US2607722A - Electrolytic polishing of stainless steel - Google Patents

Electrolytic polishing of stainless steel Download PDF

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Publication number
US2607722A
US2607722A US724912A US72491247A US2607722A US 2607722 A US2607722 A US 2607722A US 724912 A US724912 A US 724912A US 72491247 A US72491247 A US 72491247A US 2607722 A US2607722 A US 2607722A
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United States
Prior art keywords
polishing
stainless steel
electrolyte
water
acid
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Expired - Lifetime
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US724912A
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English (en)
Inventor
John F Kreml
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Armco Inc
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Armco Inc
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Publication date
Priority to BE476971D priority Critical patent/BE476971A/xx
Application filed by Armco Inc filed Critical Armco Inc
Priority to US724912A priority patent/US2607722A/en
Priority to CH274534D priority patent/CH274534A/fr
Application granted granted Critical
Publication of US2607722A publication Critical patent/US2607722A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
    • C25F3/00—Electrolytic etching or polishing
    • C25F3/16—Polishing
    • C25F3/22—Polishing of heavy metals
    • C25F3/24—Polishing of heavy metals of iron or steel

Definitions

  • This invention relates to the polishing of copper, molybdenum, tungsten, vanadium, cumeta1, more especially to a process and an eleclumbium, titanium, sulphur, selenium, phostrolyte for electrolytically polishing the same.
  • phorus and the'lik'e for special purposes, and a object of my invention is the provision of remainder which is substantially all iron.
  • Another object is that of providing a process
  • sa'ry amount of mechanical work for polishing is the-prowhere the metal to be polished has relatively invision of a highly efiective electrolytic polishing accessible areas by reason of'sha'pe or contour. solution which remains fluid at low tempera- Then, too, in polishing.
  • the invention accordingly consists in the comelectrolytic polishing far surpasses mechanical ination of elements, composition of materials, polishing methodsfrom the point of view of time and inthe several operations steps and the re-'- consumed during the-a'ctualpolishingoperations lation of each of the same to one or more of the and results obtained.
  • Electrolytic polishing enothers as described herein, the. scope of the 'ap- 39 ables the achievement of greater surface brilplic'ation of which is indicated in thefollowing liance and improved beauty, there being evenclaims. ness and uniformity of finish despite intricate ,In the singleview of'the accompanying'draw contours or angularities;which-may have been ing I graphically. illustrate the composition enequntered'for po1ishing, w I,
  • the eleche'steel has a dull graYaDD a G aft trolyte is opento'one or more of the objections polishing a es on a brightness which remains 5 of having low electrical-conductivity, poor throw- W h a Permanence as under conditions of ooring power which renders it diificul-t to polish rosive attack.
  • the steel actually varies in its deep-drawn, angular or other "deep-shaped obcorros'ioneresistancei and other properties a'c-' jects, a'toolow polishing rate asapplied tostaincording. to composition and treatment, but for less steel, and a lowboil-ing point leading to exe Sa e Of definition usually is recognized as cessive evaporation.
  • Many of th solutions have containing from. 0.01 to 0.25%. or substantially an exceedingly high init'al'cos re xtre'mely more carbon, and about.10% to 35%. or more expensive t mai ai chromium, these elements being-presentwith or still other pOj without nickel, and with or without. supplemental; additions ofv manganese; silicon, acobalt, 5
  • An outstanding object of my invention accordingly is the provision of a process for electrolytically polishing stainless steel, employing a polishing solution and conditions of operation which are practical and conducive to the achievement of satisfactorily polished stainless steel surfaces, which process is economical in initial cost and maintenance of the electrolyte solution employed, and which is well suited for shutdown at relatively low temperatures over extended periods of time without substantial solidification of the electrolyte.
  • the electrolyte advantageously is an aqueous solution composed of or containing, by weight, at least about 20% up to approximately '7 glycolic acid, at least about 15% up to about 55% sulphuric acid and at least about 5% up to about 30% water, these figures being predicated'upon acids in anhydrous state.
  • the composition range employed is'generally indicated by the solid line ring in the accompanying drawing.
  • the electrolyte afforded for my electro-chemical polishing process is conveniently shipped in suitable containers as a solution which is ready for direct use without need for admixing of the several ingredients by the consumer. Where desired, of course, the ingredients may be mixed or replenished at the point of use.
  • the electrolyte has the highly important characteristic of resisting solidification under usual temperature conditions of transit and at temperatures considerably below ordinary room temperatures where the application of heat for the polishing process has been discontinued in favor of resuming operations at a later time. As further characteristics, the electrolyte has high electrical conductivity, good throwing power and a sufficiently'high boiling point to enable high temperature use without excessive losses by evaporation. 7
  • I employ a suitable tank for containing the electrolyte in the stainlesssteel polishing operations, this container advantageously being lined with acid-resisting material, as for example, lead, ceramic or glass.
  • the electrolyte, which I pour into the tank preferably contains by weight about 55% glycolic acid, approximately 30% sulphuric acid, and the remainder substantially all water.
  • This solution I find is extremely valuable for achieving an electrolytically polishedsurface on the steel and, moreover, is capable of resisting solidification at temperatures even lower than about 2".
  • I immerse one or more stainless steel products in the electrolyte illustratively a low-carbon 18-8 chromium-nickel stainless steel sink strainer possessing; a cold-rolled surface having an area of about twenty-square inches and make the same the anode .iby,.connection with a suitable source ,of direct current electrical supply.
  • oneoramorerjcathodes such as of lead, copper or other electrically conductive material connected with thesource of'electrical supply.
  • the cathode area is not critical'but in order to achieve most satisfactory results I usuallyfindcit .best to have the cathodes of a size commensurate withithe bodily extent of the stainless steel to bexpolished, this for obtaining a more uniform polishing action.
  • the supply of heat for this purpose conveniently is afforded from a suitable heating coil immersed in the electrolyte or built into the tank wall.
  • My process further is amenable to electro chemically treating stainless steel objects such as wire which are continuously moved through the glycolic acid electrolyte.
  • stainless steel objects such as wire which are continuously moved through the glycolic acid electrolyte.
  • I subject 0.045 inch diameter 18-8 chromium-nickel stainless steel wire to continuous feeding through an electrolyte containing approximately 50% glycolic acid, 33% sulphuric acid and the remainder substantially all water, the operations being in a polishing tank some 10 feet in length and at a feeding speed of about 5 feet per minute longitudinally through the tank.
  • Six equally spaced copper anodes such as rollers illustratively provide contacts for the 'wire, while for example cathodes made of straight lengths ofcopper bus bar extend on opposite sides of the wire for the length of the tank.
  • I employ a current density of some 6.5 amperes per square inch of the immersed wire surface and a solution temperature of about 50 0.
  • a rinsing tank preferably adapted for recovery of dragoff of the electrolyte.
  • My electrolytic polishing process is successfully practiced on articles and products in which the stainless steel is of widely varying quality whether of the straight chromium or chromiumnickel grade, and reliably gives uniformly pol-' ished surfaces even where surfaces of intricate contour are encountered.
  • the metal under treatment possesses a hammered surface such as is often the case of ornamental trim, hardware, and objects of art including frames, bowls and urns, an even, lustrous polish nevertheless is obtained.
  • Other stainless steel surfaces encountered on grilles, trays, and the like, fabricated by the welding of wire, strip and other converted forms, also are polished successfully.
  • the polished surfaces achieved are substantially 6 free 'of pits, scratches or blemishes, and the welded portions likewise are free of burns, thus resisting corrosion and maintaining their attractiveness over a long period f time.
  • The-treatment in accordance with my invention is at times useful for such purposes as electrolytically removing thicknesses of metal, in the sense of a machining operation, for achieving desired dimensions of products as well as a smooth finish.
  • the electrolytic polishing process which I pro- .vide, moreover, is economical and capable of being carried out under operating conditions which are easy to control, or shut down as desired, as during the expeditious mass production of p01- ished stainless steel articles of outstanding surface; quality.
  • the equipment and materials needed in the process are readily available and in actual use call for-little space for the electrolytic treatment.
  • glycolic-acid, sulphuric/acid and water are highly critical constituents in the electrolyte employed in my process
  • amounts of other constituents which-do not substantially impair effectiveness of the solution also may be present, if desired.
  • ity is, readily apparent that the beneficial results of my process will be partially retained where the glycolic acid is partially replaced by some other aliphatic carboxylic acid, for example citric acid, or even an inorganic buffer, for example phosphoric acid, as employed in prior electropolishing processes.
  • an electrolytically polished stainless steel product comprising, subjecting the metal to anodic treatment in an electrolytic bath essentially consisting of 20% to glycolic acid, 10% to 60% sulphuric acid and 2% to 35% water, all figures being by weight and based upon anhydrous acids.
  • an electrolytically polished stainless steel product comprising, subjecting the metal to anodic treatment in an electrolytic bath essentially consisting of, by weight and predicated upon anhydrous acids, about 20% to 80% glycolic acid, about 10% to 60% sulphuric acid and the remainder substantially all water, this amounting to not over about 35%, while maintaining a temperature of the electrolytic bath ranging between about 25 C. and C. and a sufiiciently high current density to electrically remove metal from the surface under treatment and achieve a high polish.
  • an eelctrolytically polished stainless steel product which comprises, subjecting the steel to anodictreatment in an electrolytic bath essentially consisting of, by weight and predicatedupon anhydrous acids, about 20% to 80% glycolic acid, approximately to 60% sulphuric acid, and about 2% to 35% water, while maintaining a current density of approximately 0.2 to 10 amperes per square inch of metal surface under treatment and a temperature ofthe electrolytic bath ranging between about 25 C. and 150 C.
  • an electrolytically polished stainless steel product which comprises, subjecting the steel to treatment in an electrolytic bath by weight and predicated upon anhydrous acids consisting of approximately 55% glycolic acid, about 30% sulphuric acid, and the remainder substantially all water.
  • an electrolytically polished stainless steel product comprising, subjecting the metal to anodic treatment in an electrolytic bath by weight and predicated upon anhydrous acids essentially consisting of about 20% to70% glycolic acid, about to 55% sulphuric acid, and about 5% to 30% water, while maintaining a current density of approximately 0.5 to 1 .0 ampere per square inch of the metal surfaceundertreatment and a temperature of the electrolytic bath ranging between about 80 C. and 100 C.
  • an electrolytically polished stainless steel product which comprises, subjecting the steel to anodic treatment in an electrolytic bath by weight and predi cated upon anhydrous acids composed of approximately 55% glycolic acid, about 30% sulphuric acid and the remainder substantially all water, while maintaining a current density of approximately 0.5 to 1.0 ampere per square inch of the metal surface under treatment and a temperature of the electrolytic bath ranging between about 80 C. and 100 C.
  • An electrolyte solution of the character described essentially consisting of as the principal constituents thereof, 20% to 80% glycolic acid, 10% to sulphuric acid and remainder substantially all water up to 35%, all figures being' by weight and based upon anhydrous acids.
  • An electrolyte solution of the character described essentially consisting of, by weight and predicated upon anhydrous acids, at least about 20% but not over glycolic acid, at least about 10% but not over 60% sulphuric acid, and at least about 2% but not over 35% water.
  • An electrolyte solution having non-freezing tendencies at low temperatures and essentially consisting of, by weight and predicated upon anhydrous acids, about 20% to 70% glycolic acid and about 15% to 55% sulphuric acid, and about 5% to 30% water.
  • An electrolyte solution having non-freezing tendencies at low temperatures and essentially consisting of, by weight and predicated upon anhydrous acids, about 55% glycolic acid, approximately 30% sulphuric acid, and the remainder substantially all water.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
US724912A 1947-01-28 1947-01-28 Electrolytic polishing of stainless steel Expired - Lifetime US2607722A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
BE476971D BE476971A (US07816562-20101019-C00012.png) 1947-01-28
US724912A US2607722A (en) 1947-01-28 1947-01-28 Electrolytic polishing of stainless steel
CH274534D CH274534A (fr) 1947-01-28 1947-10-30 Procédé de traitement électrolytique des métaux.

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US724912A US2607722A (en) 1947-01-28 1947-01-28 Electrolytic polishing of stainless steel

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US2607722A true US2607722A (en) 1952-08-19

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BE (1) BE476971A (US07816562-20101019-C00012.png)
CH (1) CH274534A (US07816562-20101019-C00012.png)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2773821A (en) * 1956-06-12 1956-12-11 Electro Gleam Inc Composition for use in electropolishing
US2994664A (en) * 1958-02-19 1961-08-01 Nalco Chemical Co Dry acid cleaning compositions
US3019194A (en) * 1957-02-18 1962-01-30 Alan D Brite Cleaning composition and method
US3041285A (en) * 1955-05-27 1962-06-26 Purex Corp Ltd Composition for cleaning and polishing aluminum and aluminum alloys
US3054737A (en) * 1958-08-07 1962-09-18 British Iron Steel Research Process and bath for electrosmoothing ferrous metals
US4935112A (en) * 1988-04-07 1990-06-19 Seneca Wire And Manufacturing Company Continuous steel strand electrolytic processing
US5087342A (en) * 1988-04-07 1992-02-11 Seneca Wire And Manufacturing Company Continuous steel strand electrolytic processing
FR2747399A1 (fr) * 1996-04-12 1997-10-17 Commissariat Energie Atomique Electrolyte pour l'electropolissage, procede d'electropolissage d'un acier inoxydable ou d'un alliage de nickel mettant en oeuvre cet electrolyte, et son application a la decontamination

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2335354A (en) * 1939-02-06 1943-11-30 Rustless Iron & Steel Corp Polishing stainless iron and steel
US2382865A (en) * 1942-04-10 1945-08-14 Du Pont Bright dip

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2335354A (en) * 1939-02-06 1943-11-30 Rustless Iron & Steel Corp Polishing stainless iron and steel
US2382865A (en) * 1942-04-10 1945-08-14 Du Pont Bright dip

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3041285A (en) * 1955-05-27 1962-06-26 Purex Corp Ltd Composition for cleaning and polishing aluminum and aluminum alloys
US2773821A (en) * 1956-06-12 1956-12-11 Electro Gleam Inc Composition for use in electropolishing
US3019194A (en) * 1957-02-18 1962-01-30 Alan D Brite Cleaning composition and method
US2994664A (en) * 1958-02-19 1961-08-01 Nalco Chemical Co Dry acid cleaning compositions
US3054737A (en) * 1958-08-07 1962-09-18 British Iron Steel Research Process and bath for electrosmoothing ferrous metals
US4935112A (en) * 1988-04-07 1990-06-19 Seneca Wire And Manufacturing Company Continuous steel strand electrolytic processing
US5087342A (en) * 1988-04-07 1992-02-11 Seneca Wire And Manufacturing Company Continuous steel strand electrolytic processing
FR2747399A1 (fr) * 1996-04-12 1997-10-17 Commissariat Energie Atomique Electrolyte pour l'electropolissage, procede d'electropolissage d'un acier inoxydable ou d'un alliage de nickel mettant en oeuvre cet electrolyte, et son application a la decontamination
WO1997039168A1 (fr) * 1996-04-12 1997-10-23 Commissariat A L'energie Atomique Electrolyte pour l'electropolissage, procede d'electropolissage d'un acier inoxydable ou d'un alliage de nickel mettant en oeuvre cet electrolyte, et son application a la decontamination

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Publication number Publication date
BE476971A (US07816562-20101019-C00012.png)
CH274534A (fr) 1951-04-15

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