US2488108A - Stainless steel pickling - Google Patents
Stainless steel pickling Download PDFInfo
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- US2488108A US2488108A US687973A US68797346A US2488108A US 2488108 A US2488108 A US 2488108A US 687973 A US687973 A US 687973A US 68797346 A US68797346 A US 68797346A US 2488108 A US2488108 A US 2488108A
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- stainless steel
- chlorate
- fluoride
- pickling
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- 229910001220 stainless steel Inorganic materials 0.000 title description 34
- 239000010935 stainless steel Substances 0.000 title description 33
- 238000005554 pickling Methods 0.000 title description 31
- XTEGARKTQYYJKE-UHFFFAOYSA-M Chlorate Chemical compound [O-]Cl(=O)=O XTEGARKTQYYJKE-UHFFFAOYSA-M 0.000 description 44
- 239000000203 mixture Substances 0.000 description 29
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 20
- 229940005989 chlorate ion Drugs 0.000 description 16
- 238000000034 method Methods 0.000 description 14
- 239000000243 solution Substances 0.000 description 13
- 230000008569 process Effects 0.000 description 11
- 239000002253 acid Substances 0.000 description 10
- 239000007864 aqueous solution Substances 0.000 description 9
- GPRLSGONYQIRFK-UHFFFAOYSA-N hydron Chemical compound [H+] GPRLSGONYQIRFK-UHFFFAOYSA-N 0.000 description 9
- 239000007787 solid Substances 0.000 description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 9
- 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 8
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 8
- 239000011260 aqueous acid Substances 0.000 description 8
- 229910000831 Steel Inorganic materials 0.000 description 7
- -1 fluoride ions Chemical class 0.000 description 7
- 229910052708 sodium Inorganic materials 0.000 description 7
- 239000011734 sodium Substances 0.000 description 7
- 239000010959 steel Substances 0.000 description 7
- BZSXEZOLBIJVQK-UHFFFAOYSA-N 2-methylsulfonylbenzoic acid Chemical compound CS(=O)(=O)C1=CC=CC=C1C(O)=O BZSXEZOLBIJVQK-UHFFFAOYSA-N 0.000 description 6
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 6
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 6
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 6
- 238000005282 brightening Methods 0.000 description 6
- 150000004673 fluoride salts Chemical class 0.000 description 6
- PUZPDOWCWNUUKD-UHFFFAOYSA-M sodium fluoride Inorganic materials [F-].[Na+] PUZPDOWCWNUUKD-UHFFFAOYSA-M 0.000 description 5
- 230000008901 benefit Effects 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- BFXAWOHHDUIALU-UHFFFAOYSA-M sodium;hydron;difluoride Chemical compound F.[F-].[Na+] BFXAWOHHDUIALU-UHFFFAOYSA-M 0.000 description 4
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 3
- 229910052804 chromium Inorganic materials 0.000 description 3
- 239000011651 chromium Substances 0.000 description 3
- 150000002222 fluorine compounds Chemical class 0.000 description 3
- SHXXPRJOPFJRHA-UHFFFAOYSA-K iron(iii) fluoride Chemical compound F[Fe](F)F SHXXPRJOPFJRHA-UHFFFAOYSA-K 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 229910052759 nickel Inorganic materials 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- 235000013024 sodium fluoride Nutrition 0.000 description 3
- 239000011775 sodium fluoride Substances 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 2
- 229910052783 alkali metal Inorganic materials 0.000 description 2
- 150000001768 cations Chemical class 0.000 description 2
- 231100001261 hazardous Toxicity 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 239000011572 manganese Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- NROKBHXJSPEDAR-UHFFFAOYSA-M potassium fluoride Chemical compound [F-].[K+] NROKBHXJSPEDAR-UHFFFAOYSA-M 0.000 description 2
- WBHQBSYUUJJSRZ-UHFFFAOYSA-M sodium bisulfate Chemical compound [Na+].OS([O-])(=O)=O WBHQBSYUUJJSRZ-UHFFFAOYSA-M 0.000 description 2
- 229910000342 sodium bisulfate Inorganic materials 0.000 description 2
- 239000008247 solid mixture Substances 0.000 description 2
- 239000001117 sulphuric acid Substances 0.000 description 2
- 235000011149 sulphuric acid Nutrition 0.000 description 2
- 101150106671 COMT gene Proteins 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- KEAYESYHFKHZAL-UHFFFAOYSA-N Sodium Chemical compound [Na] KEAYESYHFKHZAL-UHFFFAOYSA-N 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910001515 alkali metal fluoride Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- DNEHKUCSURWDGO-UHFFFAOYSA-N aluminum sodium Chemical compound [Na].[Al] DNEHKUCSURWDGO-UHFFFAOYSA-N 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 229940068911 chloride hexahydrate Drugs 0.000 description 1
- 229910001610 cryolite Inorganic materials 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 229940044631 ferric chloride hexahydrate Drugs 0.000 description 1
- VOAPTKOANCCNFV-UHFFFAOYSA-N hexahydrate;hydrochloride Chemical compound O.O.O.O.O.O.Cl VOAPTKOANCCNFV-UHFFFAOYSA-N 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- NQXWGWZJXJUMQB-UHFFFAOYSA-K iron trichloride hexahydrate Chemical compound O.O.O.O.O.O.[Cl-].Cl[Fe+]Cl NQXWGWZJXJUMQB-UHFFFAOYSA-K 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- VKJKEPKFPUWCAS-UHFFFAOYSA-M potassium chlorate Chemical compound [K+].[O-]Cl(=O)=O VKJKEPKFPUWCAS-UHFFFAOYSA-M 0.000 description 1
- 235000003270 potassium fluoride Nutrition 0.000 description 1
- 239000011698 potassium fluoride Substances 0.000 description 1
- ZLMJMSJWJFRBEC-OUBTZVSYSA-N potassium-40 Chemical compound [40K] ZLMJMSJWJFRBEC-OUBTZVSYSA-N 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 229910021653 sulphate ion Inorganic materials 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
- C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
- C23G1/08—Iron or steel
Definitions
- My process for the pickling of stainless steel involves treatment of the stainless steel objects having oxide scale with an aqueous solution containing suitable concentrations of hydrogen ion, chlorate ion and fluoride ion furnished by a fluoride salt, namely at least about 0.01 percent by weight of hydrogen ion, at least about 0.1 percent by weight of chlorate ion, and at least about 0.5 percent by weight of such fluoride ion. Since both fluoride ion and chlorate ion are furnished by salts in my bath, it is a characteristic of my bath that its content of cations other than hydrogen ion (e. g. metal cations) is always greater than its content of chlorate ion, on the basis of ionic equiv alents, and important advantages appear to follow from this.
- a fluoride salt namely at least about 0.01 percent by weight of hydrogen ion, at least about 0.1 percent by weight of chlorate ion, and at least about 0.5 percent by weight of such fluoride i
- an upper limit of about 6 percent by weight concentration is suggested on economic grounds, i. e., more than 6 percent by weight of the ion may be employed, but does not seem to add to the efficacy of the bath, and in some instances such high concentrations may cause excessive attack on the metal.
- the minimum concentration of chlorate ion at least 0.1 percent by weight is important at the start of the operation, i. e., it is important to add at least this amount in the preparation of a new pickling bath.
- composition and process of my in- Example 1 vention have the important commercial advantage that a single bath may accomplish both 4 par s y wei ht of olid cry line so ium the primary and secondary pickling of stainless chlorate were well mixed with 4 parts by weight steel.
- the composition and process of my invenof solid finely divided sodium bifluoride are well mixed with 4 parts by weight steel.
- a soluble chlorate such
- the above described stainless steel objects were as sodium or potassium chlorate or other alkali immersed in the solution of sodium chlorate and metal chlorate in finely divided solid form is sodium bifluoride made as above described.
- the solid fluoride may adcompletely freed of oxide scale and were given vantageously be sodium or potassium fluoride or a bright finish, requiring no further pickling other alkali metal fluoride, or may be a fluoride treatment, within a period of 2 to 15 minutes. salt of acid reaction such as sodium or potassium 40 Exam 1 2 bifiuoride or other alkali metal bifluoride.
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
Description
Patented Nov. 15, 1949 STAINLESS STEEL PICKLIN G Frederick 0. Abbott, Harrington, N. J., assignor to The Pennsylvania Salt Manufacturing Company, Philadelphia, Pa., a corporation of Pennsylvania No Drawing. Application August 2, 1946, Serial No. 687,973
Claims. (Cl. 252-446) This invention relates to a new composition and process for the pickling of stainless steel.
Acid baths containing fluorides have been proposed heretofore for the pickling of stainless steel, e. g., for the removal of the oxide scale formed upon the processing of stainless steel articles in processes employing heat. Thus, aqueous solutions of ferric sulphate and hydrofluoric acid have been proposed for the pickling of stainless steel and aqueous solutions of nitric and hydrofluoric acids have been proposed as brightening baths in the pickling of stainless steel. However, compositions and processes heretofore suggested for the pickling of stainless steel have generally necessitated the handling of hydrofluoric acid by the steel treating plants, which is hazardous and expensive, and the procedures employed have usually required, for the bulk of the stainless steel processed commercially, the use of two successive pickling baths in order to produce a surface of desirable characteristics. Thus, of the two HF baths above mentioned the ferric sulphate-hydrofluoric mixture is employed industrially as a primary bath and is followed in the usual commercial practice by a secondary brightening bath consisting of the HNO3-HF mixture. Only in the case of a small proportion of the commercial stainless steel can the latter bath be used as the only pickling bath, and it has serious disadvantages, involving the handling, by steel fabricators, of such hazardous, corrosive and expensive materials as nitric and hydrofluoric acids.
I have now discovered a new stainless steel pickling composition which is surprisingly capable of accomplishing the complete pickling and brightening of stainless steel objects employing only the one bath, and making use of materials more readily handled by steel fabricators. The composition of my invention is a mixture of a. soluble chlorate and a soluble fluoride salt in proportion such that, on dissolving in an appropriate aqueous bath, hereinafter defined, the resulting solution when employed as a pickling and brightening bath for stainless steels, substantially completely obviates the objections to prior art processes. My composition is preferably a solid mixture of chlorate and fluoride salts, which upon solution in a dilute aqueous acid such as sulphuric or hydrochloric acid, or in the case of some species of my composition merely upon I solution in water, forms an acid bath containing chlorate and fluoride ions wh ch, as stated above, is remarkabl advantageous for the complete pickling and brightening of stainless steel.
My process for the pickling of stainless steel involves treatment of the stainless steel objects having oxide scale with an aqueous solution containing suitable concentrations of hydrogen ion, chlorate ion and fluoride ion furnished by a fluoride salt, namely at least about 0.01 percent by weight of hydrogen ion, at least about 0.1 percent by weight of chlorate ion, and at least about 0.5 percent by weight of such fluoride ion. Since both fluoride ion and chlorate ion are furnished by salts in my bath, it is a characteristic of my bath that its content of cations other than hydrogen ion (e. g. metal cations) is always greater than its content of chlorate ion, on the basis of ionic equiv alents, and important advantages appear to follow from this.
In determining suitable concentration ranges for the chlorate ion, an upper limit of about 6 percent by weight concentration is suggested on economic grounds, i. e., more than 6 percent by weight of the ion may be employed, but does not seem to add to the efficacy of the bath, and in some instances such high concentrations may cause excessive attack on the metal. With respect to the minimum concentration of chlorate ion, at least 0.1 percent by weight is important at the start of the operation, i. e., it is important to add at least this amount in the preparation of a new pickling bath. However, I have found, that after pickling has proceeded for an appreciable time the concentration may decrease to a lower value, and may even become so low that the chlorate ion is substantially completely eliminated without appreciably deleteriously alfecting the action of the bath for a limited period of time. However, in the absence of chlorate ion the efiiciency of the bath may become somewhat lower, and therefore I have found it more advantageous to prevent the concentration from decreasing below the stated minimum value. With respect to the upper limit of fluoride ion, a value of about 6 percent by weight is also suggested for economic reasons, coupled with the extent of solubility of the fluoride compound in question. It is clear, therefore, that if the solubility permits, a larger concentration of the fluoride compond may be used, but for the usual applications herein contemplated is unnecessary. With respect to the concentration of hydrogen ion, while it is possible to go higher than about 0.5 percent by weight, I have found that a material increase in the concentration above this value does not appreciably increase the efficiency of the bath in pickling and brightening operations. I have also found that the concentration of hydrogen ion should be maintained at least 3 about 0.01 percent by weight in order to achieve the objects of my invention.
By employing the process and composition of my invention, efiective pickling of stainless steel ling of stainless steel. Otherwise, the concentration of hydrogen ion may be furnished by any of the readily available inexpensive commercial acids, e. g. sulphuric acid, hydrochloric acid, or nitric acid.
to produce a bright finish may be accomplished 5 much more economically than with the pickling The following examples are illustrative of the bath heretofore proposed. Moreover, as above composition and process of my invention: stated, the composition and process of my in- Example 1 vention have the important commercial advantage that a single bath may accomplish both 4 par s y wei ht of olid cry line so ium the primary and secondary pickling of stainless chlorate were well mixed with 4 parts by weight steel. The composition and process of my invenof solid finely divided sodium bifluoride. 8 parts tion have the further advantage that all types of by weight of the resulting mixture were disstainless steel may be pickled by this method and solved in 112 parts by weight of water containing by this bath, whereas in prior art practice it has 14 parts by weight of sulfuric acid. been found necessary to employe different types Stainless steel objects made from steel conof baths for different types of stainless steel. taining:
Object Carbon, Chromium, Nickel, Other Elements, Number Per Cent Per Cent Per Cent Per Cent oiostoaoo 17-19 8-10 Manganese 2.00 maximum.
.08 maximum.. 18-20 8-10 Do. .10 maximum. 16-18 10-14 Manganese and molybdenum 2-3. .12 maximum-- 14-18 Other important advantages in the composition were employed in this test. These objects conand process of my invention, such as ease in tained oxide scale consisting mainly of the oxides handling and reduction of hazard, have been dis- 0 of iron, chromium, and nickel, produced by the cussed above. 3 processing of the steel including the operations In a preferred composition prepared in accordof hot rolling and annealing. ance with my invention, a soluble chlorate such The above described stainless steel objects were as sodium or potassium chlorate or other alkali immersed in the solution of sodium chlorate and metal chlorate in finely divided solid form is sodium bifluoride made as above described. By blended with a soluble fluoride, also in finely this treatment the stainless steel objects were divided solid form. The solid fluoride may adcompletely freed of oxide scale and were given vantageously be sodium or potassium fluoride or a bright finish, requiring no further pickling other alkali metal fluoride, or may be a fluoride treatment, within a period of 2 to 15 minutes. salt of acid reaction such as sodium or potassium 40 Exam 1 2 bifiuoride or other alkali metal bifluoride. Other p e fluorides soluble in acid, e. g. ferric fluoride, may 4 parts by weight of solid crystalline sodium be employed, or in place of the simple fluorides chlorate were mixed well with 4 parts by weight complex fluorides soluble under the conditions of solid finely divided sodium bifluoride and 15 employed, e. g., cryolite, a sodium aluminum i'luparts of sodium acid sulfate. 23 parts by weight oride, may be employed. As above made clear, of the resulting mixture were dissolved in 91 parts in a composition suitable for making up a bath by weight of water containing 6 parts by weight initially, the chlorate and fluoride are employed of 93% sulfuric acid. in such proportions that when dissolved in water Stainless steel objects similar to those used in or dilute acid the solution will contain from Example 1 were immersed in this bath. Within about .02 to 12 parts by weight of chlorate ion 2 to 15 minutes the stainless steel objects were per part by weight of fluoride ion; a preferred completely freed of oxide scale and exhibited a composition will furnish, when dissolved in water bright surface requiring no further pickling. or dilute acid, from about A; to about 6 parts Exam Z 3 by Weight chlorate ion per part by weight fluoride p 8 ion, for example, a mixture of about 20 percent An aqueous pickling bath comprising sulfuric to about 80 percent by weight sodium chlorate, acid y e Sodium fl o de 5% y the balance consisting primarily of a sodium flu- Weight, Sodium chlorate 4% by Weight, and waoride such as sodium bifiuoride, in such a comt r 83% by Weight Was p p d by first mixing position. The resulting pickling bath is also a pulverized sodium fluoride and sodium chlorate, new composition coming within the scope of my and dissolving the mixture in acid containing invention. I have further found that for replenwater. ishing a used fluoride-chlorate pickling bath, a Stainless steel objects similar to those used composition furnishing from about 12 to 40 parts in Example 1 were immersed in this bath. Withby weight of chlorate ion per part fluoride ion is in 2 to 15 minutes the stainless steel objects were quite advantageous. 05 completely freed of oxide scale and exhibited a In employing the above described composition bright surface requiri n fur h r pi kl n for the pickling of stainless steel, the above de- Example 4 scribed mixture of solids may be dissolved in water or in a dilute aqueous solution of sulphuric An aqueous pi klin bath omprisin Sulfuric or hydrochloric acid. When the solid composifi d by weight, Sodium chlorate y tion contains an acid fluoride such as sodium biweight, sodium bifluoride 2% by weight, ferric fluoride, or some other solid added to furnish chloride hexahydrate 3.6% by weight, and water acidity, e. g. sodium acid sulfate, solutions of the 84.4% by weight was prepared by dissolving apcompositions in water alone may contain a sufiipropriate amounts of the various ingredients in cient concentration of hydrogen ion for the pickwater.
Stainless steel objects similar to those used in Example 1 were immersed in this bath. Within 2 to 15 minutes the stainless steel objects were completely freed of oxide scale and exhibited a bright surface requiring no further pickling.
Example 5 The same procedure and materials were used as in Example 4, except 2.5% by weight ferric fluoride was substituted for 3.6% by weight ferric chloride hexahydrate, the balance being water. Substantially identical results were obtained.
The term stainless steel is employed in the specification and claims to denote a ferrous alloy containing from about 8 to 30 percent chromium and from about 0 to 14 percent nickel.
Since many modifications are possible in the process and product of my invention as above described without departing from the scope of the invention, it is intended that the above description of my invention should be interpreted as illustrative, and the invention is not to be limited except as set forth in the claims which follow.
I claim:
1. A composition suitable for use in aqueous acid solution for the pickling of stainless steel, comprising a chlorate capable of furnishing chlorate ions in aqueous acid solution, and a fluoride salt capable of furnishing fluoride ions in aqueous acid solution, the chlorate and the fluoride being present in the composition in such proportion that from .02 to 40 parts by weight chlorate ion are furnished per part by weight of aqueous acid solution, the chlorate and the fluoride being present in the composition in such proportion that from .02 to 12 parts by weight chlorate ion are furnished per part by weight of fluoride ion in aqueous acid solution.
3. A pickling bath for removing oxide scale from stainless steel objects, consisting of an aqueous solution containing from about 0.01 to about 0.5 percent by weight hydrogen ion, from about 0.1 to about 6 percent by weight chlorate ion furnished by a chlorate soluble in said aqueous solution and from about 0.5 to about 6 percent by weight fluoride ion furnished by a fluoride salt soluble in said aqueous solution.
4. A solid composition suitable for production of an aqueous acid pickling solution for the pickling of stainless steel, comprising sodium chlorate and a sodium fluoride, the chlorate and the fluoride being present in the composition in the proportion that furnishes, in aqueous acid solution, from about to 6 parts by weight chlorate ion per part by weight fluoride ion.
5. A pickling bath for removing oxide scale from stainless steel objects, consisting of an aqueous solution containing from about 0.01 to 0.5% by weight of hydrogen ion, from about 0.1 to about 6% by weight of chlorate ion furnished by an alkali metal chlorate and from about 0.5 to about 6% by weight of fluoride ion furnished by a fluoride salt soluble in said aqueous solution.
FREDERICK C. ABBOTT.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 2,070,871 Stockton Feb. 16, 1937 2,395,694 Spence et a1 Feb. 26, 1946 2,408,424 Healy et a1. Oct. 1, 1946
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US687973A US2488108A (en) | 1946-08-02 | 1946-08-02 | Stainless steel pickling |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US687973A US2488108A (en) | 1946-08-02 | 1946-08-02 | Stainless steel pickling |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2488108A true US2488108A (en) | 1949-11-15 |
Family
ID=24762591
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US687973A Expired - Lifetime US2488108A (en) | 1946-08-02 | 1946-08-02 | Stainless steel pickling |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US2488108A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1033480B (en) * | 1952-11-07 | 1958-07-03 | Walter Eckhoff Dipl Ing | Pickling solution for pickling iron sheets from the enamelling |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2070871A (en) * | 1935-05-13 | 1937-02-16 | Udylite Company | Method of brightening metals |
| US2395694A (en) * | 1944-06-02 | 1946-02-26 | Hooker Electrochemical Co | Processes for removing oxide from the surface of metals |
| US2408424A (en) * | 1940-06-15 | 1946-10-01 | Monsanto Chemicals | Pickling steels |
-
1946
- 1946-08-02 US US687973A patent/US2488108A/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2070871A (en) * | 1935-05-13 | 1937-02-16 | Udylite Company | Method of brightening metals |
| US2408424A (en) * | 1940-06-15 | 1946-10-01 | Monsanto Chemicals | Pickling steels |
| US2395694A (en) * | 1944-06-02 | 1946-02-26 | Hooker Electrochemical Co | Processes for removing oxide from the surface of metals |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1033480B (en) * | 1952-11-07 | 1958-07-03 | Walter Eckhoff Dipl Ing | Pickling solution for pickling iron sheets from the enamelling |
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