does not have danger, does not have harm and free of contamination pickling tank; Residue is handled easily and is reclaimed; Great surface quality after the material pickling.
As known to, in solution, can systematically represent with following formula in the main anodic reaction that the oxidized surface of hot-rolled carbon steel takes place in theory:
First reaction (0) only takes place under low electrode potential, and is unessential as pickling reaction; When current density value (I) surpasses predetermined threshold value (I
0) time, this reaction in fact is negligible.
So, as I＞I
0The time, what take place on the steel surface that oxide covers is second reaction (1) and the 3rd reaction (2).Reaction (1) makes the interface acidifying of metal-oxide skin, and reaction (2) immediately becomes oxide skin into soluble compounds because of the existence at acid interface.Therefore, these two reactions (1) and (2) have constituted the fundamental mechanism of electrolytic pickling in the neutral solution.
Be close to when dissolving fully at surface scale, the anodic oxidation that following metal takes place by the 4th reaction (3) begins to increase, up to the balancing speed that reaches by all from surface removing (cleanup acid treatment end) time when oxide skin under the passive state.So under the electrolytic pickling mechanism that is limited by second reaction (1) and the 3rd reaction (2), the 4th reaction (3) is unessential.
Certainly, for forming circuit, used suitable supporting electrode (being counter electrode again), the cathodic reaction on it can make stock solution generation charge neutrality.
In this neutral solution electrolytic pickling method, above-mentioned anodic reaction takes place under diffusion control.This means that speed of reaction depends on reactant and the diffusion of thing by interfacial layer (stream) produced in reaction, this further depends on the lip-deep hydrokinetics of steel.Significantly, the increase meeting of solution whirlpool brings reverse effect to the speed that corrodes oxide skin at the interface, because it equally also can increase the hydrogen ion (H that causes interface acidifying [reaction (1)]
+) flow.
And, by both being suitable for anode dissolution, the electrolysis Faraday's law that also is suitable for the cathodic deposition method as can be known, (variation) amount of substance that obtains on electrode becomes positive example with the amount of electric charge by electrolytic circuit.More specifically, the amount that obtain the needed electric charge of (change) a certain amount of material is a constant: for example, for arbitrary material of monovalent, need 1 farad, i.e. 96500 coulombs electric charge.The above-mentioned equation that is expressed as:
Q=I
Tot* t=constant
Here, Q be electric charge amount (with the coulomb is unit, C), I
TotBe that (with the ampere is unit to used electric current, and A), t is that (with the second is current potential to electrolysis time, s).
This equation is applicable to optional I
TotPerhaps therefore t, for corresponding electrolysis time, uses several different current value I
Tot, can obtain identical effect.
As known to because chromium extremely sensitive to oxidation is rich in chromic oxide in the stainless surface scale after the thermal treatment significantly, this is difficult to remove in the follow-up cleanup acid treatment of carrying out in acidic solution.
Usually, because ecological, that adopt in stainless pickling is the mixture of strong inorganic acid, i.e. HNO
3/ HF solution or recently introduced H
2SO
4/ HF/H
2O
2Solution.
Yet, before carrying out chemical pickling, in stainless steel is made,, adopted the de-scaling pre-treatment in order to accelerate the operation of whole removing surface scale.The effect of this step de-scaling is oxide skin is carried out the removing of modification to promote that it is follow-up.The oxide skin treatment process of hot rolling stainless steel strip mainly is to use melting salt washing trough (thermochemistry de-scaling) or electrolysis treatment.
A kind of thermochemical method that is used for de-scaling at present is to flood in the washing trough of oxidisability melting salt, chromic oxide (the perhaps mixed oxide of chromium/iron) can be transformed into soluble chromic compound.
The electrolysis de-scaling is a kind of common commercial run, can carry out in acidic electrolyte bath, also can carry out in neutral electrolyte, and negatively charged ion is sulfate ion normally.Attractive especially is the electrolysis descaling method that carries out in neutral solution.In fact, such de-scaling can make oxide skin dissolution effectively and can the oxide skin of removing directly be separated with solution by precipitation, and need not the processing (as by neutralization) of resistates.In addition, the structure of this equipment does not need special corrosion-resistant material.
In neutral solution, cause the oxide skin of electrolysis de-scaling change main anodic reaction can be systematically with as shown in the formula subrepresentation:
In order to constitute electrolytic circuit, used supporting electrode (perhaps counter electrode), the cathodic reaction on it can make stock solution generation charge neutrality.
Above-mentioned two anodic reactions produce acidifying at oxide skin/solution interface place.Described acidifying has determined oxide skin further dissolving according to following reaction:
(
) (7)
Certainly, reaction (7) only occurs over just on the austenitic stainless steel, owing to do not contain the nickel as alloyed metal of appropriate amount in ferritic stainless steel.
The dissolved side effect of iron and nickel oxide is a large amount of Cr
2O
3Anode can take place to be changed.
So the mechanism of final neutral solution electrolysis de-scaling comprises the anodic oxidation and the interface acidifying of chromium, if this has determined the dissolving of the nickel oxide of ferric oxide and existence.
Be close to when dissolving fully at surface scale, the anodic oxidation of lower metal begins to increase, up to the balancing speed that reaches according to reaction as follows under the passive state:
Here, Me represents the Fe-Cr-Ni alloy; Then, just only react (1) and (5), yet the latter has slow many speed with respect to the former.
In neutral solution pickling descaling method, all above-mentioned being reflected under the diffusion control are taken place.This means that speed of reaction depends on reactant and the diffusion of thing by interfacial layer produced in reaction, this further depends on the lip-deep hydrokinetics of steel.Significantly, the increase meeting of solution whirlpool produces a contrary effect to the speed that corrodes oxide skin at the interface, because it also can increase the hydrogen ion (H that causes interface acidifying [reaction (1)]
+) flow.
And, by being suitable for anode dissolution, the electrolysis Faraday's law that also is suitable for the cathodic deposition method as can be known, (variation) amount of substance that obtains on electrode is proportional with the amount of electric charge by electrolytic circuit.More specifically, it is a constant (for example,, needing 1 farad, promptly 96500 coulombs) for the amount that will obtain the needed electric charge of (change) a certain amount of material for arbitrary material of monovalent.Therefore, for the electrolysis transformation of quantitative material, corresponding current density is a constant.
Q=I
Tot* t=constant
Here, Q be electric charge amount (with the coulomb is unit, C), I
TotBe that (with the ampere is unit to used electric current, and A), t is that (with the second is current potential to electrolysis time, s).This equation is applicable to optional I
TotPerhaps therefore t, for corresponding electrolysis time, uses several different current value I
Tot, can obtain identical effect.
Have now found that for the method for neutral solution electrolytic pickling or de-scaling, above-mentioned classical electrolysis equation may be derived wrong result.In fact, for quantitative surface scale (supposition oxide skin The Nomenclature Composition and Structure of Complexes is a constant) and definite technique initialization, can see that in order to obtain gratifying pickling or de-scaling, i.e. the transformation fully of oxide skin is for 1dm
2Oxidized steel surface, use the 15A at least (carbon steel) that continues 40s, continue the anodizing of the 10A at least (stainless steel) of 10s.Now, if wish (60A/dm for example with another current density value I
2With the quickening process) handle (pickling/de-scaling) this identical materials, the new treatment time can not calculate with classical electrolyzing, because the current density of operation is too high, the end value of gained will prove too short so that can not method of assuring be effective.
So the information of deriving according to classical electrolysis equation is not suitable for being used for calculating the amount that is applied to the electric charge on the electrolyzer in the neutral electrolysis process.
Therefore, in this special field, when having the electric current indirect effect, requiring, the method that can provide antianode treatment time and electrolytic cell currents correctly to select is provided, and can calculate the size of corresponding de-scaling service line and equipment.
The present invention has satisfied this requirement, and other the advantage that will express in the back further is provided.
In fact, the objective of the invention is when having the Faradaic current indirect effect continuous electrolysis method of in neutral solution, carbon steel and stainless steel being carried out pickling and de-scaling.Described electric current is the AC electric current that DC electric current or frequency are lower than 3Hz, it is characterized in that anodizing time and electrolytic cell currents select according to following formula:
It＝c+kI
Here:
-I strides electrolytic cell currents density;
-t is the anodizing time;
-c is the electric density constant component that changes anodic reaction output for the direct oxidation thing; And
-k is used for calculating and current density I proportional (kI), the time constant of the electric density part of exporting for indirect anodic reaction, this indirect anodic reaction and oxygen develop (oxygendevelopment) and thereupon at the steel/electrolyte solution interface of carbon steel, the acidifying that stainless oxide skin/solution interface place takes place links.
Preferred neutral salt solution is that 0.5 to 2.5M sodium sulfate is formed by concentration, and temperature range is at 30 to 100 ℃.
Especially, with the DC electrolysis time, find, when the minimum of electric charge c 200 to 1250C/dm
2(carbon steel) and 40 to 200C/dm
2In the scope of (stainless steel), and time constant k at 2s to the scope of 25s, preferably, be 2 to 11s to carbon steel, be 2 to 25s the time to stainless steel, obtained gratifying result.
To carbon steel, the treatment time is 7 to the scope of 50s, and to stainless steel, the treatment time is in 2 to 45s scope.Current density range is 10 to 80A/dm
2(carbon steel) and 5 to 150A/dm
2(stainless steel).
According to the theoretic consideration of here not announcing, foundation unpredictable results of the present invention can pass through to consider the mechanism and the inhomogeneity thereof of electrolytic pickling, and the not same-action of electric current in each electrolytic pickling reaction makes an explanation.Like this, the increase of just finding the electrochemical conversion speed of reaction is lowly more next than the increase that is directly proportional with total electrolytic cell currents.
The actual result that this is true, as mentioning to this, electrolysis process in this neutral solution can not be controlled according to the homoeostasis of the amount of the electric charge of being exported, and this does not normally contain the situation (surface therefore and acidifying) of electric current indirect effect in electrolysis process.The selection of anodizing time and electrolytic cell currents should consider that the amount of electric charge also will increase when used electric current increases.
In the relevant pickling line of design, also the condition of the neutral electrolysis process of control should be observed, the effect of this method under the different in flow rate of handled band should be guaranteed.
The anodizing time-dependent in the speed of service line (v) and make the electrode total length (L) of handled band generation anodic polarization.So the equation of the previously described quantity of electric charge in neutral solution electrolysis process output can be rewritten as following form:
I＝c/(L/v-k)
Therefore, another object of the present invention is the use of above-mentioned electrolysis process, it is characterized in that, by setting the width and the flow velocity of band, total anode electrode length, and and then set the length of relevant continuous neutral electrolysis treatment service line, determine the outward current of selecting according to aforesaid method.
The electrolysis treatment of steel band is carried out in the electrolyzer of being made up of a series of electrodes that link with the power supply antipole usually, determines alternatively in the anode of wanting to carry out on the de-scaling band or the order of cathodic polarization.Although descaling process only needs anodic polarization, the advantage that the adding of cathode portion brings is that electrochemical reaction occurs directly on the band, and band needn't directly link with power supply; Like this, just can avoid using expensive conductive rollers.So, on band, apply the single length (L of the electrode length overall (L) of anodic polarization by each electrode unit
a) summation provide.
According to the convenient criteria of equipment, groove can vertical expansion also can horizontal development.
In addition, disclosed in the present invention neutral electrolysis treatment equation shows, has one to handling sluggish electrolysis time (k).This means equipment design, should consider that total anodizing time (t) is bigger than k in the neutral solution electrolysis treatment that is used for steel band
t＝L/v＞k
In the practice, the electrolysis descaling method carries out with the order branch of anode and cathodic current pulse:
L＝n*L
a
(L here
aBe the length of each anode current impulse, n is the number of impulse of current), the frequency of each anode current impulse (f) should be
f＝v/L
a＜*n/k
Here, coefficient introduces (therefore having supposed symmetric cathodic current pulse) overall treatment time for considering
For k
Min=2s and n
Max=12,
Can get f
Max＜3hz
This frequency limit value of neutral solution electrolytic pickling is compatible with treatment process advanced person's reaction mechanism, has hinted to be the interface acidifying of promotes oxidn thing dissolved electrification.For hot-rolled carbon steel band as under predetermined industrial condition, (using the rolling postcooling pattern of constant), gained oxide skin is made up of and form near constant, the required lowest charge amount c of electrolytic pickling to depend on and oxide skin is carried out broken mechanical treatment before the pickling.
The AC electric current that also can adopt frequency to be lower than 3Hz according to the electrolysis process in the neutral solution of the present invention carries out, and for suitable c ' and k ' value, determines overall treatment time and used electric current according to following formula:
It＝c’+k’Xt
Arrive this, only the present invention has been carried out concise and to the point description, after this, for making its purpose, feature, advantage and application model become obviously, by by the following examples and accompanying drawing, disclose embodiment of the present invention.
Fig. 1 is oxide skin mark P (t)/P
TAs the function of time and the de-scaling synoptic diagram that changes, the initial oxidation skin is P
T1And P
T2, and P
T2＞P
T1This figure obtains in conjunction with the de-scaling equation that draws according to the experimental observation to the mass loss in the de-scaling process.
The situation that Fig. 2 relates to is, wherein c=70C/dm
2, and shown four hyperbolic line branches, from the bottom up, k equals 1,2,3 and 4s successively, and asymptotic line I=0A/dm is arranged
2And t=ks.
Embodiment 1
A kind of common soft steel has heat scale, leads to crushing (approximately extending 2.5%) to carry out mechanical pretreatment with rolling, carries out continuous electrolytic pickling according to method of the present invention in neutral solution.For the oxide skin of this type, find c=490C/dm
2And k=3.7s.And, can take place for making the oxide skin transformation reaction, the current density I of employing should satisfy I＞I
0, should use I
0=10A/dm
2
The continuous neutral electrolytic pickling service line used to the wide band of 1.5m, work in 90m/min under the stable status, when roll starts and when stopping at 20m/min, set total anode electrode length (L) according to the electrolytic cell currents of determining according to neutral electrolytic pickling of the present invention equational regulation, and and then set the length of pickling installation.
According to the equation of being considered, the function of being applied to of listing in the 3rd row in table 1 length (L) that current density (I) on the electrolytic pickling groove is an anode electrode and variable service line speed (V); The 4th row are electric density (Q), and the 5th row are total current (I of output
Tot), this total current is the calculated value that current density multiply by the anode electrode surface.Significantly, under steady state speed 90m/min, for the electric density (Q) of electrolytic pickling output along with anode electrode length reduce increase.Similarly, used total current (I
Tot) increase.
Table 1
| V, (m/min) service line speed | L, (m) anode length | I，(A/dm 2) I＝490/(L/v-3.7) | Q，(C/dm 2) Q＝I*t | I tot(kA) I tot＝I*S | I tot°(kA) |
| 90 | 32 | 28 | 593 | 267 | 221 |
| 90 | 28 | 33 | 611 | 275 | 221 |
| 90 | 24 | 40 | 637 | 287 | 221 |
| 90 | 20 | 51 | 678 | 305 | 221 |
| 90 | 16 | 70 | 750 | 338 | 221 |
| 20 | 16 | 11 | 531 | 53 | 49 |
| 20 | 8 | 24 | 579 | 58 | 49 |
Electric current I in the 6th row
Tot° be the (I that calculates according to classical electrolysis law
Tot°=I ° * S=490*v/L*S).Significantly, do not consider the method among the present invention, when service line speed was identical, along with reducing of device length, the size of supply current was for guaranteeing that complete pickling will be obviously insufficient.
And, from table 1, can know by inference, the operation of lower velocity (20m/min) means that used total anode electrode length can not surpass 16m, in order to avoid the I＞I that can not satisfy condition
0This can use the part of electrode and power supply to obtain by segmentation, no matter and the anodic total length of in electrolyzer, being adorned how.
Embodiment 2
A kind of silicon steel (3%Si) that is used for magnetic applications has heat scale, by shot-peening mechanical pretreatment on the line, carries out continuous neutral electrolytic pickling according to method of the present invention.Because shotblasting machine has been removed a part of oxide skin, the removing fully and the service line speed of oxide skin are inversely proportional to, thus find for this material, when v=20m/min, c
1=525C/dm
2, when v=40m/min, c
2=680C/dm
2, under two kinds of situations k=3.1s is arranged all, and, the density I of used electric current＞15A/dm can take place for making the oxide skin transformation reaction
2
The continuous neutral electrolytic pickling service line used to the wide band of 1.2m, work in 40 and 60m/min, set total anode electrode length (L) according to the electrolytic cell currents of determining according to continuous neutral electrolytic pickling of the present invention equational regulation, and and then set the length of pickling installation.
According to the equation considered, the current density of listing in table 2 (I) on the electrolytic pickling groove of being applied to is that (function v), all other amounts of being correlated with are also listed in table for the length (L) of anode electrode and variable service line speed.
Table 2
| V, (m/min) service line speed | L, (m) anode length | I，(A/dm 2) I＝c/(L/v-3.1) | Q，(C/dm 2) Q＝I*t | I tot(kA) I tot＝I*S | I tot°(kA) |
| 20 | 12 | 16 | 574 | 46 | 42 |
| 20 | 10 | 20 | 586 | 47 | 42 |
| 20 | 8 | 25 | 603 | 48 | 42 |
| 20 | 6 | 35 | 634 | 51 | 42 |
| 20 | 4 | 59 | 708 | 57 | 42 |
| 40 | 24 | 21 | 744 | 119 | 109 |
| 40 | 20 | 25 | 758 | 121 | 109 |
| 40 | 16 | 33 | 781 | 125 | 109 |
| 40 | 14 | 38 | 798 | 128 | 109 |
| 40 | 12 | 46 | 821 | 131 | 109 |
| 40 | 10 | 57 | 857 | 137 | 109 |
| 40 | 8 | 76 | 917 | 147 | 109 |
Like this, just confirmed, when speed equates, when anode electrode length reduces, be electric density (Q) increase of electrolytic pickling output.Similarly, used total current (I
Tot) increase.When speed was 20m/min, actual anode length should be no more than 12m, in order to avoid the too low (I＜I of current density
0).Can know by inference thus, the pickling installation of being considered that is used for this material can be determined yardstick that in anode electrode length be between the 10-14m easily.
Yet, equally in the case, design electrolytic pickling equipment according to classical electrolysis law and will cause underestimating power supply.
Embodiment 3
To be applied to (c=490C/dm in the de-scaling of the pretreated ordinary hot steel rolling of the mechanical descaling among the embodiment 1 according to method of the present invention
2, k=3.7s and I
0=10A/dm
2).
(but the operating speed of the pickling line of strip width=1.5m) is in 60 to 120m/min scope for the total anode electrode length L=24m that contains.
The current density of listing in table 3 (I) that is applied on the electrolytic pickling groove is the length (L) and the service line speed (function v) of anode electrode.All other correlative is also listed in table 3.
Table 3
| V, (m/min) service line speed | L, (m) anode length | I，(A/dm 2) I＝490/(L/v-2.1) | Q，(C/dm 2) Q＝I*t | I tot(kA) I tot＝I*S | I tot°(kA) |
| 60 | 24 | 24 | 579 | 174 | 147 |
| 70 | 24 | 29 | 597 | 209 | 172 |
| 80 | 24 | 34 | 617 | 247 | 196 |
| 90 | 24 | 40 | 637 | 287 | 221 |
| 100 | 24 | 46 | 659 | 330 | 245 |
| 110 | 24 | 52 | 683 | 376 | 270 |
| 120 | 24 | 59 | 706 | 425 | 294 |
Significantly, do not consider disclosure invention, along with the increase of service line speed, the size of supply current is for guaranteeing that complete pickling will be obviously insufficient.
Embodiment 4
To be applied to (c=490C/dm in the pretreated ordinary hot steel rolling of the mechanical descaling among the embodiment 1 according to method of the present invention
2, k=3.7s and I
0=10A/dm
2).
De-scaling equipment is made of 12 grooves, the single anode length L of each groove
a=2m, length overall L=24m (strip width=1.5m) like this; This equipment should be able to be operated in 40 to 120m/min velocity range, according to two kinds of different technology controlling and process logics: the logic that (sees Table 4a) in one case, the power of used single power supply uses maximization (promptly, the number of the groove that uses is directly proportional with service line speed), under the another kind of situation (seeing Table 4b), all grooves of employing are constant (promptly using the current density that is directly proportional with service line speed).List among gained result table 4a below and the table 4b.
Table 4a
| V, (m/min) service line speed | Groove is counted n | I，(A/dm 2) [I＝490/(L/v-3)] | Q，(C/dm 2) [Q＝I*t] | I tot(kA) [I tot＝I*S] | I tot°(kA) |
| 40 | 4 | 59 | 708 | 142 | 98 |
| 60 | 6 | 59 | 708 | 213 | 147 |
| 80 | 8 | 59 | 708 | 283 | 196 |
| 100 | 10 | 59 | 708 | 354 | 245 |
| 120 | 12 | 59 | 708 | 425 | 294 |
Table 4b
| V, (m/min) service line speed | Groove is counted n | I，(A/dm 2) [I＝490/(L/v-3)] | Q，(C/dm 2) [Q＝I*t] | I tot(kA) [I tot＝I*S] | I tot°(kA) |
| 40 | 12 | 15 | 546 | 109 | 98 |
| 60 | 12 | 24 | 579 | 174 | 147 |
| 80 | 12 | 34 | 617 | 247 | 196 |
| 100 | 12 | 46 | 659 | 330 | 245 |
| 120 | 12 | 59 | 708 | 425 | 294 |
Show that according to the equation of continuous neutral electrolytic pickling of the present invention these two kinds of technology controlling and process logics are non-equivalences, because, reduced required total pickling electric current generally when operating in maximized used groove number following time.
Difference between these two kinds of steering logics can not be understood from the electrolyzing of classics, and needs can be underestimated the pickling electric current.
Embodiment 5
To cold rolled stain less steel, a neutral electrolysis de-scaling equipment is inserted in a pickling-annealed combination service line, operate used total anode electrode length L=4m and strip width=1.25m, be the conforming needs of thermal cycling of the stainless strip that satisfies different thickness, the processing speed that can adopt changes in 20 to 70m/min scope.
Shown in the de-scaling equation, in the 2nd row of table 5, listed and (used the direct current density (I) of electrolytic pickling groove v) down, in different service line speed; That list in the 3rd row is electric density (Q), and in the 4th row is the total current (I that will export
Tot), total current is current density to be multiply by electrode surface calculate:
Table 5
| Service line speed v, (m/min) | I，(A/dm 2) I＝70/(L/v-3) | Q，(C/dm 2) Q＝I*t | I tot(kA) I tot＝I*S | I tot°(kA) |
| 20 | 8 | 93 | 8 | 6 |
| 30 | 14 | 112 | 14 | 8 |
| 40 | 23 | 140 | 24 | 12 |
| 50 | 39 | 187 | 38 | 14 |
| 60 | 70 | 280 | 70 | 18 |
| 70 | 163 | 560 | 164 | 20 |
In the 5th row, electric current I
Tot° provide (I by the classical law of electrolysis
Tot°=I ° * S=70*v/L*S).Significantly, do not consider that along with the increase of service line speed, the size of supply current is for guaranteeing that complete pickling will be obviously insufficient according to discovery of the present invention.
Embodiment 6
A neutral electrolysis de-scaling equipment, operate in embodiment 5 in identical velocity range (20-70m/min), use bigger total electrode length, L=5.12m (strip width=1.25m).The operating parameters of this equipment that foundation de-scaling equation of the present invention calculates is listed in table 6.
Compare with the situation among the embodiment 5, according to electrolysis law, when service line speed increases, total current I
Tot° will keep identical with situation in the example 5.In fact, with respect to precedent, under the situation that speed equates, the electric current required according to de-scaling equation of the present invention reduces.
Table 6
| Service line speed v, (m/min) | I，(A/dm 2) I＝70/(L/v-3) | Q，(C/dm 2) Q＝I*t | I tot(kA) I tot＝I*S | I tot°(kA) |
| 20 | 6 | 88 | 8 | 6 |
| 30 | 10 | 99 | 12 | 8 |
| 40 | 15 | 115 | 20 | 12 |
| 50 | 22 | 137 | 28 | 14 |
| 60 | 33 | 169 | 42 | 18 |
| 70 | 50 | 221 | 64 | 20 |
Yet, also be in this case, the design of carrying out according to known electrolysis law will cause underestimating power supply.
Embodiment 7
A neutral electrolysis de-scaling equipment, total anode electrode length equals L=8m (strip width=1.25m), available processes speed is in 60 to 120m/min scope during work.List in table 7 according to this apparatus operating parameters that de-scaling equation of the present invention calculates.
Table 7
| Service line speed v, (m/min) | I，(A/dm 2) I＝70/(L/v-3) | Q，(C/dm 2) Q＝I*t | I tot(kA) I tot＝I*S | I tot°(kA) |
| 60 | 14 | 112 | 28 | 18 |
| 70 | 18 | 124 | 36 | 20 |
| 80 | 23 | 140 | 46 | 24 |
| 90 | 30 | 160 | 60 | 26 |
| 100 | 39 | 187 | 78 | 30 |
| 110 | 51 | 224 | 102 | 32 |
| 120 | 70 | 280 | 140 | 36 |
This example also proves, for other operation task linear velocity, is obviously to be wrong according to the big young pathbreaker of the supply current of the classical law of electrolysis.
Embodiment 8
Neutral electrolysis de-scaling equipment is made of the anode electrode length L of each groove 4 grooves
a=2m, and length overall L=8m (strip width=1.25m).
In embodiment 7, observed the function that distribution of current is a service line speed.Now, suppose this equipment can in addition only operate (as because operation, fault etc.) under the situation of 3 grooves, L=6m thus, used de-scaling electric current is listed in table 8.
Table 8
| Service line speed v, (m/min) | I，(A/dm 2) I＝70/(L/v-3) | Q，(C/dm 2) Q＝I*t | I tot(kA) I tot＝I*S | I tot°(kA) |
| 50 | 17 | 120 | 26 | 14 |
| 60 | 23 | 140 | 36 | 18 |
| 70 | 33 | 168 | 50 | 20 |
| 80 | 47 | 210 | 70 | 24 |
| 90 | 70 | 280 | 106 | 26 |
| 100 | 117 | 420 | 176 | 30 |
During with 3 groove operations, along with the increase of speed, caused the extra demand of total current, this fact is inscrutable according to the classical law of electrolysis institute.
Embodiment 9
Neutral electrolysis de-scaling equipment is made up of n=6 groove, and single anodic length is L
a=1m, and length overall L=6m (strip width=1.25m); (see Table 9a) in one case, the technology controlling and process logic is that the power of each power supply uses maximization (promptly, use the groove number that is directly proportional with service line speed), (seeing Table 9b) is that all grooves that adopt are constant (that is, using the current density that is directly proportional with service line speed) under the another kind of situation.
Table 9a
| Service line speed v, (m/min) | Groove is counted n | I，(A/dm 2) I＝70/(L/v-3) | Q，(C/dm 2) Q＝I*t | I tot(kA) I tot＝I*S | I tot°(kA) |
| 10 | 1 | 23.0 | 13.8 | 5.7 | 2.9 |
| 20 | 2 | 23.0 | 13.8 | 11.5 | 5.9 |
| 30 | 3 | 23.0 | 13.8 | 17.2 | 8.7 |
| 40 | 4 | 23.0 | 13.8 | 23.0 | 11.7 |
| 50 | 5 | 23.0 | 13.8 | 28.7 | 14.7 |
| 60 | 6 | 23.0 | 13.8 | 34.5 | 17.5 |
Table 9b
| Service line speed v, (m/min) | Groove is counted n | I，(A/dm 2) I＝70/(L/v-3) | Q，(C/dm 2) Q＝I*t | I tot(kA) I tot＝I*S | I tot°(kA) |
| 10 | 6 | 2.1 | 76 | 3.1 | 2.9 |
| 20 | 6 | 4.7 | 85 | 7.0 | 5.9 |
| 30 | 6 | 7.7 | 92 | 11.5 | 8.7 |
| 40 | 6 | 11.7 | 105 | 17.2 | 11.7 |
| 50 | 6 | 17.0 | 123 | 25.5 | 14.7 |
| 60 | 6 | 23.0 | 138 | 34.5 | 17.5 |
These two kinds of technology controlling and process logics are non-equivalences, because when operating in maximized groove quantity following time, reduced required total de-scaling electric current generally.Also be in this embodiment, still can underestimate the de-scaling electric current according to classical electrolysis law.
In order to satisfy further possible needs, those skilled in the art can carry out further improving and changing to method as described above, but all these drops in protection scope of the present invention defined in the attached claim.
Claims (8)
1. continuous electrolysis method in neutral solution, this method is used for carbon steel and stainless pickling and de-scaling, and there is a Faradaic current indirect effect, described electric current is AC or DC electric current, its frequency is lower than 3Hz, and anodizing time when wherein using required electrolytic cell currents and the electrolytic cell currents when adopting required treatment time are selected according to following formula:
It＝c+kI
Here:
-I strides electrolytic cell currents density;
-t is the anodizing time;
-c changes the electric density constant component that anodic reaction is exported for the direct oxidation thing;
-k is that the part (kI) of the electric density that is directly proportional with current density I is calculated and used the time constant, this electric density be for produce oxygen and on the steel/electrolyte solution interface of carbon steel or stainless oxide skin/solution interface, produce the indirect anodic reaction of acidifying thereupon and export
To each steel and each oxide skin, constant c and k are known,
For carbon steel, be the 7 anodizing times and 10 that arrive 50sec to arrive 80A/dm at scope
2Current density, the value of quantity of electric charge c from 200 to 1250C/dm
2Scope, and time constant k is from 2 to 11sec scope;
For stainless steel, be the 2 anodizing times and 5 that arrive 45sec to arrive 150A/dm at scope
2Current density, the value of quantity of electric charge c from 40 to 200C/dm
2Scope, and time constant k is from 2 to 25sec scope.
2. the continuous electrolysis method in neutral solution in the claim 1, this method is used for carbon steel and stainless pickling and de-scaling, and there is a Faradaic current indirect effect, described electric current is AC or DC electric current, its frequency is lower than 3Hz, wherein neutral solution is made up of sodium sulfate, and concentration is from 0.5 to 2.5M scope, and temperature is from 30 to 100 ℃ scope.
3. the application of one of any continuous electrolysis method in neutral solution of claim 1 to 2, this method is used for carbon steel pickling, and there is a Faradaic current indirect effect, described electric current is AC or DC electric current, frequency is lower than 3Hz, it is characterized in that, by setting width and the speed v and the electrolytic cell currents I of pickling band, according to following formula determine total anode electrode length and and then determine the length L of the continuous neutral electrolytic pickling service line of being correlated with:
I＝c/(L/v-k)
This formula is by replacing time t with ratio L/v, the rewriting of the formula in the claim 1 being obtained.
4. the application in the claim 3, wherein the technology controlling and process logic of Cai Yonging is, uses the number of the electrolyzer that is directly proportional with service line speed, and uses maximum available output.
5. the application in the claim 3, wherein the technology controlling and process logic of Cai Yonging is, the current density that constant use of all electrolyzers and use are directly proportional with service line speed.
6. the application of claim 1 or 2 the continuous electrolysis method in neutral solution, this method is used for stainless de-scaling, and there is a Faradaic current indirect effect, described electric current is AC or DC electric current, frequency is lower than 3Hz, it is characterized in that, treat the width of de-scaling band and speed v ' and electrolytic cell currents I ', determine total anode electrode length and and then determine the length L of relevant continuous electrolysis neutrality de-scaling service line according to following formula by setting ':
I’＝c’/(L’/v’-k’)
This formula is to obtain by using ratio L '/v ' to replace time t ', the formula in the claim 1 being rewritten.
7. the application in the claim 6, wherein the technology controlling and process logic of Cai Yonging is, uses the number of the electrolyzer that is directly proportional with service line speed, and uses maximum available output.
8. the application in the claim 7, wherein the technology controlling and process logic of Cai Yonging is, the current density that constant use of all electrolyzers and use are directly proportional with service line speed.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT2000RM000674 IT1316027B1 (en) | 2000-12-18 | 2000-12-18 | Continuous electrolytic method in neutral solution for pickling and descaling carbon steels and stainless steels involves selecting anodic treatment times and cell currents according to specific formula |
| ITRM2000A000674 | 2000-12-18 | ||
| IT2000RM000675 IT1316028B1 (en) | 2000-12-18 | 2000-12-18 | Continuous electrolytic method in neutral solution for pickling and descaling carbon steels and stainless steels involves selecting anodic treatment times and cell currents according to specific formula |
| ITRM2000A000675 | 2000-12-18 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1486373A CN1486373A (en) | 2004-03-31 |
| CN1231615C true CN1231615C (en) | 2005-12-14 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB018220649A Expired - Fee Related CN1231615C (en) | 2000-12-18 | 2001-12-18 | Continuous electrolytic pickling and descaling of carbon steel and stainless steel |
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| Country | Link |
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| EP (1) | EP1358367B1 (en) |
| KR (1) | KR20030076589A (en) |
| CN (1) | CN1231615C (en) |
| AT (1) | ATE276386T1 (en) |
| AU (1) | AU2002217449A1 (en) |
| DE (1) | DE60105653T2 (en) |
| ES (1) | ES2232564T3 (en) |
| WO (1) | WO2002050344A1 (en) |
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| ITRM20010223A1 (en) * | 2001-04-24 | 2002-10-24 | Ct Sviluppo Materiali Spa | METHOD FOR THE CONTINUOUS ELECTROLYTIC DESCRIPTION OF STAINLESS STEELS IN THE PRESENCE OF INDIRECT EFFECTS OF THE CURRENT PASSAGE. |
| IT1395853B1 (en) | 2009-09-30 | 2012-10-26 | Tenova Spa | SURFACE PREPARATION GROUP FOR METALLIC TAPE PRODUCTION LINES |
| ITMI20130493A1 (en) * | 2013-03-29 | 2014-09-30 | Tenova Spa | METHOD TO PROCESS THE SURFACE OF A STAINLESS STEEL LAMINATE IN A CONTINUOUS SOLFORIC ACID SOLUTION |
| CN104120438B (en) * | 2014-07-22 | 2016-04-20 | 中冶南方工程技术有限公司 | A kind of hot rolling 304 austenic stainless steel belt steel pickling production method |
| CN106181586A (en) * | 2016-07-01 | 2016-12-07 | 陕西飞机工业（集团）有限公司 | A kind of stainless steel weld joint or the anti-corrosion method in bending region |
| CN111020683A (en) * | 2019-11-22 | 2020-04-17 | 山西太钢不锈钢股份有限公司 | Automatic control method for electrolytic current of stainless steel plate with pickling |
| KR20220084392A (en) | 2019-11-25 | 2022-06-21 | 아르셀러미탈 | Electric assisted pickling of the river |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4363709A (en) * | 1981-02-27 | 1982-12-14 | Allegheny Ludlum Steel Corporation | High current density, acid-free electrolytic descaling process |
| JPH06158400A (en) * | 1992-11-24 | 1994-06-07 | Nakagawa Boshoku Kogyo Kk | Descaling method for steel product surface |
-
2001
- 2001-12-18 EP EP01271468A patent/EP1358367B1/en not_active Expired - Lifetime
- 2001-12-18 CN CNB018220649A patent/CN1231615C/en not_active Expired - Fee Related
- 2001-12-18 KR KR10-2003-7008160A patent/KR20030076589A/en not_active Application Discontinuation
- 2001-12-18 AU AU2002217449A patent/AU2002217449A1/en not_active Abandoned
- 2001-12-18 ES ES01271468T patent/ES2232564T3/en not_active Expired - Lifetime
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| DE60105653D1 (en) | 2004-10-21 |
| ATE276386T1 (en) | 2004-10-15 |
| EP1358367A1 (en) | 2003-11-05 |
| AU2002217449A1 (en) | 2002-07-01 |
| EP1358367B1 (en) | 2004-09-15 |
| DE60105653T2 (en) | 2005-09-29 |
| KR20030076589A (en) | 2003-09-26 |
| WO2002050344A1 (en) | 2002-06-27 |
| CN1486373A (en) | 2004-03-31 |
| ES2232564T3 (en) | 2005-06-01 |
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