US2951768A - Chemical removal of zinc coating from iron - Google Patents
Chemical removal of zinc coating from iron Download PDFInfo
- Publication number
- US2951768A US2951768A US614991A US61499156A US2951768A US 2951768 A US2951768 A US 2951768A US 614991 A US614991 A US 614991A US 61499156 A US61499156 A US 61499156A US 2951768 A US2951768 A US 2951768A
- Authority
- US
- United States
- Prior art keywords
- zinc
- steel
- hydrochloric acid
- local area
- removal
- 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
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 title claims description 32
- 229910052725 zinc Inorganic materials 0.000 title claims description 32
- 239000011701 zinc Substances 0.000 title claims description 32
- 238000000576 coating method Methods 0.000 title claims description 10
- 239000011248 coating agent Substances 0.000 title claims description 9
- 239000000126 substance Substances 0.000 title description 8
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title description 4
- 229910052742 iron Inorganic materials 0.000 title description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 37
- ORTQZVOHEJQUHG-UHFFFAOYSA-L copper(II) chloride Chemical compound Cl[Cu]Cl ORTQZVOHEJQUHG-UHFFFAOYSA-L 0.000 claims description 18
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 16
- 229910000831 Steel Inorganic materials 0.000 claims description 15
- 239000010959 steel Substances 0.000 claims description 15
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 13
- 229910052802 copper Inorganic materials 0.000 claims description 13
- 239000010949 copper Substances 0.000 claims description 13
- 238000000034 method Methods 0.000 claims description 10
- 229910001335 Galvanized steel Inorganic materials 0.000 claims description 7
- 229960003280 cupric chloride Drugs 0.000 claims description 7
- 239000008397 galvanized steel Substances 0.000 claims description 7
- 230000001464 adherent effect Effects 0.000 claims description 3
- 230000006378 damage Effects 0.000 claims description 3
- 208000027418 Wounds and injury Diseases 0.000 claims description 2
- 208000014674 injury Diseases 0.000 claims description 2
- 239000000243 solution Substances 0.000 description 15
- 238000006243 chemical reaction Methods 0.000 description 8
- 239000000203 mixture Substances 0.000 description 7
- 239000002253 acid Substances 0.000 description 5
- 238000003466 welding Methods 0.000 description 4
- 238000007747 plating Methods 0.000 description 3
- 239000012047 saturated solution Substances 0.000 description 3
- 230000002939 deleterious effect Effects 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 230000001680 brushing effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 239000003112 inhibitor Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000005507 spraying Methods 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
- C23F1/00—Etching metallic material by chemical means
- C23F1/44—Compositions for etching metallic material from a metallic material substrate of different composition
-
- 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
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
- C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
- C23C18/31—Coating with metals
- C23C18/38—Coating with copper
Definitions
- the present invention concerns a chemical composition and method of using same and in particular concerns a chemical composition and method for removing zinc from galvanized steel.
- An object of this invention is to provide a chemical composition and method of using same.
- Another object is to provide a chemical composition and method to remove zinc from galvanized steel.
- Another object is to provide a chemical composition and method to remove zinc from galvanized steel so that the zinc is completely removed but the steel surface is not attacked.
- the present invention encompasses the use of a water solution of cupric chloride and hydrochloric acid which is applied to the galvanized area of steel that is to be cleaned.
- the fol-lowing examples of the composition are illustrative Example I 2 pints water 4 pints hydrochloric acid (30% HCl in water) 40 oz. copper chloride
- the 2 pints of water and 4 pints of hydrochloric acid form about a 20% solution of HCl in water.
- Example II 3 pints water 3 pints hydrochloric acid 40 oz. copper chloride
- the 3 pints of water and 3 pints of hydrochloric acid form about a 15% solution of HCl in water.
- Example III 2 /2 pints water 4 pints hydrochloric acid 24 oz. copper chloride The 2 /2 pints of water and 4 pints of hydrochloric acid form about a 17% solution of HCl in water.
- cupric chloride and hydrochloric acid are critical and when used in the critical proportions we have discovered, there are produced results that differ unexpectedly from the teachings of the prior art.
- cupric chloride When less than our critical proportion of cupric chloride is used there is an unsatisfactory removal of zinc and plating of copper. Although the reasons are not entirely clear it may be due to faulty removal of the zinc, to faulty deposit of copper, or it may result from unsatisfactory evolution of hydrogen bubbles which interfere with the zinc removal and copper plating.
- hydrochloric acid should not be less than about 15% in the water solution and should not be more than about 20% in water solution. In solutions within such range we have found that sufficient copper chloride must be used to form at least about a 50% saturated solution and as high as a saturated solution.
- the solution may be applied locally in various ways such as brushing, spraying, pouring, and by the spout of an oil can.
- a single application of our solution may be sufficient to remove the zinc.
- several applications of our solution can be successively app-lied.
- the method of preparing a local area of the surface of zinc galvanized steel for welding by removal of the zinc coating from the local area only where the weld is to be made, without injury to the underlying steel comprises maintaining solely on such local area a water solution containingb'etween about 15% and about 20% hydrochloric acid and cupric chloride in more than ap-' lying steel, which comprises maintaining solely on'such 10 local area, a water solution of hydrochloric acid and cupric chloride in which the acid is between about .15 and 20% of the solution and the cupric chloride is sufli cient to form between a 50% and a 100% saturated solution, for a period of time until all of the adherent zinc on such local area is replaced with metallic copper from said solution, whereby as rapidly as the zinc of said coating is removed it is replaced by a coating of metallic copper that prevents damage to the underlying steel by the hydrochloric acid of the solution.
Landscapes
- Chemical & Material Sciences (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Coating With Molten Metal (AREA)
Description
2,951,768 Patented Sept. 6, 1960 CHEMICAL REMOVAL OF ZINC COATING FROM IRON Mark P. Brash, 762 Granite St., Braintree, Mass.; Ed-
mund F. Coleman, 29 Armandine St., Dorchester, ass.; and John F. McMann, 668 Sea St., Quincy,
No Drawing. Filed Oct. 9, 1956, Ser. No. 614,991 2 Claims. (Cl. 117- 37) (Granted under Title 35, US. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.
The present invention concerns a chemical composition and method of using same and in particular concerns a chemical composition and method for removing zinc from galvanized steel.
In welding steel plates it is necessary that the area to be welded is clean and free from deleterious foreign material so that a weld of integrity can be formed.
Thus in welding steel plates that have been previously galvanized it is necessary to remove the zinc from the weld area and expose a totally zinc-free surface before welding is begun. The conventional method of removing such zinc is by grinding the weld area with a pneumatic grinding machine. This method of removal is unsatisfactory because it mechanically abrades and gouges the steel surface as the zinc is removed so that there results a defective weld area.
In the past chemical removal of zinc from galvanized steel was by means of acid which not only removed the zinc but attacked the steel surface. Various attempts were made to add inhibitors to the acid to slow down the reaction so that an operator could visually detect the critical moment when zinc removal was completed and before acid attack on the steel started and so stop the reaction at this moment. This method has always been unsatisfactory because human error results in the reaction being stopped either before complete removal of the .zinc or after acid attack of the steel had begun.
Our method has eliminated this difficulty by providing an exchange reaction whereby the zinc is completely removed from the steel and automatically upon completion of such removal there is deposited a copper coating which stops the reaction. Use of the hydrochloric acid modifies the exchange reaction so that there is insured a smooth, rapid and complete removal of zinc together with a thin copper coating of optimum texture.
An object of this invention is to provide a chemical composition and method of using same.
Another object is to provide a chemical composition and method to remove zinc from galvanized steel.
Another object is to provide a chemical composition and method to remove zinc from galvanized steel so that the zinc is completely removed but the steel surface is not attacked.
Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description of examples of the composition.
The present invention encompasses the use of a water solution of cupric chloride and hydrochloric acid which is applied to the galvanized area of steel that is to be cleaned. The fol-lowing examples of the composition are illustrative Example I 2 pints water 4 pints hydrochloric acid (30% HCl in water) 40 oz. copper chloride The 2 pints of water and 4 pints of hydrochloric acid form about a 20% solution of HCl in water.
Example II 3 pints water 3 pints hydrochloric acid 40 oz. copper chloride The 3 pints of water and 3 pints of hydrochloric acid form about a 15% solution of HCl in water.
Example III 2 /2 pints water 4 pints hydrochloric acid 24 oz. copper chloride The 2 /2 pints of water and 4 pints of hydrochloric acid form about a 17% solution of HCl in water.
The proportions of cupric chloride and hydrochloric acid are critical and when used in the critical proportions we have discovered, there are produced results that differ unexpectedly from the teachings of the prior art.
When less than my critical lower limit of hydrochloric acid is used, the zinc removal is unsatisfactory. Although the reasons are not entirely clear it may be that the exchange reaction of copper and zinc is such that there is: deleterious precipitation of copper. However, when the proportion of hydrochloric acid is above my lower criti-- cal limit, there is a uniform removal of zinc from all areas of the galvanized steel until when the last zinc is: removed a smooth deposit of copper is formed in the steel. Furthermore, when less than my critical lower limit of hydrochloric acid is used, the copper does not deposit in a satisfactory plating in exchange with the zinc. However, when the proportion of hydrochloric acid is above my lower critical limit, there is a smooth exchange reaction and a smooth coating of copper deposits on the steel to furnish a superior weld area.
When less than our critical proportion of cupric chloride is used there is an unsatisfactory removal of zinc and plating of copper. Although the reasons are not entirely clear it may be due to faulty removal of the zinc, to faulty deposit of copper, or it may result from unsatisfactory evolution of hydrogen bubbles which interfere with the zinc removal and copper plating.
We have found that the hydrochloric acid should not be less than about 15% in the water solution and should not be more than about 20% in water solution. In solutions within such range we have found that sufficient copper chloride must be used to form at least about a 50% saturated solution and as high as a saturated solution. I
The solution may be applied locally in various ways such as brushing, spraying, pouring, and by the spout of an oil can. For light galvanized coatings a single application of our solution may be sufficient to remove the zinc. For thicker layers of zinc, several applications of our solution can be successively app-lied.
Obviously many modifications and variations ,of the present invention are possible in the light of the above teachings. It is therefore 0t be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.
We claim:
1. The method of preparing a local area of the surface of zinc galvanized steel for welding by removal of the zinc coating from the local area only where the weld is to be made, without injury to the underlying steel which comprises maintaining solely on such local area a water solution containingb'etween about 15% and about 20% hydrochloric acid and cupric chloride in more than ap-' lying steel, which comprises maintaining solely on'such 10 local area, a water solution of hydrochloric acid and cupric chloride in which the acid is between about .15 and 20% of the solution and the cupric chloride is sufli cient to form between a 50% and a 100% saturated solution, for a period of time until all of the adherent zinc on such local area is replaced with metallic copper from said solution, whereby as rapidly as the zinc of said coating is removed it is replaced by a coating of metallic copper that prevents damage to the underlying steel by the hydrochloric acid of the solution.
References Cited in the file of this patent UNITED STATES PATENTS 548,039 Coyle Oct. 15, 1895 2,217,921 Saukaitis Oct. 15, 1940 2,410,844
Signaigo et al Nov. 12, 1946
Claims (1)
1. THE METHOD OF PREPARING A LOCAL AREA OF THE SURFACE OF ZINC GALVANIZED STEEL FOR WELDING BY REMOVAL OF THE ZINC COATING FROM THE LOCAL AREA ONLY WHERE THE WELD IS TO BE MADE, WITHOUT INJURY TO THE UNDERLYING STEEL WHICH COMPRISES MAINTAINING SOLELY ON SUCH LOCAL AREA A WATER SOLUTION CONTAINING BETWEEN ABOUT 15% AND ABOUT 20% HYDROCHLORIC ACID AND CUPRIC CHLORIDE IN MORE THAN APPROXIMATELY HALF OF THAT NECESSARY TO SATURATE THE SOLUTION, FOR A PERIOD OF TIME UNTIL THE ADHERENT ZINC ON THE STEEL IN SUCH LOCAL AREA IS REPLACED BY ADHERENT METALLIC COPPER.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US614991A US2951768A (en) | 1956-10-09 | 1956-10-09 | Chemical removal of zinc coating from iron |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US614991A US2951768A (en) | 1956-10-09 | 1956-10-09 | Chemical removal of zinc coating from iron |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2951768A true US2951768A (en) | 1960-09-06 |
Family
ID=24463549
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US614991A Expired - Lifetime US2951768A (en) | 1956-10-09 | 1956-10-09 | Chemical removal of zinc coating from iron |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US2951768A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3201211A (en) * | 1962-06-22 | 1965-08-17 | Allegheny Ludlum Steel | Stainless steel trim member |
| US3395040A (en) * | 1965-01-06 | 1968-07-30 | Texas Instruments Inc | Process for fabricating cryogenic devices |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US548039A (en) * | 1895-10-15 | Process of treating sheet-iron | ||
| US2217921A (en) * | 1938-03-23 | 1940-10-15 | American Chem Paint Co | Art of drawing ferrous metal |
| US2410844A (en) * | 1942-01-14 | 1946-11-12 | Du Pont | Metal plating process |
-
1956
- 1956-10-09 US US614991A patent/US2951768A/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US548039A (en) * | 1895-10-15 | Process of treating sheet-iron | ||
| US2217921A (en) * | 1938-03-23 | 1940-10-15 | American Chem Paint Co | Art of drawing ferrous metal |
| US2410844A (en) * | 1942-01-14 | 1946-11-12 | Du Pont | Metal plating process |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3201211A (en) * | 1962-06-22 | 1965-08-17 | Allegheny Ludlum Steel | Stainless steel trim member |
| US3395040A (en) * | 1965-01-06 | 1968-07-30 | Texas Instruments Inc | Process for fabricating cryogenic devices |
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