US1859736A - Method of cleaning metal articles - Google Patents

Method of cleaning metal articles Download PDF

Info

Publication number
US1859736A
US1859736A US372222A US37222229A US1859736A US 1859736 A US1859736 A US 1859736A US 372222 A US372222 A US 372222A US 37222229 A US37222229 A US 37222229A US 1859736 A US1859736 A US 1859736A
Authority
US
United States
Prior art keywords
acid
scale
metal
grams per
per liter
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
Application number
US372222A
Inventor
Harry S George
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ELECTRO METALLURG CO
ELECTRO METALLURGICAL Co
Original Assignee
ELECTRO METALLURG CO
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by ELECTRO METALLURG CO filed Critical ELECTRO METALLURG CO
Priority to US372222A priority Critical patent/US1859736A/en
Application granted granted Critical
Publication of US1859736A publication Critical patent/US1859736A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • CCHEMISTRY; METALLURGY
    • C23COATING 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
    • C23GCLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G1/00Cleaning or pickling metallic material with solutions or molten salts
    • C23G1/02Cleaning or pickling metallic material with solutions or molten salts with acid solutions
    • C23G1/08Iron or steel
    • C23G1/085Iron or steel solutions containing HNO3

Definitions

  • the method is especially'applicable to alloy articles consisting largely of iron and about 8% to 40% chromium.
  • Other alloy constituents may be present with the non and chromium, such as silicon, manganese, nickel, tungsten, molybdenum and the like.
  • Certain of the oxide scales on these iron and chromium alloys can be removed in acid pickling baths.
  • the acid pickling baths which have been used for this purpose remove the scales by dissolving the adhering oxide coating or by dissolving the metal underneath the scale to effect a loosening of the scale; Acid baths which will dissolve the scale also attack the metal so that with either of these methods or with a combination of them, the metal is wasted to some extent and the surface of the metal becomes etchedand roughened.
  • iron and chromium alloys are hot rolled or forged.
  • the scale that is produced by close annealing-or box annealing does not contain the rapidly'soluble oxide and it is not applicable to my process.
  • scale which is applicable to my process can be produced from a box annealed scale b chemically treating the scale in a bath whlch contains a soluble alkali, such as sodium h drox-- ide and a strong oxidizing agent, as or exan ample, chlorine.
  • Other methods of producing the scale may be used but these are among the most direct methods encountered in the ordinary fabrication of articles since the alloys are commonly subjected to at least one of as these treatments; that is hot annealing.
  • a hot rolled unannealed sheet of restless iron rolling or box containing about 18% chromium was dipped 7o? into a cleaning bath consistin of about 10 grams per liter of concentrate hydrochloric acid of 1.19 specific gravity and about 50 grains perliter of concentrated nitric acid of 1.42 specific gravity. The bath was heated :7
  • dilute acid solutions containas ing about 10 grams per liter to about 150 grams per liter of concentrated hydrochloric acid; The more concentrated of these solutions are best adapted to the alloys of higher concentrations of hydrochloric acid than 150 grams per liter deleteriously aifect the metal.
  • the preferred baths also contain at least 50 grams per liter of concentrated nitric acid.
  • nitric acid will not hinder the action of the hydrochloric acid on the scale but it will protect the metal and prevent the destructive action of hydrochloric acid.
  • concentrations of hydrochloric acid may be used which will attack the minor soluble portion of the scale ;with. great rapidity but the metal will not be attacked.
  • the method of removing coatings of oxide scale from alloy articles containing 0' ironand 8% to chromium which comprises providing a hot rolled scale on thearticle and then treating with a dilute acid solution containing not less than about 10 grams per liter of concentrated hydrochloric 5 acid and not less than about grams per liter of concentrated nitric acid, the concentration of the. solution being suflicient to dis- 7 solve only a minor readily soluble constituentf of the scale and the proportion of nitric acid' being sufiicien't to prevent solution of the metal.

Landscapes

  • 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

I HARRY S. GEORGE, OF'HAEQUA, NEW YORK, ASSIGNOR TO ELECTBQ HI'H'ALLURGICAL com, A CORPORATION OF WEST GIN'IA EETHOD 0! CL i No Drawing My invention relates to the acid picklling of alloy articles containing ironand ChIOIIllum whereby the articles'may be produced with unetched surfaces which are free from surface oxides. I
The method is especially'applicable to alloy articles consisting largely of iron and about 8% to 40% chromium. Other alloy constituents may be present with the non and chromium, such as silicon, manganese, nickel, tungsten, molybdenum and the like. Certain of the oxide scales on these iron and chromium alloys can be removed in acid pickling baths., The acid pickling baths which have been used for this purpose remove the scales by dissolving the adhering oxide coating or by dissolving the metal underneath the scale to effect a loosening of the scale; Acid baths which will dissolve the scale also attack the metal so that with either of these methods or with a combination of them, the metal is wasted to some extent and the surface of the metal becomes etchedand roughened. Sulphuric and hydrochloric acids in various concentrations have been used for this purpose but the best practice with such baths has not produced clean metal which is free from acid attack. Such a solvent action results in defective metal surfaces, high costs for pickling acids and a considerable waste of metal.
I have found that certain scales on these alloys may be removed by a new method of pickling which consists in treating with a bath which dissolves only a part of the substance of the oxide coating, This causes the remainder of the adherent coating to break away from the metal and fall off bodily. It is necessary in my process to provide an oxidized coating which contains at least one oxide constituent that is rgadilysoluble in one acid component of the bath, such as hydrochloric acid. This oxide constituent is usually a small proportion of'the scale and it is rapidly soluble in the acid, but the remainder of the oxidized coating is either insoluble oris only very slowly soluble. A scale containing rapidly soluble and practically'insoluble oxides is produced when the above chromium content.
If G METAL ARTICLES Application filed June 19, 1929. Serial No. 372,222.
named iron and chromium alloys are hot rolled or forged. The scale that is produced by close annealing-or box annealing does not contain the rapidly'soluble oxide and it is not applicable to my process. scale which is applicable to my process can be produced from a box annealed scale b chemically treating the scale in a bath whlch contains a soluble alkali, such as sodium h drox-- ide and a strong oxidizing agent, as or exan ample, chlorine. Other methods of producing the scale may be used but these are among the most direct methods encountered in the ordinary fabrication of articles since the alloys are commonly subjected to at least one of as these treatments; that is hot annealing.
As a specific illustration of my invention, a hot rolled unannealed sheet of restless iron rolling or box containing about 18% chromium was dipped 7o? into a cleaning bath consistin of about 10 grams per liter of concentrate hydrochloric acid of 1.19 specific gravity and about 50 grains perliter of concentrated nitric acid of 1.42 specific gravity. The bath was heated :7
to about C. In less than two minutes a: small amount of brownish solution was formed and the rest o-f'the oxidecoating disintegrated into small flakes which quickly disengaged themselves from-the surface of so the metal without dissolving. The oxide free metal was washed in cold water and it was found to be perfectly clean and free from acid attack.
I have used dilute acid solutions containas ing about 10 grams per liter to about 150 grams per liter of concentrated hydrochloric acid; The more concentrated of these solutions are best adapted to the alloys of higher concentrations of hydrochloric acid than 150 grams per liter deleteriously aifect the metal. The preferred baths also contain at least 50 grams per liter of concentrated nitric acid.
With the higher concentrations of hydro- 9a chloric acid, more than 50 grams per liter of nitric acid is beneficial.
With nitric acid present an excellent protective action and a brightening of. the metal is obtained. Cold acid baths may be used or they may be heated However, a. 55
Substantially higher at to any temperature up to the boiling point of the bath. The mixtures of dilute nitric and hydrochloric acids do not produce active amounts of nascent chlorine and no dissolution of the metal or scale occurs as when more concentrated acidbaths are used and nascent chlorine is present.
The resence of nitric acid will not hinder the action of the hydrochloric acid on the scale but it will protect the metal and prevent the destructive action of hydrochloric acid. With nitric acid present, concentrations of hydrochloric acid may be used which will attack the minor soluble portion of the scale ;with. great rapidity but the metal will not be attacked.
The soluble portion of the above described scale is rapidly attacked or affected by the action of the bath. This causes the scaleto )loosen or slough from the metal. Under the best conditions, a small amount of brownish solution is formed and then the main body of the scale sloughs off and falls from the surface of the metal.
i vAlthough I have described my invention with reference to a bath'consisting of solu tions of nitric and hydrochloric acids, it is evident that it is within the scope of my invention to use a bath produced with one of the acids and a salt of the other acid or with a mixture of nitrate and chloride salts with an acid. Other modifications of my invention may be made without departing therefrom, and I wish to be limited only by the prior art and by the invention as defined in the annexed claims.
I claim as my invention: 7
. 1. The method of removing coatings of oxide scale from alloy articles containing 0' ironand 8% to chromium which comprises providing a hot rolled scale on thearticle and then treating with a dilute acid solution containing not less than about 10 grams per liter of concentrated hydrochloric 5 acid and not less than about grams per liter of concentrated nitric acid, the concentration of the. solution being suflicient to dis- 7 solve only a minor readily soluble constituentf of the scale and the proportion of nitric acid' being sufiicien't to prevent solution of the metal.
2. The method of removing coatings of hot rolled. scale from alloy articles that consist largely of iron and chromium which comprises pickling in a solution containing about 10 grams per liter of concentrated'hydrochloric acid and about 50 grams per liter of concentrated nitric acid at about C.
a In testimony whereof, I aflix my i%1ature.
HARRY s. GEO GE.
US372222A 1929-06-19 1929-06-19 Method of cleaning metal articles Expired - Lifetime US1859736A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US372222A US1859736A (en) 1929-06-19 1929-06-19 Method of cleaning metal articles

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US372222A US1859736A (en) 1929-06-19 1929-06-19 Method of cleaning metal articles

Publications (1)

Publication Number Publication Date
US1859736A true US1859736A (en) 1932-05-24

Family

ID=23467213

Family Applications (1)

Application Number Title Priority Date Filing Date
US372222A Expired - Lifetime US1859736A (en) 1929-06-19 1929-06-19 Method of cleaning metal articles

Country Status (1)

Country Link
US (1) US1859736A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2915420A (en) * 1956-06-27 1959-12-01 American Can Co Nitric acid treatment of steel
US3039910A (en) * 1958-11-10 1962-06-19 Aluminum Co Of America Treating aluminum surfaces
US3048503A (en) * 1958-06-19 1962-08-07 Crucible Steel Co America Pickling apparatus and method
US3468768A (en) * 1966-07-05 1969-09-23 Bethlehem Steel Corp Surface treatment of steel electrotinning stock

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2915420A (en) * 1956-06-27 1959-12-01 American Can Co Nitric acid treatment of steel
US3048503A (en) * 1958-06-19 1962-08-07 Crucible Steel Co America Pickling apparatus and method
US3039910A (en) * 1958-11-10 1962-06-19 Aluminum Co Of America Treating aluminum surfaces
US3468768A (en) * 1966-07-05 1969-09-23 Bethlehem Steel Corp Surface treatment of steel electrotinning stock

Similar Documents

Publication Publication Date Title
US2115005A (en) Electrochemical treatment of metal
US2856275A (en) Chemical treatment of refractory metal surfaces
US2564549A (en) Pickling treatment
US3121026A (en) Descaling metals and alloys with aqueous potassium hydroxide at relatively low temperature
US1899734A (en) Removal of oxids from ferrous metal
US2876144A (en) Metal pickling solutions and methods
US3010854A (en) Pickling solution and method
US1859734A (en) Method of removing oxide coatings from metals
US2474526A (en) Picking of stainless steels
US2538702A (en) Metal surface cleaning
US1719168A (en) Pickling of metals, etc.
US1859736A (en) Method of cleaning metal articles
US2408424A (en) Pickling steels
US2643204A (en) Nitric acid pickling
US2511988A (en) Pickling process
JPS63216986A (en) High-speed pickling method for low cr steel
US2607739A (en) Cleaning worked magnesium articles
US2827402A (en) Method of pickling titanium and titanium alloys
US2418955A (en) Process of removing foreign matter from magnesium surfaces
US3595799A (en) Pickling additive
US1939241A (en) Pickling stainless steel
JPH11264087A (en) Treating liquid for descaling stainless steel and its usage
US1974570A (en) Pickling solution
US2598889A (en) Pickling chromium alloys
US2878146A (en) Method of de-oxidizing metal surfaces