EP2978879A1 - Method for treating in continuous the surface of a laminate made of stainless steel in a solution based on sulfuric acid - Google Patents
Method for treating in continuous the surface of a laminate made of stainless steel in a solution based on sulfuric acidInfo
- Publication number
- EP2978879A1 EP2978879A1 EP14722742.5A EP14722742A EP2978879A1 EP 2978879 A1 EP2978879 A1 EP 2978879A1 EP 14722742 A EP14722742 A EP 14722742A EP 2978879 A1 EP2978879 A1 EP 2978879A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- laminate
- comprised
- electrodes
- solution
- treatment
- 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
- 238000000034 method Methods 0.000 title claims abstract description 81
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 title claims abstract description 75
- 239000010935 stainless steel Substances 0.000 title claims abstract description 23
- 229910001220 stainless steel Inorganic materials 0.000 title claims abstract description 23
- 238000005554 pickling Methods 0.000 claims abstract description 73
- 238000011282 treatment Methods 0.000 claims abstract description 73
- 239000008151 electrolyte solution Substances 0.000 claims abstract description 18
- 238000002161 passivation Methods 0.000 claims abstract description 16
- 230000002596 correlated effect Effects 0.000 claims abstract description 8
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 49
- 239000000243 solution Substances 0.000 claims description 43
- -1 Fe3+ ions Chemical class 0.000 claims description 23
- 239000000203 mixture Substances 0.000 claims description 21
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 20
- 239000007864 aqueous solution Substances 0.000 claims description 19
- 239000000126 substance Substances 0.000 claims description 19
- 229910001447 ferric ion Inorganic materials 0.000 claims description 18
- 229910017604 nitric acid Inorganic materials 0.000 claims description 16
- 230000010287 polarization Effects 0.000 claims description 10
- 229910021645 metal ion Inorganic materials 0.000 claims description 5
- 230000015572 biosynthetic process Effects 0.000 claims description 4
- 239000011810 insulating material Substances 0.000 claims description 3
- 230000033116 oxidation-reduction process Effects 0.000 claims description 3
- 229910021607 Silver chloride Inorganic materials 0.000 claims description 2
- HKZLPVFGJNLROG-UHFFFAOYSA-M silver monochloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 claims description 2
- 230000003068 static effect Effects 0.000 claims description 2
- 229910000831 Steel Inorganic materials 0.000 description 52
- 239000010959 steel Substances 0.000 description 52
- 230000008569 process Effects 0.000 description 35
- 229910052751 metal Inorganic materials 0.000 description 19
- 239000002184 metal Substances 0.000 description 19
- 239000002253 acid Substances 0.000 description 18
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 13
- 229910001566 austenite Inorganic materials 0.000 description 12
- 150000002739 metals Chemical class 0.000 description 11
- 238000000137 annealing Methods 0.000 description 10
- 239000010410 layer Substances 0.000 description 9
- 150000007513 acids Chemical class 0.000 description 7
- 150000001875 compounds Chemical class 0.000 description 7
- 238000005406 washing Methods 0.000 description 7
- 229910052500 inorganic mineral Inorganic materials 0.000 description 6
- 229910000734 martensite Inorganic materials 0.000 description 6
- 239000011707 mineral Substances 0.000 description 6
- 238000001816 cooling Methods 0.000 description 5
- 230000007613 environmental effect Effects 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 5
- 238000003475 lamination Methods 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 4
- 229910002651 NO3 Inorganic materials 0.000 description 4
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 4
- 230000001680 brushing effect Effects 0.000 description 4
- 230000002829 reductive effect Effects 0.000 description 4
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical compound [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 description 3
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 229910044991 metal oxide Inorganic materials 0.000 description 3
- 150000004706 metal oxides Chemical class 0.000 description 3
- 230000001590 oxidative effect Effects 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- 238000005488 sandblasting Methods 0.000 description 3
- 239000002351 wastewater Substances 0.000 description 3
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000005097 cold rolling Methods 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 238000005868 electrolysis reaction Methods 0.000 description 2
- 238000005098 hot rolling Methods 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000007935 neutral effect Effects 0.000 description 2
- 230000000737 periodic effect Effects 0.000 description 2
- 239000011241 protective layer Substances 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 1
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 description 1
- 229910000754 Wrought iron Inorganic materials 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 238000002479 acid--base titration Methods 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 229910000423 chromium oxide Inorganic materials 0.000 description 1
- UOUJSJZBMCDAEU-UHFFFAOYSA-N chromium(3+);oxygen(2-) Chemical group [O-2].[O-2].[O-2].[Cr+3].[Cr+3] UOUJSJZBMCDAEU-UHFFFAOYSA-N 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000005238 degreasing Methods 0.000 description 1
- QDOXWKRWXJOMAK-UHFFFAOYSA-N dichromium trioxide Chemical compound O=[Cr]O[Cr]=O QDOXWKRWXJOMAK-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 230000003628 erosive effect Effects 0.000 description 1
- 229910001448 ferrous ion Inorganic materials 0.000 description 1
- 150000004966 inorganic peroxy acids Chemical class 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 1
- 235000013980 iron oxide Nutrition 0.000 description 1
- VBMVTYDPPZVILR-UHFFFAOYSA-N iron(2+);oxygen(2-) Chemical class [O-2].[Fe+2] VBMVTYDPPZVILR-UHFFFAOYSA-N 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 1
- 150000002823 nitrates Chemical class 0.000 description 1
- 150000004967 organic peroxy acids Chemical class 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- JRKICGRDRMAZLK-UHFFFAOYSA-L persulfate group Chemical group S(=O)(=O)([O-])OOS(=O)(=O)[O-] JRKICGRDRMAZLK-UHFFFAOYSA-L 0.000 description 1
- 235000021110 pickles Nutrition 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Inorganic materials [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 description 1
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- 235000011152 sodium sulphate Nutrition 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- 238000010301 surface-oxidation reaction Methods 0.000 description 1
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
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
- C25F7/00—Constructional parts, or assemblies thereof, of cells for electrolytic removal of material from objects; Servicing or operating
Definitions
- the method of the present invention is particularly suitable for treating a laminate made of stainless steel in order to remove the surface oxide layer (so- called "scale") which inevitably forms during the various heat treatments to which the laminate is subjected, including the hot lamination process itself.
- the pickling processes of the prior art generally provide three distinct steps.
- the first step (descaling) a chemical-physical modification of the scale is induced in order to promote detachment from the laminate.
- This step is carried out, for example, by immersing the manufactured product in baths of molten oxidizing salts, such as Kolene baths (mixtures of NaOH, NaN0 3 and NaCl) at temperatures around 500 °C ( thermochemical descaling) , or electrolytically (electrolytic descaling) in neutral or acidic aqueous solutions (for example, aqueous solutions of sodium sulfate or sulfuric acid) .
- molten oxidizing salts such as Kolene baths (mixtures of NaOH, NaN0 3 and NaCl) at temperatures around 500 °C ( thermochemical descaling)
- electrolytically electrolytic descaling
- neutral or acidic aqueous solutions for example, aqueous solutions of sodium sulfate or sulfuric acid
- the protective layer of chromium oxide forms on the surface of the laminate.
- This step is generally carried out immersing the manufactured product in baths containing nitric acid or mixtures of mineral acids (generally at lower concentrations with respect to the pickling step and with a lower content of the metal ions making up the steel) .
- nitric acid or mixtures of mineral acids generally at lower concentrations with respect to the pickling step and with a lower content of the metal ions making up the steel.
- there is also surface oxidation of the laminate that thus makes the finishing/passivation step superfluous.
- the pickling processes of the prior art have various drawbacks concerning their potential environmental impact, safety of the work spaces, operative control of the process as well as the equipment costs and the consumption of raw materials.
- the use of pickling baths of nitric acid and hydrofluoric acid leads to the formation of large quantities of nitrogen oxides (NOx) and waste water contaminated by nitrates and fluorinated compounds, which make it necessary to adopt specific measures to keep down gaseous emissions and to purify the waste water.
- NOx nitrogen oxides
- the quantity of contaminating compounds to be treated or disposed of depends on the quantity of material removed from the laminate in the baths containing nitric acid and hydrofluoric acid, a quantity that in turn depends - all other conditions being the same - on the duration of the treatment in these baths.
- Such durations are typically added to with the time necessary to carry out the chemical descaling in acid solution for the hot rolled strips (30-40 s) and that necessary for the electrolytic descaling in neutral or acid solution for cold annealed laminates (35-45 s) .
- strips of greater thickness with respect to those of the laminates able to be processed at the maximum speed, being heat treated in the annealing oven for longer times involve proportionally longer descaling and pickling steps.
- the process described in WO 00/15880 comprises an electrolytic pickling step in continuous current carried out in an aqueous solution of sulfuric acid in the presence of ions Fe 3+ ions.
- the process can also comprise steps of descaling (in baths of molten salts), chemical pickling (in solutions of H 2 SO and HF in the presence of Fe + and Fe + ions) and/or final passivation (in H 2 S0 4 and H 2 0 2 ) .
- EP 2102376 Al and JP 5222449 describe processes in which the annealing treatment that precedes the pickling is carried out in temperature and oxygen concentration conditions such as to reduce the amount of oxide that forms overall on the laminates.
- WO 03/052165 describes an electrolytic descaling process (in continuous current) of the laminates made of stainless steel carried out in a bath of sulfuric acid containing ferric ions, ferrous ions and hydrofluoric acid, followed by a chemical pickling treatment in aqueous solutions of sulfuric acid.
- the duration of the anode treatment in the electrolytic descaling process is correlated to the current density applied and to two parameters that are experimental in nature .
- EP 1307609 Al describes an electrolytic pickling process of laminates made of stainless steel carried out in a bath of sulfuric acid with an alternating current of frequency comprised between 40 and 70 Hz and with current density comprised between 10 and 250 A/dm 2 for a duration comprised between 3 s and 60 s.
- the electrolytic solution can also comprise variable concentrations of metal ions in solution deriving from the dissolution of steel, such as Fe, Cr, Ni, Mn, Mo, etc.
- the current density can preferably be selected as a function of the type of steels, for example, as follows:
- the frequency of the AC current is comprised in the range 5-150 Hz.
- the frequency is kept at a constant value during the treatment.
- it can also be varied as a function of the process requirements, for example to increase the quality of the treatment or to control the pickling speed as a function of the feeding speed of the laminate to the pickling plant.
- the method according to the invention also comprises a finishing and final passivation step (hereafter also just “finishing”) .
- This step which is generally carried out after having subjected the laminate to careful washing with water to eliminate the residues of sulfuric acid and iron oxides possibly still present on its surface, has the purpose of oxidising the surface of the laminate so as to form a protective layer of chromium oxide.
- the concentration of Fe 3+ ions is more preferably comprised in the range 45-90 g/1, whereas the concentration of Fe 2+ ions is more preferably comprised in the range 5-40 g/1.
- the concentration of Fe 3+ ions is more preferably comprised in the range 35-80 g/1, whereas the concentration of Fe 2+ ions is more preferably comprised in the range 5-40 g/1.
- the finishing solution comprises an aqueous solution of nitric acid, as single acid, also comprising Fe 3+ ions.
- concentration of nitric acid in the finishing solution is preferably comprised in the range 20-100 g/1, whereas that of the Fe 3+ ions is on the other hand comprised in the range 20-50 g/1.
- This finishing solution is particularly preferred in the case of ferritic cold rolled laminates.
- finishing solutions that are particularly preferred are those that do not comprise nitric acid, since they allow the environmental impact of the process to be reduced in terms of emissions of polluting gases (NOx) and nitrate and fluorinated compounds in the waste water.
- NOx polluting gases
- the finishing solution is kept at a temperature that can vary from 25°C to 65°C.
- the finishing step of the pickled laminate can be carried out by placing the laminate in contact with one or more of the aforementioned finishing solutions as a function of the type of steel, of the lamination process undergone and of the previous pickling steps.
- the composition of the scale depends strictly on the type of lamination undergone - hot or cold - and on possible annealing heat treatments to which the laminate has been subjected.
- the method according to the invention can comprise one or more further treatment steps.
- the treatment method can advantageously also comprise a chemical descaling step to promote the removal of scale in the subsequent electrolytic pickling step.
- the chemical descaling step is carried out by placing the laminate in contact with an aqueous solution comprising sulfuric acid and possibly metal ions (descaling solution) .
- the descaling solution comprises 200-280 g/1 of sulfuric acid and 30-50 g/l of dissolved metals.
- the chemical descaling step although possible, is generally omitted, since it is unnecessary.
- the duration of the treatment in DC current is comprised between 3 and 35 seconds, such a duration referring to the period in which a given surface portion of the laminate is anodically polarized.
- the treatment in DC current can be carried out before or after the treatment in AC current, preferably before.
- the treatment stages in AC and DC current can be carried out in the same tank or in separate tanks, arranged in series in the pickling plant.
- AC current and the duration of the anodic polarization obtained with the DC treatment is generally comprised between 0.15 and 1, preferably between 0.20 and 0.50.
- the method of the invention can also comprise the conventional steps (intermediate or preliminary) of washing and degreasing the surface of the laminate with suitable aqueous solutions containing surfactants or other additives.
- the washing steps (which can be carried out by immersion, spraying with water jets and possibly with the help of metallic brushes) have the purpose of eliminating the residues of the previous treatments from the surface and avoiding contamination of the solutions used in the subsequent steps of the method.
- Figure 1 schematically represents a possible embodiment of an apparatus in which it is possible to carry out the electrolytic pickling step according to the method of the invention.
- the apparatus wholly indicated with 10, comprises a treatment tank 12 suitable for containing the electrolytic solution SE and inside which the laminate 11 is made to pass in continuous along a direction and in the advancing sense indicated by the arrow F.
- the position of the laminate inside the treatment tank 12 is determined by the rollers 20 and 21 and by the pull applied on the strip.
- Each pair of electrodes 14 comprises at least one first electrode 15 facing one of the two faces of the laminate 11 and at least one second electrode 17 facing the other of the two faces of the laminate 11.
- the electrodes 15, 17, are also substantially equidistant from the laminate 11, each of them being at a distance Lc from the laminate in general comprised between 50 and 250 mm.
- the electrodes 15, 17 are arranged in a direction substantially parallel to the faces of the laminate along the path in the tank 12 and they extend substantially for the entire width La of the laminate (the width La is not shown in the figures) .
- the two electrodes 15, 17 of a pair of electrodes 14 are separated by a distance Lg preferably comprised between 100 and 500 mm.
- the electrodes 15, 17 of each pair of electrodes 14 are immersed in the electrolytic solution SE and can be associated with an electric power supply group (not shown in the figures) capable of delivering a continuous current DC or an alternating current AC at variable frequency.
- an electric power supply group capable of delivering a continuous current DC or an alternating current AC at variable frequency.
- a first preferred configuration is that for which the AC current is supplied to the electrodes 15, 17 so that the two electrodes of each pair 14 are with voltage in phase between them, so as to have, at a given moment, on both of the electrodes, a polarization of the same sign.
- there is at least one separator element made of an insulating material for example in the form of an immersing roller coated in plastic material or of a static separator made from plastic material (not shown in the figures) .
- the separators made from insulating material allow the formation of dispersed currents between electrodes of adjacent pairs that have opposite polarization to be reduced .
- a second preferred configuration provides that the electrodes 15 and 17 facing each other are connected to two different phases of the alternating current; in this case it is preferable for successive pairs of electrodes 14, if adjacent and not separated by immersing rollers and other insulating separators, to be connected to the same phases; pairs of electrodes separated by appropriate distance and by immersing rollers and insulating separators, on the other hand, will be connected to different phases so as to minimise the dispersed currents and, at the same time, avoid unbalanced loads on the power supply network.
- the resulting electric field has current lines that are substantially vertical and orthogonal to the surface of the laminate, which is thus passed through by the current along the thickness.
- the method according to the invention also contemplating carrying out a final finishing and passivation step of the laminates in mixtures containing nitric and hydrofluoric acid, determines a reduction in the environmental impact with respect to that typically observed in the processes of the prior art.
- the improved efficacy of the treatment method according to the present invention makes it possible to treat the laminates in plants of smaller dimensions with respect to the state of the art, being able to provide for shorter residency times of the laminate in contact with the pickling baths.
- EXAMPLES The method according to the present invention was applied to treat strips of stainless steel of different chemical composition, obtained through hot or cold rolling processes, possibly accompanied by annealing treatments.
- finishing and passivation section consisting of 2 tanks of length equal to 14 m each where the strip is immersed in the solution that is continually renewed through a recirculation system having an overall flow rate equal to 800 m 3 /h.
- the method according to the invention applied to the hot rolled laminates, has resulted in a significant reduction of the polluting substances to be treated.
- cooling section of overall length equal to 65 m, equipped with cooling means consisting of air blades combined with jets of water that intervene on the strip when it reaches temperatures below 200 °C up to a temperature of about 70°C;
- the efficacy of the method was evaluated by calculating the percentage amount of metal removed from the laminate and/or dissolved during each step with respect to the amount of metal removed and/or dissolved overall.
- the finishing treatments carried out in the conditions given in Table 4 proved sufficient to obtain a uniformly passivated surface.
- Such a treatment generated a significantly small amount of polluting products to be disposed of (muds containing nitrate, fluorinated compounds and emissions of NO x ) , since the amount of metal removed and/or dissolved in the finishing step is reduced to values of 20% by weight (L9) of the mass of steel removed and/or dissolved overall in the entire treatment.
- L9 20% by weight
- the amount of metal removed and/or dissolved in the nitric and/or hydrofluoric acid baths can reach 80% by weight of the amount pickled overall.
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
IT000493A ITMI20130493A1 (en) | 2013-03-29 | 2013-03-29 | METHOD TO PROCESS THE SURFACE OF A STAINLESS STEEL LAMINATE IN A CONTINUOUS SOLFORIC ACID SOLUTION |
PCT/IB2014/060230 WO2014155341A1 (en) | 2013-03-29 | 2014-03-27 | Method for treating in continuous the surface of a laminate made of stainless steel in a solution based on sulfuric acid |
Publications (2)
Publication Number | Publication Date |
---|---|
EP2978879A1 true EP2978879A1 (en) | 2016-02-03 |
EP2978879B1 EP2978879B1 (en) | 2017-11-08 |
Family
ID=48444515
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP14722742.5A Active EP2978879B1 (en) | 2013-03-29 | 2014-03-27 | Method for treating in continuous the surface of a laminate made of stainless steel in a solution based on sulfuric acid |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP2978879B1 (en) |
CN (1) | CN105143523B (en) |
BR (1) | BR112015020701B1 (en) |
IT (1) | ITMI20130493A1 (en) |
WO (1) | WO2014155341A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
BE1026906B1 (en) * | 2018-12-20 | 2020-07-22 | Aperam Stainless Belgium | Method for producing stainless steel sheet finished in at least three different ways |
BE1026907B1 (en) * | 2018-12-20 | 2020-07-22 | Aperam Stainless Belgium | Method for producing stainless steel sheet finished in at least three different ways |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN105040088A (en) * | 2015-08-11 | 2015-11-11 | 佛山市环宇新型材料有限公司 | Electrolytic decontamination device for strip steel |
CN107653485A (en) * | 2017-10-11 | 2018-02-02 | 徐州中泰能源科技有限公司 | A kind of green ironwork derusting method |
KR102286367B1 (en) * | 2019-11-11 | 2021-08-05 | 주식회사 포스코 | Manufacturing method of stainless steel for polymer fuel cell seperator |
KR102497442B1 (en) * | 2020-11-25 | 2023-02-08 | 주식회사 포스코 | Austenitic stainless steel for polymer fuel cell separator with improved contact resistance and manufacturing method thereof |
CN113337875B (en) * | 2021-04-02 | 2023-03-28 | 无锡透平叶片有限公司 | Iron-based deformation high-temperature alloy forging low-power flow line corrosion liquid and corrosion method thereof |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB8517606D0 (en) * | 1985-07-12 | 1985-08-21 | Bekaert Sa Nv | Cleaning by electrochemical pickling |
IT1302202B1 (en) | 1998-09-11 | 2000-07-31 | Henkel Kgaa | ELECTROLYTIC PICKLING PROCESS WITH SOLUTIONS FREE FROM ACIDONITRICO. |
IT1317896B1 (en) | 2000-08-10 | 2003-07-15 | Ct Sviluppo Materiali Spa | CONTINUOUS ELECTROLYTIC PICKLING METHOD OF METAL PRODUCTS CONCELLS POWERED BY ALTERNATING CURRENT. |
ES2232564T3 (en) * | 2000-12-18 | 2005-06-01 | Centro Sviluppo Materiali S.P.A. | DECAPADO AND UNINCUSTED ELECTROLYTIC CONTINUOUS STEEL CARBON AND STAINLESS STEEL |
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. |
ITRM20010747A1 (en) | 2001-12-19 | 2003-06-19 | Ct Sviluppo Materiali Spa | PROCEDURE WITH REDUCED ENVIRONMENTAL IMPACT AND RELATED PLANT FOR DESCALING, PICKLING AND FINISHING / PASSIVATING, IN A CONTINUOUS, INTEGRATED AND FL |
ITMI20062187A1 (en) | 2006-11-14 | 2008-05-15 | Sviluppo Materiali Spa | ANNEALING AND PICKLING PROCESS |
DE102008057151A1 (en) * | 2008-11-13 | 2010-05-27 | Henkel Ag & Co. Kgaa | Process for producing an electrolytically galvanized high strength steel sheet |
JP5222449B2 (en) | 2008-12-26 | 2013-06-26 | 三菱伸銅株式会社 | Slit method for plated copper strip and slitting device for plated copper strip |
IT1395853B1 (en) | 2009-09-30 | 2012-10-26 | Tenova Spa | SURFACE PREPARATION GROUP FOR METALLIC TAPE PRODUCTION LINES |
-
2013
- 2013-03-29 IT IT000493A patent/ITMI20130493A1/en unknown
-
2014
- 2014-03-27 EP EP14722742.5A patent/EP2978879B1/en active Active
- 2014-03-27 WO PCT/IB2014/060230 patent/WO2014155341A1/en active Application Filing
- 2014-03-27 CN CN201480018121.7A patent/CN105143523B/en active Active
- 2014-03-27 BR BR112015020701-4A patent/BR112015020701B1/en active IP Right Grant
Non-Patent Citations (1)
Title |
---|
See references of WO2014155341A1 * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
BE1026906B1 (en) * | 2018-12-20 | 2020-07-22 | Aperam Stainless Belgium | Method for producing stainless steel sheet finished in at least three different ways |
BE1026907B1 (en) * | 2018-12-20 | 2020-07-22 | Aperam Stainless Belgium | Method for producing stainless steel sheet finished in at least three different ways |
Also Published As
Publication number | Publication date |
---|---|
ITMI20130493A1 (en) | 2014-09-30 |
WO2014155341A1 (en) | 2014-10-02 |
BR112015020701A2 (en) | 2017-07-18 |
CN105143523A (en) | 2015-12-09 |
BR112015020701B1 (en) | 2021-08-24 |
EP2978879B1 (en) | 2017-11-08 |
CN105143523B (en) | 2018-06-19 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP2978879B1 (en) | Method for treating in continuous the surface of a laminate made of stainless steel in a solution based on sulfuric acid | |
KR100934303B1 (en) | Descaling, pickling and finishing / passivating methods and plants of stainless steel strips, and strips produced thereby | |
KR101289147B1 (en) | Environmental-Friendly and High Speed Pickling Process for Ferritic Stainless Cold Strip with Good Surface Quality | |
CA2849304C (en) | Stainless steel pickling in an oxidizing, electrolytic acid bath | |
EP1307609B1 (en) | Continuous electrolytic pickling method for metallic products using alternate current supplied cells | |
KR100650961B1 (en) | Process for electrolytic pickling using nitric acid-free solutions | |
KR101228730B1 (en) | High Speed Pickling Method for Surface Improvement of High Chromium Ferritic Stainless Cold Steel Strip | |
KR100696850B1 (en) | A descaling method for low Cr ferritic stainless steel | |
EP3029164B1 (en) | Method of treating a stainless steel strip, especially for a pickling treatment | |
JP6031606B2 (en) | High speed pickling process for producing austenitic stainless cold rolled steel sheet | |
EP2978878B1 (en) | Method for treating in continuous the surface of a laminate made of stainless steel in a solution based on hydrochloric acid | |
KR101359098B1 (en) | High speed pickling process for austenitic stainless cold strip | |
JP3792335B2 (en) | Finishing electrolytic pickling method in descaling of stainless steel strip | |
KR101382934B1 (en) | High Speed Pickling Process for Improving Corrosion Resistance of Austenitic Stainless Cold Strip | |
Hudson | Pickling and descaling | |
JP2517353B2 (en) | Descaling method for stainless steel strip | |
Covino et al. | Pickling of Stainless Steels--a Review | |
KR102300834B1 (en) | Ionic liquid for pickling stainless steel and pickling method for stainless steel using the same | |
KR101242990B1 (en) | Pickling process to improve surface quality of ferritic stainless cold strip | |
JPH09296285A (en) | Method for pickling austenitic stainless hot rolled steel strip |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 20150819 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
|
AX | Request for extension of the european patent |
Extension state: BA ME |
|
DAX | Request for extension of the european patent (deleted) | ||
GRAP | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOSNIGR1 |
|
INTG | Intention to grant announced |
Effective date: 20170530 |
|
GRAS | Grant fee paid |
Free format text: ORIGINAL CODE: EPIDOSNIGR3 |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
|
REG | Reference to a national code |
Ref country code: GB Ref legal event code: FG4D |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: EP Ref country code: AT Ref legal event code: REF Ref document number: 944242 Country of ref document: AT Kind code of ref document: T Effective date: 20171115 |
|
REG | Reference to a national code |
Ref country code: IE Ref legal event code: FG4D |
|
REG | Reference to a national code |
Ref country code: DE Ref legal event code: R096 Ref document number: 602014016877 Country of ref document: DE |
|
REG | Reference to a national code |
Ref country code: NL Ref legal event code: FP |
|
REG | Reference to a national code |
Ref country code: SE Ref legal event code: TRGR |
|
REG | Reference to a national code |
Ref country code: LT Ref legal event code: MG4D Ref country code: FR Ref legal event code: PLFP Year of fee payment: 5 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: NO Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20180208 Ref country code: LT Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20171108 Ref country code: ES Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20171108 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: HR Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20171108 Ref country code: RS Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20171108 Ref country code: LV Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20171108 Ref country code: BG Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20180208 Ref country code: IS Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20180308 Ref country code: GR Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20180209 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: CZ Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20171108 Ref country code: DK Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20171108 Ref country code: CY Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20171108 Ref country code: EE Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20171108 Ref country code: SK Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20171108 |
|
REG | Reference to a national code |
Ref country code: DE Ref legal event code: R097 Ref document number: 602014016877 Country of ref document: DE |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: RO Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20171108 Ref country code: SM Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20171108 Ref country code: PL Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20171108 |
|
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed |
Effective date: 20180809 |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: PL |
|
GBPC | Gb: european patent ceased through non-payment of renewal fee |
Effective date: 20180327 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: MC Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20171108 Ref country code: SI Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20171108 |
|
REG | Reference to a national code |
Ref country code: IE Ref legal event code: MM4A |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: LU Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20180327 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: IE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20180327 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: LI Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20180331 Ref country code: GB Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20180327 Ref country code: CH Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20180331 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: MT Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20180327 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: TR Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20171108 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: PT Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20171108 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: MK Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20171108 Ref country code: HU Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT; INVALID AB INITIO Effective date: 20140327 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: AL Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20171108 |
|
REG | Reference to a national code |
Ref country code: AT Ref legal event code: UEP Ref document number: 944242 Country of ref document: AT Kind code of ref document: T Effective date: 20171108 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 20230327 Year of fee payment: 10 Ref country code: FI Payment date: 20230327 Year of fee payment: 10 Ref country code: AT Payment date: 20230303 Year of fee payment: 10 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: SE Payment date: 20230315 Year of fee payment: 10 Ref country code: IT Payment date: 20230321 Year of fee payment: 10 Ref country code: BE Payment date: 20230327 Year of fee payment: 10 |
|
P01 | Opt-out of the competence of the unified patent court (upc) registered |
Effective date: 20230508 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: NL Payment date: 20240326 Year of fee payment: 11 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: AT Payment date: 20240304 Year of fee payment: 11 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FI Payment date: 20240325 Year of fee payment: 11 Ref country code: DE Payment date: 20240327 Year of fee payment: 11 |