US2662814A - Method and composition for chemically polishing metals - Google Patents
Method and composition for chemically polishing metals Download PDFInfo
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- US2662814A US2662814A US112840A US11284049A US2662814A US 2662814 A US2662814 A US 2662814A US 112840 A US112840 A US 112840A US 11284049 A US11284049 A US 11284049A US 2662814 A US2662814 A US 2662814A
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- acids
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- 238000005498 polishing Methods 0.000 title claims description 22
- 239000000203 mixture Substances 0.000 title claims description 19
- 238000000034 method Methods 0.000 title description 11
- 229910052751 metal Inorganic materials 0.000 title description 8
- 239000002184 metal Substances 0.000 title description 8
- 150000002739 metals Chemical class 0.000 title description 3
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims description 54
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 39
- 239000002253 acid Substances 0.000 claims description 36
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims description 27
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 21
- 229910001220 stainless steel Inorganic materials 0.000 claims description 20
- 239000010935 stainless steel Substances 0.000 claims description 17
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 15
- 229910017604 nitric acid Inorganic materials 0.000 claims description 14
- 150000007513 acids Chemical class 0.000 claims description 11
- 239000000126 substance Substances 0.000 claims description 11
- 239000000243 solution Substances 0.000 claims description 9
- 239000007864 aqueous solution Substances 0.000 claims description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 21
- 235000011167 hydrochloric acid Nutrition 0.000 description 19
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 12
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 10
- 239000003112 inhibitor Substances 0.000 description 7
- 229910052742 iron Inorganic materials 0.000 description 6
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 5
- 239000011651 chromium Substances 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- 230000009471 action Effects 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 4
- 229910052804 chromium Inorganic materials 0.000 description 4
- 229910052759 nickel Inorganic materials 0.000 description 4
- 239000011280 coal tar Substances 0.000 description 3
- 239000000470 constituent Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- -1 hydrofluoric agid Chemical compound 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- 238000007517 polishing process Methods 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 239000010963 304 stainless steel Substances 0.000 description 1
- 229910000599 Cr alloy Inorganic materials 0.000 description 1
- 229910000640 Fe alloy Inorganic materials 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- 229910000990 Ni alloy Inorganic materials 0.000 description 1
- 229910000589 SAE 304 stainless steel Inorganic materials 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 239000004480 active ingredient Substances 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 238000005282 brightening Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000001311 chemical methods and process Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000004519 grease Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910017464 nitrogen compound Inorganic materials 0.000 description 1
- 150000002830 nitrogen compounds Chemical class 0.000 description 1
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
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
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F3/00—Brightening metals by chemical means
- C23F3/04—Heavy metals
- C23F3/06—Heavy metals with acidic solutions
Definitions
- This invention relatesto a method and com-' position for chemically polishing metals, and relates particularly to the polishing of stainless steel ces.
- the prior methods for polishing and brightening stainless steel surfaces include'mechanical polishing and'bumng and electropolishing.
- electropolishing methods a chemical bath is used in combination with'an electric current to produce near mirror finishes on stainless steel.
- the use of chemical baths only without the use of electriccurrent has also been proposed, but the resulting surface has a grainy or satiny appearance as contrasted to a polished surface.
- these prior chemical baths brighten the stainless steel surfaces but do not produce a polished effect.
- Electropolishing while often producing satisfactory results, requires the use of expensive equipment and large quantities of electrical energy while mechanical polishing is diflicult because it involves extensive handling of the work resulting in high labor costs. Similarly mechanical polishing often cannot'be performed because of the intricate form and nature of the work requiring polishing. i
- a further advantage of this invention is that it can be used in connection with electro or mechanical polishing as a pretreatment thereby saving valuable time, materials, and labor by reducing the amount of mechanical or electropolishing required.
- stainless steel is meant to cover those steels being mainly alloys of iron, chromium and nickel, along with minor constituents; or of only iron andchromium along with minor constituents, 1 a
- the concentrations of acids are expressed on a weight basis of the acids with the acids being of strength.
- dilute baths on the other hand, is not so susceptible to time and temperature variations, nor does a small change in composition affect the quality of finish obtained, as for eX-. ample a slight dilution of the bath resulting when metals previously treated in some other bath, and retaining a quantity of moisture on their surfaces, are immersed in the polishing bath. Furthermore, a dilute bath is considerably less expensive than a concentrated bath.-
- an acid bath containing not over 30 to 35% total acidity, of which, it is essential that the m H bmwmd, or a mixture of phosphoric and s ids may be used in place 0 the phosphoric acid constituent.
- Active ingredients of the bath are nitric and hydrochloric acids; however, the presence of phosphoric acid or a mixture of phosphoric and sulfuric acids in substantial amounts is essential to ensure smooth chemical polishing rather than etching.
- the phosphoric acid or equivalent mixture con centration of the bath is reduced to the same concentration as either the nitric or hydrochloric acids or both, an inferior polish is obtained.
- the lower concentration of bath which I find generally effective is one of approximately 20% total acidity.
- nitric and hydrochloric acids should each be present in at least 2% by weight and as a maximum their combined weights should not exceed the total weight of phosphoric acid. Variations between these limits have in general produced good polishes.
- the preferred baths contain from about 15 to 25% by weight of phosphoric acid, 2 to 4% by weight ofnitric acid 2 to 5% by weight of hydrochloric acidfandthe remainder water. Part. or if desired all, of the phosphoric acid may be replaced with sulfuric acid.
- the metal to be polished is suspended in a hot acid bath of preferably not more than 210" F; temperature nor less thanlfiilg A temperature range of 180-190" F. is preferred. After considerable use the acid bath becomes depleted and. the polishing ability decreases.
- the bath may be replenished in several ways: (1) water losses resulting fromevaporation may be periodically replaced and the acidity of the bath improved by addition of fresh make-up acid without draining. any solution; (2) water losses and acid depletion may be periodically replaced by the addition of appropriate quantities of acid solution with. concurrent withdrawal of an amount of solution equivalent to the amount of upkeep acid added, or as another variation (3) equivalent to the amount of water and upkeep added.
- I may replace a portion or all of the phosphoric acid with sulfuric acid, though ordinarily the polished surface is not so bright as that obtained by using phosphoric acid without the sulfuric acid.
- I include a small portion of an inhibitor in the acid bath to inhibit the activity of the acids, satisfactory polishes are obtained with sulfuric acid.
- the preferred baths contain at least somev phosphoric acid.
- suitable inhibitors include the nitrogen containing derivatives of coal tar such as the mixture of inorganic salts of coal tar bases known as "Reilly No. 2," mixed coal tar hydrochloride bases reacted with an inorganic nitrogen compound known as Reilly No. 2, in-
- hibitor in the phosphoric acid bath since its inclusion does not impair the polishing action but in some cases improves it.
- up to 2.0% of the inhibitor may be used, but ordinarily the amount required will vary from about 0.5 to 1.0% by weight of the bath.
- the time required to produce a polished surface will vary somewhat, depending upon the composition and temperature of the bath, and type of metal surface to be polished, and the condition of the surface. For normal polishing the time required will ordinarily be from about 5 to 10 minutes. At a bath temperature of F., five minutes. is. ordinarily sufiicient for most articles, and in fact such period of time is preferred as it permits better control of polishing action than is possible with shorter periods of time. -Of course, if there is a large amount of scale present, the time required may exceed 10 minutes.
- Example 1 --A bath containing by weight of 23.9 parts phosphoric acid, 2.7 parts nitric acid, 2.2 parts hydrochloric acid, and 71.2 parts water was prepared. It was heated to and a sheet of No. 302 stainless steel was immersed for five minutes, resulting in a. bright semi-mirror finish. on the metal.
- Example 2 A bath containing by weight 3.9 parts phosphoric acid, 3.0 parts nitric acid, and 2.4 parts hydrochloric acid, and 91.7 parts water was prepared, and a sheet of, No. 302 stainless steel was immersed for five minutes at 180 F. There was evidence of polish, but the results were inferior to that of Example 1.
- Example 3 A similar bath to that of Example 2 was prepared except that the phosphoric acid was eliminated. The surface of a stainless steel sheet was etched, but there was no polish.
- Example 4.-A bath. composed of by weight, 15.0 parts phosphoric acid, 42 parts nitric acid, 2.3 parts hydrochloric acid, and 78.5 parts water, gave a bright semi-mirror finish to a piece of No. 302 stainless steel sheet when used for five minutes at 180 F.
- Example 5 A bath composed of by weight 14.9 parts phosphoric acid, 2.8 parts nitric acid, 4.6 parts hydrochloric acid, and 77.7 parts water, gave a bright finish to a sheet of No. 302 stainless steel.
- Example 6 A portion of the phosphoric acid was replaced by sulfuric acid resulting in a bath of the following composition by weight: 3.2 parts phosphoric acid, 11.7 parts sulfuricncid, 3.5 parts nitric a cid, and 2.3'partshydrochloric acid?-1% mills No. 22 inhibitor was added, the remainder being water.
- the polish obtained was equally as good as in the previous example.
- the phosphoric and nitric acids may be supplied in a coneentrated mixture, and then mixed with water and hydrochloric acid and an inhibitor, if any is used, to make the treating bath.
- This concentrated mixture preferably contains from about 60 to 75% by weight of phosphoric acid, about 8 to 12% of nitric acid, and the balance water.
- An excellent concentrated mixture is one containing about 65% of phosphoric acid, 9% of nitric acid and 26% of water.
- a bath for the chemical polishing of stainless steel surfaces and the removal of scale therefrom consisting essentially of an aqueous solution having a total acid concentration between 20 and 35% by weight and including nitric acid, hydrochloric acid, and between about 15 to 25% by weight of the total solution of an acid of the class consisting of phosphoric acid, sulfp rigacid, and a mixture of phosphoric and sulfuric acids, at least 2% of the total solution being acid and at least 2% being hydrochloric acid, with the combined weight of the nitric and hydrochloric acids being not more than the total weight of said class.
- a bath for the chemical polishing of stainless steel surfaces and the removal of scale therefrom consisting essentially of about 15 to 25% by weight of phosphoric acid, about 2 to 6 4% of nitric acid, about 2 to 5% of hydrochloric acid, and the remainder being essentially water.
- a composition of matter consisting of about 24% by weight of phosphoric acid, about 3% of nitric acid, about 3% of hydrochloric acid, and the remainder water.
- the method of polishing a stainless steel surface which comprises contacting said surface with an acid solution consisting essentially of about 15 to 25% by weight of phosphoric acid, about 2 to 4% of nitric acid, about 2 to 5% of hydrochloric acid, and the remainder water for a period of time and at a temperature suflicient to remove scale and produce a bright polished surface.
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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)
- ing And Chemical Polishing (AREA)
Description
Patented Dec. 15, 1 953 John R. Swihart, Chicago Heights, 111., assignor to The Diversey Corporation, a corporation of Illinois No Drawing. Application August 27, 1949,
- Serial-No.112,840 y 9 Claims. 1
This invention relatesto a method and com-' position for chemically polishing metals, and relates particularly to the polishing of stainless steel ces. The prior methods for polishing and brightening stainless steel surfaces include'mechanical polishing and'bumng and electropolishing. In electropolishing methods a chemical bath is used in combination with'an electric current to produce near mirror finishes on stainless steel. The use of chemical baths only without the use of electriccurrent has also been proposed, but the resulting surface has a grainy or satiny appearance as contrasted to a polished surface. Thus these prior chemical baths brighten the stainless steel surfaces but do not produce a polished effect. Electropolishing, while often producing satisfactory results, requires the use of expensive equipment and large quantities of electrical energy while mechanical polishing is diflicult because it involves extensive handling of the work resulting in high labor costs. Similarly mechanical polishing often cannot'be performed because of the intricate form and nature of the work requiring polishing. i
It is the purpose of the present invention to overcome these disadvantages and to provide a method and chemical polishing composition that produces a polished surface which nearly approaches that obtained by mechanical or electropolishing methods, yet employs only a simple chemical process, easily controlled, and utilizing commercially available materials. A further advantage of this invention is that it can be used in connection with electro or mechanical polishing as a pretreatment thereby saving valuable time, materials, and labor by reducing the amount of mechanical or electropolishing required.
No unusual or specially constructed equipment is required for this invention. Readily available acid resistant containers and heating elements are the only materials required. The invention is particularly well adapted to the removal of heat scale, dirt, and grease since it leaves the surface in polished condition usually requiring no further treatment. l
Byway of definition of terms used in the description of this polishing process, it should be 4 understood that the term "stainless steel is meant to cover those steels being mainly alloys of iron, chromium and nickel, along with minor constituents; or of only iron andchromium along with minor constituents, 1 a
In the examples and the claims, the concentrations of acids are expressed on a weight basis of the acids with the acids being of strength.
I have discovered that acid compositions composed of phosphoric, nitric, and h drochloric acids have theeiicellemperty m to chemically polish stainless steels, a property not existing in mixtures of other acids. For example, I have tried baths composed of onl hosphoric acid, hydrochloric acid an l w aE";% ydrocmacidmand water; phos horic acid, nitric acid and water; mum acid, hydrochloric acid, and water; nitri'm ac1,hy roliiEFc afiid and water; sulfuric acid, hydrofluoric acid,
0 romic acid and wager; nitric acid, hydrofluoric agid, hydrochloric acid and water; and other combinations of acids both mentrated and dilute. None of the above compositions pro duced a near mirror finish as was produced by my invention.
In the carrying out of my invention I prefer to use the new acid bath in a dilute form. While it is possible to obtain a chemical polish on stainless steels immersed in a concentrated bath of these acids, the action is very rapid and hard to control. Both time and temperature of immersion of the metal in such a bath is critical and too long an immersion will result in rapid wearing away and pitting of the metal.
The action of dilute baths on the other hand, is not so susceptible to time and temperature variations, nor does a small change in composition affect the quality of finish obtained, as for eX-. ample a slight dilution of the bath resulting when metals previously treated in some other bath, and retaining a quantity of moisture on their surfaces, are immersed in the polishing bath. Furthermore, a dilute bath is considerably less expensive than a concentrated bath.-
Accordingly I prefer to use an acid bath containing not over 30 to 35% total acidity, of which, it is essential that the m H bmwmd, or a mixture of phosphoric and s ids may be used in place 0 the phosphoric acid constituent. Active ingredients of the bath are nitric and hydrochloric acids; however, the presence of phosphoric acid or a mixture of phosphoric and sulfuric acids in substantial amounts is essential to ensure smooth chemical polishing rather than etching. When the phosphoric acid or equivalent mixture con centration of the bath is reduced to the same concentration as either the nitric or hydrochloric acids or both, an inferior polish is obtained. The lower concentration of bath which I find generally effective is one of approximately 20% total acidity.
For best chemical polishing I have found that the nitric and hydrochloric acids should each be present in at least 2% by weight and as a maximum their combined weights should not exceed the total weight of phosphoric acid. Variations between these limits have in general produced good polishes. The preferred baths, contain from about 15 to 25% by weight of phosphoric acid, 2 to 4% by weight ofnitric acid 2 to 5% by weight of hydrochloric acidfandthe remainder water. Part. or if desired all, of the phosphoric acid may be replaced with sulfuric acid. Onebath that has given excellent results'cb'nslsted essentially of about 24% phosphoric acid about 3% nitric acid, about 3% hydrochloric acid and the remainder water.
The metal to be polished is suspended in a hot acid bath of preferably not more than 210" F; temperature nor less thanlfiilg A temperature range of 180-190" F. is preferred. After considerable use the acid bath becomes depleted and. the polishing ability decreases. The bath may be replenished in several ways: (1) water losses resulting fromevaporation may be periodically replaced and the acidity of the bath improved by addition of fresh make-up acid without draining. any solution; (2) water losses and acid depletion may be periodically replaced by the addition of appropriate quantities of acid solution with. concurrent withdrawal of an amount of solution equivalent to the amount of upkeep acid added, or as another variation (3) equivalent to the amount of water and upkeep added.
When method 1 is used there is a gradual increase in the acidity of the bath, in method 2 this increase in acidity is. more gradual while in method 3 the acidity of the bath remains very uniform. Many variations and modifications of the above procedure may be employed, as for example continuous addition of upkeep acid solution and removal of used acid, without affecting the quality of polish obtained.
I may replace a portion or all of the phosphoric acid with sulfuric acid, though ordinarily the polished surface is not so bright as that obtained by using phosphoric acid without the sulfuric acid. However, if I include a small portion of an inhibitor in the acid bath to inhibit the activity of the acids, satisfactory polishes are obtained with sulfuric acid. The preferred baths, however, contain at least somev phosphoric acid. Examples of suitable inhibitors that may be used include the nitrogen containing derivatives of coal tar such as the mixture of inorganic salts of coal tar bases known as "Reilly No. 2," mixed coal tar hydrochloride bases reacted with an inorganic nitrogen compound known as Reilly No. 2, in-
hibitor in the phosphoric acid bath since its inclusion does not impair the polishing action but in some cases improves it. In general, up to 2.0% of the inhibitor may be used, but ordinarily the amount required will vary from about 0.5 to 1.0% by weight of the bath.
The time required to produce a polished surface will vary somewhat, depending upon the composition and temperature of the bath, and type of metal surface to be polished, and the condition of the surface. For normal polishing the time required will ordinarily be from about 5 to 10 minutes. At a bath temperature of F., five minutes. is. ordinarily sufiicient for most articles, and in fact such period of time is preferred as it permits better control of polishing action than is possible with shorter periods of time. -Of course, if there is a large amount of scale present, the time required may exceed 10 minutes.
The following examples are given for illustration only and it is not intended that the claims be limited to the specific concentrations of these examples.
Example 1.--A bath containing by weight of 23.9 parts phosphoric acid, 2.7 parts nitric acid, 2.2 parts hydrochloric acid, and 71.2 parts water was prepared. It was heated to and a sheet of No. 302 stainless steel was immersed for five minutes, resulting in a. bright semi-mirror finish. on the metal.
Example 2.A bath containing by weight 3.9 parts phosphoric acid, 3.0 parts nitric acid, and 2.4 parts hydrochloric acid, and 91.7 parts water was prepared, and a sheet of, No. 302 stainless steel was immersed for five minutes at 180 F. There was evidence of polish, but the results were inferior to that of Example 1.
Example 3.A similar bath to that of Example 2 was prepared except that the phosphoric acid was eliminated. The surface of a stainless steel sheet was etched, but there was no polish.
Example 4.-A bath. composed of by weight, 15.0 parts phosphoric acid, 42 parts nitric acid, 2.3 parts hydrochloric acid, and 78.5 parts water, gave a bright semi-mirror finish to a piece of No. 302 stainless steel sheet when used for five minutes at 180 F.
Example 5.-A bath composed of by weight 14.9 parts phosphoric acid, 2.8 parts nitric acid, 4.6 parts hydrochloric acid, and 77.7 parts water, gave a bright finish to a sheet of No. 302 stainless steel.
Example 6.-A portion of the phosphoric acid was replaced by sulfuric acid resulting in a bath of the following composition by weight: 3.2 parts phosphoric acid, 11.7 parts sulfuricncid, 3.5 parts nitric a cid, and 2.3'partshydrochloric acid?-1% mills No. 22 inhibitor was added, the remainder being water. The polish obtained was equally as good as in the previous example.
Excellent results have been achieved while using the new baths for the removal of scale and the chemical polishing of stainless steel generally. Particularly good results have been achieved in polishing Nos. 302, 304, 308 and 321 stainless steels. No. 302 consists of 17-19% chromium. 8-10% nickel, ODS-0.15% carbon and the remainder iron. No. 304 stainless steel consists of 18-20% chromium, 8-11% nickel, a maximum of. 0.08% carbon, 2% manganese and the remainder iron. No. 308 stainless steel consists of 19-21% chromium, 10-12% nickel, a maximum of 0.08% carbon and the remainder iron. No. 321 stainless steel consists of 17-19% chromium, 8-11% nickel, an amount of titanium that is five times the amount of carbon and the remainder iron.
Other experiments were carried out in which the Mtgaid to hydrochloric acid ratios were varied ram :1 to 1 :2, or in which the phosphoric acid was completely replaced by sulfuric acid including an inhibitor. A bright seififiniifdrsurface was obtained in all cases.
For handling and storage purposes, the phosphoric and nitric acids may be supplied in a coneentrated mixture, and then mixed with water and hydrochloric acid and an inhibitor, if any is used, to make the treating bath. This concentrated mixture preferably contains from about 60 to 75% by weight of phosphoric acid, about 8 to 12% of nitric acid, and the balance water. An excellent concentrated mixture is one containing about 65% of phosphoric acid, 9% of nitric acid and 26% of water.
The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom.
claim:
(1.. A bath for the chemical polishing of stainless steel surfaces and the removal of scale therefrom, consisting essentially of an aqueous solution having a total acid concentration between 20 and 35% by weight and including nitric acid, hydrochloric acid, and between about 15 to 25% by weight of the total solution of an acid of the class consisting of phosphoric acid, sulfp rigacid, and a mixture of phosphoric and sulfuric acids, at least 2% of the total solution being acid and at least 2% being hydrochloric acid, with the combined weight of the nitric and hydrochloric acids being not more than the total weight of said class.
2. The bath of claim 1 wherein said member of said class is phosphoric acid.
3. The bath of claim 1 wherein said member of said class is a mixture of phosphoric and sulfuric acids.
The bath of claim 1 wherein said member of said class is sulfuric acid.
5. The bath of claim 1 wherein said bath includes an organic inhibitor.
6. A bath for the chemical polishing of stainless steel surfaces and the removal of scale therefrom, consisting essentially of about 15 to 25% by weight of phosphoric acid, about 2 to 6 4% of nitric acid, about 2 to 5% of hydrochloric acid, and the remainder being essentially water.
7. A composition of matter consisting of about 24% by weight of phosphoric acid, about 3% of nitric acid, about 3% of hydrochloric acid, and the remainder water.
8. The method of polishing a stainless steel surface which comprises contacting said surface with an acid solution consisting essentially of about 15 to 25% by weight of phosphoric acid, about 2 to 4% of nitric acid, about 2 to 5% of hydrochloric acid, and the remainder water for a period of time and at a temperature suflicient to remove scale and produce a bright polished surface.
9. The method of claim 8 wherein said period of time is from about 5 to 10 minutes and the temperature is at least about F.
JOHN R. SWIHAR'I'.
References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,080,348 Truitt May 11, 1937 2,166,990 Gray July 25, 1939 2,194,498 Dupernell Mar. 26, 1940 2,334,699 Faust Nov. 23, 1943 2,337,062 Page Dec. 21, 1943 2,348,359 Pray May 1, 1944 2,411,532 Escofiery Nov. 26, 1946 2,428,464 Lum Oct. 7, 1947 2,434,021 Thompson Jan. 6, 1948 2,446,060 Pray et a1 July 27, 1948 2,461,228 Miles Feb. 8, 1949 2,521,580 Hornak Sept. 5, 1950 OTHER REFERENCES Monypenny, Stainless Iron and Steel, London Chapman and Hall Publication, Cpw. 1931, pages 495 and 493.
Monypenny (Volume 1), Cpw. 1951, pages 180- 183.
Claims (1)
1. A BATH FOR THE CHEMICAL POLISHING OF STAINLESS STEEL SURFACES AND THE REMOVAL OF SCALE THEREFROM, CONSISTING ESSENTIALLY OF AN AQUEOUS SOLUTION HAVING A TOTAL ACID CONCENTRATION BETWEEN 20 AND 35% BY WEIGHT AND INCLUDING NITRIC ACID, HYDROCHLORIC ACID, AND BETWEEN ABOUT 15 TO 25% BY WEIGHT OF THE TOTAL SOLUTION OF AN ACID OF THE CLASS CONSISTING OF PHOSPHORIC ACID, SULFURIC ACID, AND A MIXTURE OF PHOSPHORIC AND SULFURIC ACIDS, AT LEAST 2% OF THE TOTAL SOLUTION BEING NITRIC ACIDS, AND AT LEAST 2% BEING HYDROCHLORIC ACID, WITH THE COMBINED WEIGHT OF THE NITRIC AND HYDROCHLORIC ACIDS BEING NOT MORE THAN THE TOTAL WEIGHT OF SAID CLASS.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US112840A US2662814A (en) | 1949-08-27 | 1949-08-27 | Method and composition for chemically polishing metals |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US112840A US2662814A (en) | 1949-08-27 | 1949-08-27 | Method and composition for chemically polishing metals |
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| Publication Number | Publication Date |
|---|---|
| US2662814A true US2662814A (en) | 1953-12-15 |
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| US112840A Expired - Lifetime US2662814A (en) | 1949-08-27 | 1949-08-27 | Method and composition for chemically polishing metals |
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Cited By (30)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2762728A (en) * | 1953-10-02 | 1956-09-11 | Lyon Inc | Steel pickling process |
| US2890944A (en) * | 1956-05-25 | 1959-06-16 | North American Aviation Inc | Continuous chemical milling process |
| US2981610A (en) * | 1957-05-14 | 1961-04-25 | Boeing Co | Chemical milling process and composition |
| US3125475A (en) * | 1964-03-17 | Method of producing a bright finish | ||
| US3203884A (en) * | 1959-11-20 | 1965-08-31 | Siemens Ag | Bath and method for anodic brightening of metals |
| US3275560A (en) * | 1962-05-23 | 1966-09-27 | Eutectic Welding Alloys | Metal cleaning paste |
| US3457107A (en) * | 1965-07-20 | 1969-07-22 | Diversey Corp | Method and composition for chemically polishing metals |
| US3463733A (en) * | 1964-08-22 | 1969-08-26 | Fmc Corp | Process for etching printed circuits |
| US3635826A (en) * | 1969-11-03 | 1972-01-18 | Amchem Prod | Compositions and methods for treating metal surfaces |
| US3645790A (en) * | 1969-02-17 | 1972-02-29 | Hooker Chemical Corp | Composition and process for cleaning metal |
| US3673094A (en) * | 1969-07-07 | 1972-06-27 | Armco Steel Corp | Chemical milling method and bath for steel |
| FR2208006A1 (en) * | 1972-11-24 | 1974-06-21 | Produits Ind Cie Fse | De-passivation of stainless steel - prior to plating or coating with copper, nickel, chromium, zinc, manganese, oxalate or phosphate |
| EP0019964A1 (en) * | 1979-05-25 | 1980-12-10 | SOLVAY & Cie (Société Anonyme) | Bath for the chemical polishing of steel surfaces |
| FR2463820A1 (en) * | 1979-08-24 | 1981-02-27 | Diversey Corp | Bath for polishing stainless steel - and low expansion alloys, comprises aq. soln. of acids, surfactant and thiourea deriv. |
| US4435223A (en) | 1981-06-24 | 1984-03-06 | Amchem Products, Inc. | Non-fluoride acid compositions for cleaning aluminum surfaces |
| US4460479A (en) * | 1978-09-14 | 1984-07-17 | Mulder Gerard W | Method for polishing, deburring and descaling stainless steel |
| US4569779A (en) * | 1985-01-03 | 1986-02-11 | Jabalee Walter J | Solution for cleansing a cooling system |
| US4652340A (en) * | 1985-03-04 | 1987-03-24 | Solvay & Cie (Societe Anonyme) | Baths and process for the chemical polishing of steel surfaces |
| US4678541A (en) * | 1985-06-03 | 1987-07-07 | Solvay & Cie. (Societe Anonyme) | Baths and process for chemical polishing of stainless steel surfaces |
| US4707191A (en) * | 1984-03-09 | 1987-11-17 | Societe Nationale D'etude Et De Construction De Moteurs D'aviation (Snecma) | Pickling process for heat-resistant alloy articles |
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| CN103046053A (en) * | 2012-09-21 | 2013-04-17 | 中国兵器工业第二一三研究所 | Chemical polishing method of stainless steel by high-temperature oxidation |
| CN103757636A (en) * | 2014-01-07 | 2014-04-30 | 华南理工大学 | Chemical polishing solution and alloy surface polishing treatment method |
| US8877084B2 (en) * | 2012-06-22 | 2014-11-04 | General Electric Company | Method for refreshing an acid bath solution |
| EP3878579A1 (en) * | 2020-03-09 | 2021-09-15 | Acondicionamiento Tarrasense | Procedure for finishing stainless steel parts |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3125475A (en) * | 1964-03-17 | Method of producing a bright finish | ||
| US2762728A (en) * | 1953-10-02 | 1956-09-11 | Lyon Inc | Steel pickling process |
| US2890944A (en) * | 1956-05-25 | 1959-06-16 | North American Aviation Inc | Continuous chemical milling process |
| US2981610A (en) * | 1957-05-14 | 1961-04-25 | Boeing Co | Chemical milling process and composition |
| US3203884A (en) * | 1959-11-20 | 1965-08-31 | Siemens Ag | Bath and method for anodic brightening of metals |
| US3275560A (en) * | 1962-05-23 | 1966-09-27 | Eutectic Welding Alloys | Metal cleaning paste |
| US3463733A (en) * | 1964-08-22 | 1969-08-26 | Fmc Corp | Process for etching printed circuits |
| US3457107A (en) * | 1965-07-20 | 1969-07-22 | Diversey Corp | Method and composition for chemically polishing metals |
| US3645790A (en) * | 1969-02-17 | 1972-02-29 | Hooker Chemical Corp | Composition and process for cleaning metal |
| US3673094A (en) * | 1969-07-07 | 1972-06-27 | Armco Steel Corp | Chemical milling method and bath for steel |
| US3635826A (en) * | 1969-11-03 | 1972-01-18 | Amchem Prod | Compositions and methods for treating metal surfaces |
| FR2208006A1 (en) * | 1972-11-24 | 1974-06-21 | Produits Ind Cie Fse | De-passivation of stainless steel - prior to plating or coating with copper, nickel, chromium, zinc, manganese, oxalate or phosphate |
| US4460479A (en) * | 1978-09-14 | 1984-07-17 | Mulder Gerard W | Method for polishing, deburring and descaling stainless steel |
| EP0019964A1 (en) * | 1979-05-25 | 1980-12-10 | SOLVAY & Cie (Société Anonyme) | Bath for the chemical polishing of steel surfaces |
| FR2457315A1 (en) * | 1979-05-25 | 1980-12-19 | Solvay | BATH FOR CHEMICAL POLISHING OF STEEL SURFACES |
| FR2463820A1 (en) * | 1979-08-24 | 1981-02-27 | Diversey Corp | Bath for polishing stainless steel - and low expansion alloys, comprises aq. soln. of acids, surfactant and thiourea deriv. |
| US4435223A (en) | 1981-06-24 | 1984-03-06 | Amchem Products, Inc. | Non-fluoride acid compositions for cleaning aluminum surfaces |
| US4707191A (en) * | 1984-03-09 | 1987-11-17 | Societe Nationale D'etude Et De Construction De Moteurs D'aviation (Snecma) | Pickling process for heat-resistant alloy articles |
| US4569779A (en) * | 1985-01-03 | 1986-02-11 | Jabalee Walter J | Solution for cleansing a cooling system |
| WO1986004051A1 (en) * | 1985-01-03 | 1986-07-17 | Jabalee Walter J | Solution for cleansing a cooling system |
| US4652340A (en) * | 1985-03-04 | 1987-03-24 | Solvay & Cie (Societe Anonyme) | Baths and process for the chemical polishing of steel surfaces |
| US4678541A (en) * | 1985-06-03 | 1987-07-07 | Solvay & Cie. (Societe Anonyme) | Baths and process for chemical polishing of stainless steel surfaces |
| US5135610A (en) * | 1986-12-15 | 1992-08-04 | Solvay & Cie | Baths and process for chemical polishing of stainless steel surfaces |
| EP0425013A1 (en) * | 1989-10-26 | 1991-05-02 | SOLVAY (Société Anonyme) | Baths and process for chemical polishing of stainless steel surfaces |
| BE1003579A3 (en) * | 1989-10-26 | 1992-04-28 | Solvay | Baths and method for chemically polishing steel surfaces inxoydable. |
| US5209820A (en) * | 1990-06-19 | 1993-05-11 | Solvay & Cie (Societe Anonyme) | Baths and process for the chemical polishing of stainless steel surfaces |
| US5279707A (en) * | 1992-10-23 | 1994-01-18 | Time Savers | Die discoloration remover solution and method |
| FR2717829A1 (en) * | 1994-03-28 | 1995-09-29 | Solvay | Baths and process for the chemical polishing of stainless steel surfaces. |
| WO1995026428A1 (en) * | 1994-03-28 | 1995-10-05 | Solvay S.A. | Baths and method for chemically polishing stainless steel surfaces |
| US5762819A (en) * | 1994-03-28 | 1998-06-09 | Solvay (Societe Anonyme) | Baths and process for chemical polishing of stainless steel surfaces |
| US20040152614A1 (en) * | 2003-01-23 | 2004-08-05 | Henkel Kommanditgesellschaft Auf Aktien (Henkel Kgaa) | Cleaner composition for formed metal articles |
| US8216992B2 (en) | 2003-01-23 | 2012-07-10 | Henkel Kgaa | Cleaner composition for formed metal articles |
| US9447507B2 (en) | 2003-01-23 | 2016-09-20 | Henkel Ag & Co. Kgaa | Cleaner composition for formed metal articles |
| US8877084B2 (en) * | 2012-06-22 | 2014-11-04 | General Electric Company | Method for refreshing an acid bath solution |
| CN103046053A (en) * | 2012-09-21 | 2013-04-17 | 中国兵器工业第二一三研究所 | Chemical polishing method of stainless steel by high-temperature oxidation |
| CN103046053B (en) * | 2012-09-21 | 2015-04-01 | 中国兵器工业第二一三研究所 | Chemical polishing method of stainless steel by high-temperature oxidation |
| CN103757636A (en) * | 2014-01-07 | 2014-04-30 | 华南理工大学 | Chemical polishing solution and alloy surface polishing treatment method |
| CN103757636B (en) * | 2014-01-07 | 2016-06-22 | 华南理工大学 | A kind of chemical polishing solution and alloy surface polishing method |
| EP3878579A1 (en) * | 2020-03-09 | 2021-09-15 | Acondicionamiento Tarrasense | Procedure for finishing stainless steel parts |
| WO2021180480A1 (en) | 2020-03-09 | 2021-09-16 | Acondicionamiento Tarrasense | Procedure for finishing stainless steel parts |
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