US3429792A - Method of electrolytically descaling and pickling steel - Google Patents
Method of electrolytically descaling and pickling steel Download PDFInfo
- Publication number
- US3429792A US3429792A US567078A US3429792DA US3429792A US 3429792 A US3429792 A US 3429792A US 567078 A US567078 A US 567078A US 3429792D A US3429792D A US 3429792DA US 3429792 A US3429792 A US 3429792A
- Authority
- US
- United States
- Prior art keywords
- acid
- descaling
- pickling
- solution containing
- ferric chloride
- 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.)
- Expired - Lifetime
Links
- 238000000034 method Methods 0.000 title description 40
- 238000005554 pickling Methods 0.000 title description 14
- 229910000831 Steel Inorganic materials 0.000 title description 4
- 239000010959 steel Substances 0.000 title description 4
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 15
- 239000000243 solution Substances 0.000 description 15
- 229910021578 Iron(III) chloride Inorganic materials 0.000 description 13
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 description 13
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 12
- 239000002253 acid Substances 0.000 description 11
- 229910001220 stainless steel Inorganic materials 0.000 description 11
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 10
- VCJMYUPGQJHHFU-UHFFFAOYSA-N iron(3+);trinitrate Chemical compound [Fe+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O VCJMYUPGQJHHFU-UHFFFAOYSA-N 0.000 description 10
- 229910017604 nitric acid Inorganic materials 0.000 description 9
- 239000010935 stainless steel Substances 0.000 description 9
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 8
- 239000007864 aqueous solution Substances 0.000 description 8
- 229910052938 sodium sulfate Inorganic materials 0.000 description 8
- 235000011152 sodium sulphate Nutrition 0.000 description 8
- 229910052751 metal Inorganic materials 0.000 description 7
- 239000002184 metal Substances 0.000 description 7
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 6
- 239000000758 substrate Substances 0.000 description 6
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 5
- FEWJPZIEWOKRBE-UHFFFAOYSA-N Tartaric acid Natural products [H+].[H+].[O-]C(=O)C(O)C(O)C([O-])=O FEWJPZIEWOKRBE-UHFFFAOYSA-N 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 229910052708 sodium Inorganic materials 0.000 description 5
- 239000011734 sodium Substances 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 239000011975 tartaric acid Substances 0.000 description 5
- 235000002906 tartaric acid Nutrition 0.000 description 5
- 239000002699 waste material Substances 0.000 description 5
- FEWJPZIEWOKRBE-JCYAYHJZSA-N Dextrotartaric acid Chemical compound OC(=O)[C@H](O)[C@@H](O)C(O)=O FEWJPZIEWOKRBE-JCYAYHJZSA-N 0.000 description 4
- 239000003792 electrolyte Substances 0.000 description 4
- 230000007935 neutral effect Effects 0.000 description 4
- PUZPDOWCWNUUKD-UHFFFAOYSA-M sodium fluoride Chemical compound [F-].[Na+] PUZPDOWCWNUUKD-UHFFFAOYSA-M 0.000 description 4
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 3
- 150000008043 acidic salts Chemical class 0.000 description 3
- 238000004090 dissolution Methods 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Inorganic materials [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 description 3
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- 229910001959 inorganic nitrate Inorganic materials 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 159000000001 potassium salts Chemical class 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- -1 sodium fluoride Chemical class 0.000 description 2
- 235000013024 sodium fluoride Nutrition 0.000 description 2
- 239000011775 sodium fluoride Substances 0.000 description 2
- 239000004317 sodium nitrate Substances 0.000 description 2
- 235000010344 sodium nitrate Nutrition 0.000 description 2
- 239000002912 waste gas Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000005868 electrolysis reaction Methods 0.000 description 1
- 150000002222 fluorine compounds Chemical class 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 229910000040 hydrogen fluoride Inorganic materials 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 208000020442 loss of weight Diseases 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 150000002823 nitrates Chemical class 0.000 description 1
- GQPLMRYTRLFLPF-UHFFFAOYSA-N nitrous oxide Inorganic materials [O-][N+]#N GQPLMRYTRLFLPF-UHFFFAOYSA-N 0.000 description 1
- XAEFZNCEHLXOMS-UHFFFAOYSA-M potassium benzoate Chemical compound [K+].[O-]C(=O)C1=CC=CC=C1 XAEFZNCEHLXOMS-UHFFFAOYSA-M 0.000 description 1
- OTYBMLCTZGSZBG-UHFFFAOYSA-L potassium sulfate Chemical compound [K+].[K+].[O-]S([O-])(=O)=O OTYBMLCTZGSZBG-UHFFFAOYSA-L 0.000 description 1
- 229910052939 potassium sulfate Inorganic materials 0.000 description 1
- 239000001120 potassium sulphate Substances 0.000 description 1
- 235000011151 potassium sulphates Nutrition 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
- B23H3/00—Electrochemical machining, i.e. removing metal by passing current between an electrode and a workpiece in the presence of an electrolyte
- B23H3/08—Working media
Definitions
- the present invention relates to a novel process for descaling stainless steel surfaces by means of which the scales on the exposed surfaces of stainless steels of various kinds of shapes such as sheets and wires, may be removed very effectively.
- the surface of the metal substrate should be dissolved to a slight extent so as to eliminate that various kinds of surface scratches formed lit) 3,429,792 Patented Feb. 25, 1969 ice during the rolling. Accordingly it is desirable to impart to the solution such an effect that the surface of the metal substrate can be dissolved to an appropriate degree by means of the solution.
- the present process is an improvement over the prior art processes referred to.
- the process according to the present invention is characterized in that, in a first step, the electrolytic treatment is effected by using an aqueous solution containing a neutral salt, such as the sodium and potassium salts of sulfuric acid or nitric acid as the main component while, in a second step, the stainless steel object is immersed in, sprayed with or otherwise contacted by, an aqueous solution containing ferric chloride as the main component.
- the descaling is mainly effected in the first step although only a neutral or weakly acidic salt, without resorting to a strong acid as in the prior art methods is used.
- the descaling is effectively and rapidly concluded in the second step by attack on the surface of the metal substrate from which the scale has been removed, and by dissolution of said surface to an appropriate degree in a manner of chemical abrasion.
- the electrolysis was conducted with a graphite plate as cathode and a. stainless steel as anode, at an electrolyte concentration of 20% Na SO at a bath temperature of 70 C. and with a current density of 7 a./dm.
- the pickling was conducted by means of a solution containing ferric chloride corresponding to 8% FeCl by weight of the solution and ferric nitrate corresponding to 5% N0 by weight of the solution. The solution was adjusted to a pH of 1 and heated to a temperature of 7 0 C.
- one more embodiment is set forth as follows.
- a solution containing sodium sulphate and additionally 1% of sodium fluoride there were employed a solution containing sodium sulphate and additionally 1% of sodium fluoride, and another solution containing said components together with 1% of tartaric acid heated at a temperature of 70 C., and with a current density of 7 a./cm.
- the pickling procedure was conducted with a solution containing ferric chloride corresponding to 8% FeCl by weight and ferric nitrate corresponding to N0 by weight.
- the solution was adjusted to a pH of 1 and heated to a temperature of 70 C.
- the scope of conditions described in the said preceding applications gives satisfactory results.
- concentration of sodium sulphate or nitrate in the first step a concentration of more than 2% thus gives satisfactory results.
- the additional soluble fluoride as accelerator a concentration between 0.1% and thereof is employed with success.
- tartaric acid or citric acid as complex-salt forming substance, a concentration of less than 10% is suitable.
- a solution containing ferric chloride of from 6.5% to calculated as FeCl together with nitric acid or nitrates, such as ferric nitrate and sodium nitrate, of from 5% to 10% calculated as N0 is employed with complete success.
- the process of the present invention is thus characterized in that an electrolytic treatment is conducted with an aqueous solution containing more than 2% of sodium or potassium sulphate or nitrate as solute together with one or more accelerators such as a soluble fluoride, of a concentration from 0.1% to 10% and a complex-salt forming substance such as tartaric acid or citric acid of a concentration of less than 10%.
- a pickling treatment is effected by contacting the articles with a solution containing ferric chloride at a concentration between 6.5% and 15 calculated as FeCl together with nitric acid or inorganic nitrate at a concentration between 5% and 10% calculated as N0 so as to carry out the removal of oxide scales on the surfaces of stainless steels.
- the descaling may thus be performed very elfectively predominantly in the first step by means of a neutral or weakly acidic salt and without resorting to any strong acid as in the prior art methods.
- the exposed surface of the metal substrate is then dissolved directly and rapidly to an appropriate extent in the second step, so that the process of the present invention is very eflicient and economical.
- a two-step process of descaling stainless steel surfaces comprising:
- step (2) hereafter, in a second step, pickling the steel article in an aqueous solution containing (a) about -15 by weight of ferric chloride and and (b) nitric acid or an inorganic nitrate of a concentration of about 5-10% by weight calculated as N0 2.
- aqueous solution containing (a) about -15 by weight of ferric chloride and and (b) nitric acid or an inorganic nitrate of a concentration of about 5-10% by weight calculated as N0 2.
- the electrolyte of step (1) contains less than 10% by weight of a complex-salt forming substance.
- a process as claimed in claim 2, wherein the complexsalt forming substance is tartaric acid or citric acid.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Mechanical Engineering (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4627865 | 1965-07-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3429792A true US3429792A (en) | 1969-02-25 |
Family
ID=12742747
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US567078A Expired - Lifetime US3429792A (en) | 1965-07-30 | 1966-07-22 | Method of electrolytically descaling and pickling steel |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US3429792A (de) |
| AT (1) | AT265808B (de) |
| GB (1) | GB1098715A (de) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2311112A1 (fr) * | 1975-05-13 | 1976-12-10 | Wennberg Ab C J | Procede de nettoyage electrochimique continu et discontinu de l'acier allie contamine par des huiles |
| US4012299A (en) * | 1976-04-01 | 1977-03-15 | Allegheny Ludlum Industries, Inc. | Metallic descaling system |
| FR2333611A1 (fr) * | 1975-12-05 | 1977-07-01 | United Technologies Corp | Electrolyte pour l'usinage electrochimique des superalliages a base de nickel |
| DE2924601A1 (de) * | 1978-06-21 | 1980-01-03 | Ppg Industries Inc | Verfahren zum behandeln eines metallkoerpers |
| US4276133A (en) * | 1978-09-21 | 1981-06-30 | Sumitomo Industries, Ltd. | Method for continuous electrolytic descaling of steel wire by non-contact current flow |
| US4618379A (en) * | 1982-09-21 | 1986-10-21 | Roberto Bruno | Method for the continuous annealing of steel strips |
| US4713154A (en) * | 1985-08-08 | 1987-12-15 | Kawasaki Steel Corporation | Continuous annealing and pickling method and apparatus for steel strips |
| US5292374A (en) * | 1988-11-15 | 1994-03-08 | Maschinenfabrik Andritz Actiengesellschft | Process and plant for pickling stainless steel strip |
| US5675880A (en) * | 1996-08-29 | 1997-10-14 | Bethlehem Steel Corporation | Descaling system for use in the manufacture of steel and corresponding method |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2220005A (en) * | 1988-06-28 | 1989-12-28 | Borsodi Vegyi Komb | Process for removing oxide layer and scale from metals and metal alloys |
| IT1255655B (it) * | 1992-08-06 | 1995-11-09 | Processo di decapaggio e passivazione di acciaio inossidabile senza impiego di acido nitrico |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE112341C (de) * | ||||
| US1337718A (en) * | 1918-09-03 | 1920-04-20 | Western Electric Co | Cleansing of ferrous and non-ferrous metals |
| US2565189A (en) * | 1949-03-15 | 1951-08-21 | Du Pont | Electropolishing steel |
| US2915444A (en) * | 1955-12-09 | 1959-12-01 | Enthone | Process for cleaning and plating ferrous metals |
| US3043758A (en) * | 1958-12-23 | 1962-07-10 | Ruthner Othmar | Process of electrolytically pickling alloy steels |
| US3304246A (en) * | 1963-12-26 | 1967-02-14 | Mitsubishi Heavy Ind Ltd | Method of electrolytically descaling steel including selective recovery of dissolved scale products |
-
1966
- 1966-07-22 US US567078A patent/US3429792A/en not_active Expired - Lifetime
- 1966-07-25 AT AT707966A patent/AT265808B/de active
- 1966-07-29 GB GB34300/66A patent/GB1098715A/en not_active Expired
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE112341C (de) * | ||||
| US1337718A (en) * | 1918-09-03 | 1920-04-20 | Western Electric Co | Cleansing of ferrous and non-ferrous metals |
| US2565189A (en) * | 1949-03-15 | 1951-08-21 | Du Pont | Electropolishing steel |
| US2915444A (en) * | 1955-12-09 | 1959-12-01 | Enthone | Process for cleaning and plating ferrous metals |
| US3043758A (en) * | 1958-12-23 | 1962-07-10 | Ruthner Othmar | Process of electrolytically pickling alloy steels |
| US3304246A (en) * | 1963-12-26 | 1967-02-14 | Mitsubishi Heavy Ind Ltd | Method of electrolytically descaling steel including selective recovery of dissolved scale products |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2311112A1 (fr) * | 1975-05-13 | 1976-12-10 | Wennberg Ab C J | Procede de nettoyage electrochimique continu et discontinu de l'acier allie contamine par des huiles |
| FR2333611A1 (fr) * | 1975-12-05 | 1977-07-01 | United Technologies Corp | Electrolyte pour l'usinage electrochimique des superalliages a base de nickel |
| US4012299A (en) * | 1976-04-01 | 1977-03-15 | Allegheny Ludlum Industries, Inc. | Metallic descaling system |
| DE2924601A1 (de) * | 1978-06-21 | 1980-01-03 | Ppg Industries Inc | Verfahren zum behandeln eines metallkoerpers |
| US4276133A (en) * | 1978-09-21 | 1981-06-30 | Sumitomo Industries, Ltd. | Method for continuous electrolytic descaling of steel wire by non-contact current flow |
| US4618379A (en) * | 1982-09-21 | 1986-10-21 | Roberto Bruno | Method for the continuous annealing of steel strips |
| US4713154A (en) * | 1985-08-08 | 1987-12-15 | Kawasaki Steel Corporation | Continuous annealing and pickling method and apparatus for steel strips |
| US5292374A (en) * | 1988-11-15 | 1994-03-08 | Maschinenfabrik Andritz Actiengesellschft | Process and plant for pickling stainless steel strip |
| US5675880A (en) * | 1996-08-29 | 1997-10-14 | Bethlehem Steel Corporation | Descaling system for use in the manufacture of steel and corresponding method |
| US5794658A (en) * | 1996-08-29 | 1998-08-18 | Bethlehem Steel Corporation | High energy pump system for use in the descaling of steel |
Also Published As
| Publication number | Publication date |
|---|---|
| GB1098715A (en) | 1968-01-10 |
| AT265808B (de) | 1968-10-25 |
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