EP0462646A1 - Baths and process for chemical polishing stainless steel surfaces - Google Patents

Baths and process for chemical polishing stainless steel surfaces Download PDF

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Publication number
EP0462646A1
EP0462646A1 EP91201422A EP91201422A EP0462646A1 EP 0462646 A1 EP0462646 A1 EP 0462646A1 EP 91201422 A EP91201422 A EP 91201422A EP 91201422 A EP91201422 A EP 91201422A EP 0462646 A1 EP0462646 A1 EP 0462646A1
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EP
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Prior art keywords
mole
acid
polishing
baths
acide
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German (de)
French (fr)
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EP0462646B1 (en
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Daniel Tytgat
Nathalie Barthelemy
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Solvay SA
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Solvay SA
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    • 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

  • the present invention relates to the composition of baths for the chemical polishing of stainless steel surfaces.
  • Chemical polishing of metal surfaces is a well-known technique (electrolytic and chemical polishing of metals - W.J. Mc G. TEGART - Dunod - 1960 - p. 122 et seq.); it consists of treating the metal surfaces to be polished with oxidizing baths.
  • baths are generally used comprising a mixture, in aqueous solution, of hydrochloric, phosphoric and nitric acids (patent US-A-2662814).
  • suitable additives such as surfactants, viscosity regulators and brighteners.
  • a composition of a bath for the chemical polishing of stainless steel surfaces comprising, in aqueous solution, a mixture of hydrochloric acid, nitric acid and acid.
  • phosphoric a viscosity regulator chosen from water-soluble polymers, a surfactant and sulfosalicylic acid as a brightening agent.
  • the invention aims to provide baths designed to carry out slow and effective chemical polishing of stainless steel surfaces, at working temperatures below 50 ° C.
  • the invention therefore relates to baths for the chemical polishing of stainless steel surfaces, comprising, in aqueous solution, a mixture of hydrochloric acid, nitric acid and phosphoric acid, an optionally substituted hydroxybenzoic acid and an amine. water soluble.
  • hydroxybenzoic acid serves as a brightening agent. It can be unsubstituted such as salicylic acid or substituted such as sulfosalicylic acid. Salicylic acid is preferred.
  • the amine can be selected from primary amines, secondary amines and tertiary amines. Amines are preferred, the molecule of which comprises more than 10 carbon atoms, for example between 11 and 20 carbon atoms. Primary alkylamines having 11 to 16 carbon atoms in their molecule are preferred.
  • the baths according to the invention can comprise a mixture of amines. Optimal amine content depends on the nature of the amine selected. Typically, it is between 0.001 and 1 g per liter of the aqueous solution.
  • the aqueous solution of the bath comprises, in addition to the amine, an additive selected from perchloric acid and the water-soluble salts of perchloric acid.
  • the optimum content of this additive is between 0.001 and 0.5 mole per liter of the aqueous solution.
  • the aqueous solution contains a water-soluble additive capable of breaking down nitrous acid.
  • the function of this additive is to decompose at least part of the nitrous acid which forms during the polishing of a steel surface, as a consequence of oxidation of ferrous ions released in the bath during polishing. It is preferably selected from urea and its derivatives, such as thiourea and ureines, and its optimum content is between 0.01 and 5 g per liter of the aqueous solution.
  • the baths in accordance with this embodiment of the invention are specially adapted for polishing treatments in which the ratio between the surface in contact with the bath and the volume thereof is greater than 10 m ⁇ 1.
  • the baths according to the invention are free from ferricyanide ions and ferrocyanide ions, especially when they do not contain perchloric acid.
  • the polishing baths according to the invention may optionally contain additives usually present in baths known for the chemical polishing of metals, for example surfactants, alcohols and viscosity regulators. They can in particular comprise a water-soluble abietic compound which is a chemical compound comprising an abietyl radical of general formula: or a hydroabietyl or dehydroabietyl radical.
  • the abietic compound must be soluble in the aqueous solution.
  • Abietic compounds which can be used in the baths according to the invention are abietamines.
  • abietamines which are very suitable in the baths according to the invention, are those in which at least one of the radicals X1 and X2 is a radical of general formula: -CH2-R2 wherein R2 denotes a linear or cyclic alkyl radical, substituted or unsubstituted, saturated or unsaturated, comprising at least one carbonyl group.
  • R2 denotes a linear or cyclic alkyl radical, substituted or unsubstituted, saturated or unsaturated, comprising at least one carbonyl group.
  • substituted abietamines and the means of obtaining them are described in GB-A-734665.
  • abietamines of this type which can be used in the baths according to the invention, are those in which the alkyl radical R2 is selected from acetonyl, 2-keto butyl, 4-methyl 2-keto-pentenyl-3, 4- radicals. hydroxy 4-methyl 2-keto pentyl, 2-keto cyclopentyl, 4-hydroxy 2-keto pentenyl-3, 2-keto cyclohexyl, 2,5-diketo hexyl and 2-phenyl 2-keto ethyl.
  • the baths according to the invention may also contain products of the DEHYQUART brand (Henkel), which are surfactants selected from alkylpyridinium salts and quaternary ammonium salts, comprising alkyl, phenyl or benzyl radicals, substituted or not substituted.
  • DEHYQUART brand Henkel
  • surfactants selected from alkylpyridinium salts and quaternary ammonium salts, comprising alkyl, phenyl or benzyl radicals, substituted or not substituted.
  • the baths according to the invention are suitable for polishing chemical of all surfaces in austenitic stainless steel. They are specially suitable for polishing austenitic steels containing between 16 and 26% by weight of chromium and between 6 and 22% by weight of nickel, such as steels of grades 18/8 and 18/10, optionally containing molybdenum (for example example AISI-304, 304L, 316 and 316L steels).
  • the baths according to the invention have the particularity of carrying out the polishing of such steels at slow speed, generally requiring a contact time of between 3 and 12 hours. They can be used at all temperatures between 20 ° C and the boiling temperature.
  • the baths according to the invention have the additional advantage of performing good quality polishing of welded assemblies according to the rules of the art.
  • the invention also relates to a method for polishing a stainless steel surface, according to which the surface is brought into contact with a chemical polishing bath according to the invention.
  • the contacting of the metal surface with the bath can be carried out in any suitable manner, for example by immersion.
  • the contact time of the surface to be polished with the bath must be sufficient to achieve effective polishing of the surface. However, it cannot exceed a critical value beyond which the bath loses its polishing properties.
  • the optimum contact time depends on many parameters such as the grade of steel, the configuration and the initial roughness of the surface to be polished, the composition of the bath, the working temperature, the agitation of the bath in contact with the surface. , the ratio between the area of the surface to be polished and the volume of the bath; it must be determined in each particular case by routine work in the laboratory.
  • the bath is carried out at a temperature between 20 and 65 ° C, preferably between 35 and 50 ° C, at normal atmospheric pressure, and the surface to be polished in contact with the bath for a time between 5 and 12 hours.

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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)
  • Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
  • Chemical Treatment Of Metals (AREA)

Abstract

Bains pour le polissage chimique de surfaces en acier inoxydable, comprenant, en solution aqueuse, un mélange d'acide chlorhydrique, d'acide nitrique et d'acide phosphorique, un acide hydroxybenzoïque éventuellement substitué et une amine.Baths for the chemical polishing of stainless steel surfaces, comprising, in aqueous solution, a mixture of hydrochloric acid, nitric acid and phosphoric acid, an optionally substituted hydroxybenzoic acid and an amine.

Description

La présente invention a pour objet la composition de bains pour le polissage chimique de surfaces en acier inoxydable.The present invention relates to the composition of baths for the chemical polishing of stainless steel surfaces.

Le polissage chimique des surfaces métalliques constitue une technique bien connue (Polissage électrolytique et chimique des métaux - W.J. Mc G. TEGART - Dunod - 1960 - p. 122 et suivantes); elle consiste à traiter les surfaces métalliques à polir avec des bains oxydants. Pour le polissage chimique des aciers inoxydables austénitiques, on utilise généralement des bains comprenant un mélange, en solution aqueuse, d'acides chlorhydrique, phosphorique et nitrique (brevet US-A-2662814). Pour améliorer la qualité du polissage, il est habituel d'incorporer à ces bains des additifs adéquats tels que des agents tensio-actifs, des régulateurs de viscosité et des agents de brillantage. Ainsi, dans le brevet US-A-3709824, on décrit une composition d'un bain pour le polissage chimique de surfaces en acier inoxydable, comprenant, en solution aqueuse, un mélange d'acide chlorhydrique, d'acide nitrique et d'acide phosphorique, un régulateur de viscosité choisi parmi les polymères hydrosolubles, un surfactant et de l'acide sulfosalicylique à titre d'agent de brillantage.Chemical polishing of metal surfaces is a well-known technique (electrolytic and chemical polishing of metals - W.J. Mc G. TEGART - Dunod - 1960 - p. 122 et seq.); it consists of treating the metal surfaces to be polished with oxidizing baths. For the chemical polishing of austenitic stainless steels, baths are generally used comprising a mixture, in aqueous solution, of hydrochloric, phosphoric and nitric acids (patent US-A-2662814). To improve the quality of the polishing, it is usual to incorporate in these baths suitable additives such as surfactants, viscosity regulators and brighteners. Thus, in patent US-A-3709824, a composition of a bath for the chemical polishing of stainless steel surfaces is described, comprising, in aqueous solution, a mixture of hydrochloric acid, nitric acid and acid. phosphoric, a viscosity regulator chosen from water-soluble polymers, a surfactant and sulfosalicylic acid as a brightening agent.

Ces bains de polissage connus présentent la particularité d'attaquer le métal à très grande vitesse. Un traitement de polissage d'une surface en acier inoxydable avec de tels bains ne peut généralement pas excéder quelques minutes, sous peine d'engendrer des corrosions locales. Cette grande vitesse d'action des bains de polissage connus est un inconvénient, car elle les rend inutilisables pour certaines applications, notamment pour le polissage de la face interne des parois de cuves de grandes dimensions, telles que des chaudières, des autoclaves ou des cristalliseurs. Le temps nécessité pour le remplissage et la vidange de telles cuves étant en général largement supérieur à la durée du traitement de polissage chimique optimum, il devient en effet impossible d'obtenir un poli uniforme de la paroi, certaines zones de celle-ci étant insuffisamment polies, d'autres étant profondément corrodées. La grande vitesse d'action des bains de polissage chimique connus rend par ailleurs le contrôle du polissage difficile.These known polishing baths have the particularity of attacking the metal at very high speed. A polishing treatment of a stainless steel surface with such baths can generally not exceed a few minutes, on pain of causing local corrosions. This high speed of action of known polishing baths is a drawback, because it makes them unusable for certain applications, in particular for the polishing of the internal face of the walls of large tanks, such as boilers, autoclaves or crystallizers. The time required for filling and emptying such tanks being generally much greater than the duration of the optimum chemical polishing treatment, it indeed becomes impossible to obtain a uniform polish of the wall, certain areas of the latter being insufficiently others are deeply corroded. The high speed of action of known chemical polishing baths also makes polishing control difficult.

Dans le brevet EP-B-19964 (SOLVAY & Cie), on décrit des bains de polissage chimique à action très lente, qui évitent dès lors les inconvénients précités. Ces bains connus comprennent, en solution aqueuse, un mélange d'acides chlorhydrique, nitrique et phosphorique, de l'acide sulfosalicylique, du chlorure d'alkylpyridinium et de la méthylcellulose. Ces bains de polissage connus à action lente sont conçus pour travailler à des températures au moins égales à 40°C, généralement comprises entre 45 et 100°C.In patent EP-B-19964 (SOLVAY & Cie), chemical polishing baths with very slow action are described, which therefore avoid the abovementioned drawbacks. These known baths include, in aqueous solution, a mixture of hydrochloric, nitric and phosphoric acids, sulfosalicylic acid, alkylpyridinium chloride and methylcellulose. These known slow-action polishing baths are designed to work at temperatures at least equal to 40 ° C., generally between 45 and 100 ° C.

L'invention vise à fournir des bains conçus pour réaliser un polissage chimique lent et efficace de surfaces en acier inoxydable, à des températures de travail inférieures à 50°C.The invention aims to provide baths designed to carry out slow and effective chemical polishing of stainless steel surfaces, at working temperatures below 50 ° C.

En conséquence, l'invention concerne des bains pour le polissage chimique de surfaces en acier inoxydable, comprenant, en solution aqueuse, un mélange d'acide chlorhydrique, d'acide nitrique et d'acide phosphorique, un acide hydroxybenzoïque éventuellement substitué et une amine hydrosoluble.The invention therefore relates to baths for the chemical polishing of stainless steel surfaces, comprising, in aqueous solution, a mixture of hydrochloric acid, nitric acid and phosphoric acid, an optionally substituted hydroxybenzoic acid and an amine. water soluble.

Dans les bains selon l'invention, l'acide hydroxybenzoïque sert d'agent de brillantage. Il peut être non substitué tel que l'acide salicylique ou substitué tel que l'acide sulfosalicylique. L'acide salicylique est préféré.In the baths according to the invention, hydroxybenzoic acid serves as a brightening agent. It can be unsubstituted such as salicylic acid or substituted such as sulfosalicylic acid. Salicylic acid is preferred.

L'amine peut être sélectionnée parmi les amines primaires, les amines secondaires et les amines tertiaires. On préfère les amines dont la molécule comprend plus de 10 atomes de carbone, par exemple entre 11 et 20 atomes de carbone. Les alkylamines primaires comportant de 11 à 16 atomes de carbone dans leur molécule sont préférées. Les bains selon l'invention peuvent comprendre un mélange d'amines. La teneur optimum en amine dépend de la nature de l'amine sélectionnée. En règle générale, elle se situe entre 0,001 et 1 g par litre de la solution aqueuse.The amine can be selected from primary amines, secondary amines and tertiary amines. Amines are preferred, the molecule of which comprises more than 10 carbon atoms, for example between 11 and 20 carbon atoms. Primary alkylamines having 11 to 16 carbon atoms in their molecule are preferred. The baths according to the invention can comprise a mixture of amines. Optimal amine content depends on the nature of the amine selected. Typically, it is between 0.001 and 1 g per liter of the aqueous solution.

Dans une forme de réalisation particulière de l'invention, la solution aqueuse du bain comprend, en plus de l'amine, un additif sélectionné parmi l'acide perchlorique et les sels hydrosolubles de l'acide perchlorique. La teneur optimum en cet additif se situe entre 0,001 et 0,5 mole par litre de la solution aqueuse.In a particular embodiment of the invention, the aqueous solution of the bath comprises, in addition to the amine, an additive selected from perchloric acid and the water-soluble salts of perchloric acid. The optimum content of this additive is between 0.001 and 0.5 mole per liter of the aqueous solution.

Dans une autre forme de réalisation des bains selon l'invention, la solution aqueuse contient un additif hydrosoluble capable de décomposer l'acide nitreux. Cet additif a pour fonction de décomposer une partie au moins de l'acide nitreux qui se forme pendant le polissage d'une surface en acier, comme conséquence d'une oxydation d'ions ferreux libérés dans le bain au cours du polissage. Il est de préférence sélectionné parmi l'urée et ses dérivés, tels que la thiourée et les uréines, et sa teneur optimum se situe entre 0,01 et 5 g par litre de la solution aqueuse. Les bains conformes à cette forme de réalisation de l'invention sont spécialement adaptés aux traitements de polissage dans lesquels le rapport entre la surface en contact avec le bain et le volume de celui-ci est supérieur 10 m⁻¹.In another embodiment of the baths according to the invention, the aqueous solution contains a water-soluble additive capable of breaking down nitrous acid. The function of this additive is to decompose at least part of the nitrous acid which forms during the polishing of a steel surface, as a consequence of oxidation of ferrous ions released in the bath during polishing. It is preferably selected from urea and its derivatives, such as thiourea and ureines, and its optimum content is between 0.01 and 5 g per liter of the aqueous solution. The baths in accordance with this embodiment of the invention are specially adapted for polishing treatments in which the ratio between the surface in contact with the bath and the volume thereof is greater than 10 m⁻¹.

Il est préférable que les bains selon l'invention soient exempts d'ions ferricyanure et d'ions ferrocyanure, surtout lorsqu'ils ne contiennent pas d'acide perchlorique.It is preferable that the baths according to the invention are free from ferricyanide ions and ferrocyanide ions, especially when they do not contain perchloric acid.

Les quantités pondérales adéquates des divers constituants des bains selon l'invention dépendent de la nuance de l'acier inoxydable soumis au polissage ainsi que des conditions du polissage, notamment du profil de l'objet en acier soumis au polissage, de son volume, du volume du bain, de sa température et de l'agitation à laquelle on le soumet éventuellement. Elles doivent dès lors être déterminées dans chaque cas particulier par des essais de routine au laboratoire. Des exemples de bains conformes à l'invention, adaptés au polissage d'aciers inoxydables austénitiques alliés au chrome et au nickel, à des températures comprises entre 20 et 50°C comprennent, par litre de solution aqueuse :

  • · entre 0,5 et 5 moles d'acide chlorhydrique (de préférence 1-3 moles),
  • · entre 0,005 et 1 mole d'acide nitrique (de préférence 0,05-0,5 mole),
  • · entre 0,005 et 1 mole d'acide phosphorique (de préférence 0,01-0,5 mole),
  • · entre 0,001 et 5 g d'acide hydroxybenzoïque substitué ou non substitué (de préférence 0,005-0,3 g, dans le cas de l'acide non substitué),
  • · entre 0,001 et 1 g d'amine (de préférence 0,005 - 0,300g)
  • · entre 0 et 0,5 mole de l'additif sélectionné parmi l'acide perchlorique et les sels hydrosolubles de l'acide perchlorique (de préférence 0,001-0,2 mole),
  • · entre 0 et 5 g de l'additif capable de décomposer l'acide nitreux (de préférence 0,01 et 5 g).
The adequate weight quantities of the various constituents of the baths according to the invention depend on the grade of the stainless steel subjected to polishing as well as on the polishing conditions, in particular on the profile of the steel object subjected to polishing, on its volume, on the volume of the bath, its temperature and the agitation to which it is possibly subjected. They must therefore be determined in each particular case by routine laboratory tests. Examples of baths according to the invention, suitable for polishing austenitic stainless steels alloyed with chromium and nickel, at temperatures between 20 and 50 ° C. include, per liter of aqueous solution :
  • Between 0.5 and 5 moles of hydrochloric acid (preferably 1-3 moles),
  • Between 0.005 and 1 mole of nitric acid (preferably 0.05-0.5 mole),
  • Between 0.005 and 1 mole of phosphoric acid (preferably 0.01-0.5 mole),
  • Between 0.001 and 5 g of substituted or unsubstituted hydroxybenzoic acid (preferably 0.005-0.3 g, in the case of unsubstituted acid),
  • Between 0.001 and 1 g of amine (preferably 0.005 - 0.300 g)
  • Between 0 and 0.5 mole of the additive selected from perchloric acid and the water-soluble salts of perchloric acid (preferably 0.001-0.2 mole),
  • · Between 0 and 5 g of the additive capable of breaking down nitrous acid (preferably 0.01 and 5 g).

Les bains de polissage selon l'invention peuvent éventuellement contenir des additifs habituellement présents dans les bains connus pour le polissage chimique des métaux, par exemple des agents tensio-actifs, des alcools et des régulateurs de viscosité. Ils peuvent notamment comprendre un composé abiétique hydrosoluble qui est un composé chimique comprenant un radical abiétyle de formule générale :

Figure imgb0001

ou un radical hydroabiétyle ou déhydroabiétyle.The polishing baths according to the invention may optionally contain additives usually present in baths known for the chemical polishing of metals, for example surfactants, alcohols and viscosity regulators. They can in particular comprise a water-soluble abietic compound which is a chemical compound comprising an abietyl radical of general formula:
Figure imgb0001
or a hydroabietyl or dehydroabietyl radical.

Conformément à l'invention, le composé abiétique doit être soluble dans la solution aqueuse.According to the invention, the abietic compound must be soluble in the aqueous solution.

Des composés abiétiques utilisables dans les bains selon l'invention sont les abiétamines.Abietic compounds which can be used in the baths according to the invention are abietamines.

Des abiétamines spécialement recommandées pour les bains selon l'invention sont celles de formule générale :

Figure imgb0002

dans laquelle :

  • R₁ désigne un radical abiétyle, hydroabiétyle ou déhydroabiétyle défini ci-dessus,
  • X₁ désigne un radical comprenant au moins un groupe carbonyle, et
  • X₂ désigne un atome d'hydrogène ou un radical comprenant au moins un groupe carbonyle.
Abietamines specially recommended for baths according to the invention are those of general formula:
Figure imgb0002
in which :
  • R₁ denotes an abietyl, hydroabietyl or dehydroabietyl radical defined above,
  • X₁ denotes a radical comprising at least one carbonyl group, and
  • X₂ denotes a hydrogen atom or a radical comprising at least one carbonyl group.

Des exemples de telles abiétamines, qui conviennent bien dans les bains selon l'invention, sont celles dans lesquelles l'un au moins des radicaux X₁ et X₂ est un radical de formule générale :



        -CH₂-R₂



dans laquelle R₂ désigne un radical alkyle linéaire ou cyclique, substitué ou non substitué, saturé ou insaturé, comprenant au moins un groupe carbonyle. Parmi ces composés, on préfère ceux dans lesquels le groupe -CH₂- est relié à un groupe carbonyle du radical R₂ par un atome de carbone portant au moins un atome d'hydrogène. De telles abiétamines substituées et le moyen de les obtenir sont décrits dans le brevet GB-A-734665. Des exemples d'abiétamines de ce type, utilisables dans les bains selon l'invention, sont celles dans lesquelles le radical alkyle R₂ est sélectionné parmi les radicaux acétonyle, 2-céto butyle, 4-méthyl 2-céto pentényle-3, 4-hydroxy 4-méthyl 2-céto pentyle, 2-céto cyclopentyle, 4-hydroxy 2-céto pentényle-3, 2-céto cyclohexyle, 2,5-dicéto hexyle et 2-phényl 2-céto éthyle.Examples of such abietamines, which are very suitable in the baths according to the invention, are those in which at least one of the radicals X₁ and X₂ is a radical of general formula:



-CH₂-R₂



wherein R₂ denotes a linear or cyclic alkyl radical, substituted or unsubstituted, saturated or unsaturated, comprising at least one carbonyl group. Among these compounds, preference is given to those in which the group —CH₂- is linked to a carbonyl group of the radical R₂ by a carbon atom carrying at least one hydrogen atom. Such substituted abietamines and the means of obtaining them are described in GB-A-734665. Examples of abietamines of this type, which can be used in the baths according to the invention, are those in which the alkyl radical R₂ is selected from acetonyl, 2-keto butyl, 4-methyl 2-keto-pentenyl-3, 4- radicals. hydroxy 4-methyl 2-keto pentyl, 2-keto cyclopentyl, 4-hydroxy 2-keto pentenyl-3, 2-keto cyclohexyl, 2,5-diketo hexyl and 2-phenyl 2-keto ethyl.

Les bains selon l'invention peuvent également contenir des produits de la marque DEHYQUART (Henkel), qui sont des agents tensioactifs sélectionnés parmi les sels d'alkylpyridinium et les sels d'ammonium quaternaires, comprenant des radicaux alkyl, phényl ou benzyl, substitués ou non substitués.The baths according to the invention may also contain products of the DEHYQUART brand (Henkel), which are surfactants selected from alkylpyridinium salts and quaternary ammonium salts, comprising alkyl, phenyl or benzyl radicals, substituted or not substituted.

Les bains selon l'invention conviennent pour le polissage chimique de toutes surfaces en acier inoxydable austénitique. Ils sont spécialement adaptés au polissage des aciers austénitiques contenant entre 16 et 26 % en poids de chrome et entre 6 et 22 % en poids de nickel, tels que les aciers de nuances 18/8 et 18/10, contenant éventuellement du molybdène (par exemple les aciers AISI-304, 304L, 316 et 316L). Les bains selon l'invention présentent la particularité de réaliser le polissage de tels aciers à vitesse lente, nécessitant généralement un temps de contact compris entre 3 et 12 heures. Ils peuvent être utilisés à toutes températures comprises entre 20°C et la température d'ébullition. Ils présentent toutefois la particularité remarquable de présenter une excellente efficacité à des températures inférieures à 50°C, généralement comprise entre 35 et 45°C, à la pression atmosphérique normale, ce qui facilite leur mise en oeuvre et simplifie les mesures à prendre pour assurer la salubrité des ateliers de polissage. Les bains selon l'invention présentent l'avantage supplémentaire de réaliser des polissages de bonne qualité d'assemblages soudés selon les règles de l'art.The baths according to the invention are suitable for polishing chemical of all surfaces in austenitic stainless steel. They are specially suitable for polishing austenitic steels containing between 16 and 26% by weight of chromium and between 6 and 22% by weight of nickel, such as steels of grades 18/8 and 18/10, optionally containing molybdenum (for example example AISI-304, 304L, 316 and 316L steels). The baths according to the invention have the particularity of carrying out the polishing of such steels at slow speed, generally requiring a contact time of between 3 and 12 hours. They can be used at all temperatures between 20 ° C and the boiling temperature. However, they have the remarkable characteristic of having excellent efficiency at temperatures below 50 ° C, generally between 35 and 45 ° C, at normal atmospheric pressure, which facilitates their implementation and simplifies the measures to be taken to ensure the health of the polishing workshops. The baths according to the invention have the additional advantage of performing good quality polishing of welded assemblies according to the rules of the art.

L'invention concerne aussi un procédé pour le polissage d'une surface en acier inoxydable, selon lequel on met la surface en contact avec un bain de polissage chimique conforme à l'invention.The invention also relates to a method for polishing a stainless steel surface, according to which the surface is brought into contact with a chemical polishing bath according to the invention.

Dans l'exécution du procédé selon l'invention, la mise en contact de la surface métallique avec le bain peut être réalisée de toute manière adéquate, par exemple par immersion. Le temps de contact de la surface à polir avec le bain doit être suffisant pour réaliser un polissage efficace de la surface. Il ne peut toutefois pas excéder une valeur critique au-delà de laquelle le bain perd ses propriétés polissantes. Le temps de contact optimum dépend de nombreux paramètres tels que la nuance de l'acier, la configuration et la rugosité initiale de la surface à polir, la composition du bain, la température de travail, l'agitation du bain au contact de la surface, le rapport entre l'aire de la surface à polir et le volume du bain; il doit être déterminé dans chaque cas particulier par un travail de routine au laboratoire.In carrying out the method according to the invention, the contacting of the metal surface with the bath can be carried out in any suitable manner, for example by immersion. The contact time of the surface to be polished with the bath must be sufficient to achieve effective polishing of the surface. However, it cannot exceed a critical value beyond which the bath loses its polishing properties. The optimum contact time depends on many parameters such as the grade of steel, the configuration and the initial roughness of the surface to be polished, the composition of the bath, the working temperature, the agitation of the bath in contact with the surface. , the ratio between the area of the surface to be polished and the volume of the bath; it must be determined in each particular case by routine work in the laboratory.

Dans une forme d'exécution préférée du procédé selon l'invention, le bain est mis en oeuvre à une température comprise entre 20 et 65°C, de préférence entre 35 et 50°C, à la pression atmosphérique normale, et on maintient la surface à polir au contact du bain pendant un temps compris entre 5 et 12 heures.In a preferred embodiment of the method according to the invention, the bath is carried out at a temperature between 20 and 65 ° C, preferably between 35 and 50 ° C, at normal atmospheric pressure, and the surface to be polished in contact with the bath for a time between 5 and 12 hours.

L'intérêt de l'invention va être mis en évidence à la lecture des exemples exposés ci-après.The advantage of the invention will be highlighted on reading the examples set out below.

Dans les exemples dont la description suit, on a utilisé des plaques en acier inoxydable de nuance 18/10 [acier allié au chrome (18,0 %) et au nickel (10,0 %) et exempt de molybdène].In the examples, the description of which follows, stainless steel plates of grade 18/10 (steel alloyed with chromium (18.0%) and nickel (10.0%) and free from molybdenum) were used.

Dans chaque exemple, la plaque a été immergée dans le bain de polissage, maintenu à une température sensiblement constante et soumis à une agitation modérée. A l'issue de la période d'immersion, la plaque a été retirée du bain, rincée à l'eau déminéralisée et séchée. On a mesuré les paramètres suivants :

  • · la profondeur moyenne d'attaque du métal, définie par la relation
    Figure imgb0003
     où
    S
    désigne l'aire de la plaque (en cm²),
    d
    désigne la masse spécifique du métal (en g/cm³),
    ΔP
    désigne la perte en poids (en g) de la plaque pendant l'immersion dans le bain,
    Δe
    désigne la profondeur d'attaque (µm);
  • · la rugosité moyenne arithmétique Ra, qui est la déviation moyenne par rapport à la surface moyenne de la plaque [Encyclopedia of Materials Science and Engineering, Michael B. Bever, Vol. 6, 1986, Pergamon Press, pages 4806 à 4808 (page 4806)] :
    Figure imgb0004
     les mesures étant effectuées avec un palpeur muni d'une pointe présentant un rayon de courbure de 5 µm et le calculateur travaillant avec une valeur de cut-off égale à 0,25mm;
  • · la brillance de la surface sous un angle d'incidence de 20 degrés (selon la norme ASTM D523).
In each example, the plate was immersed in the polishing bath, kept at a substantially constant temperature and subjected to moderate agitation. At the end of the immersion period, the plate was removed from the bath, rinsed with demineralized water and dried. The following parameters were measured:
  • · The average depth of attack of the metal, defined by the relation
    Figure imgb0003
     or
    S
    designates the area of the plate (in cm²),
    d
    denotes the specific mass of the metal (in g / cm³),
    ΔP
    designates the weight loss (in g) of the plate during immersion in the bath,
    Δe
    denotes the depth of attack (µm);
  • · The arithmetic mean roughness R a , which is the mean deviation from the mean surface of the plate [Encyclopedia of Materials Science and Engineering, Michael B. Bever, Vol. 6, 1986, Pergamon Press, pages 4806 to 4808 (page 4806)]:
    Figure imgb0004
     the measurements being carried out with a feeler provided with a point having a radius of curvature of 5 μm and the calculator working with a cut-off value equal to 0.25 mm;
  • · The gloss of the surface at an angle of incidence of 20 degrees (according to standard ASTM D523).

Première série d'exemples : exemples conformes à l'invention.First series of examples: examples according to the invention. Exemple 1Example 1

On a mis en oeuvre un bain de polissage conforme à l'invention, comprenant, par litre :

  • · 1,3 mole d'acide chlorhydrique,
  • · 0,25 mole d'acide nitrique,
  • · 0,15 mole d'acide phosphorique,
  • · 0,1 g d'acide salicylique,
  • · 0,1 g de tripentylamine,
  • · 0,005 mole d'acide perchlorique. Les conditions opératoires furent les suivantes :
  • · volume du bain : 970 cm³,
  • · aire de la surface soumise au polissage : 87,3 cm²,
  • · température : 45°C,
  • · durée de l'immersion : 3 heures 30 minutes.
A polishing bath in accordance with the invention was used, comprising, per liter:
  • 1.3 moles of hydrochloric acid,
  • 0.25 mole of nitric acid,
  • 0.15 mole of phosphoric acid,
  • 0.1 g salicylic acid,
  • 0.1 g of tripentylamine,
  • 0.005 mole of perchloric acid. The operating conditions were as follows:
  • Bath volume: 970 cm³,
  • · Surface area subject to polishing: 87.3 cm²,
  • Temperature: 45 ° C,
  • · Duration of the immersion: 3 hours 30 minutes.

On a relevé les résultats suivants :

  • · rugosité moyenne arithmétique :
    • · avant le polissage : 0,29 µm,
    • · après le polissage : 0,21 µm,
  • · brillance : 12%.
The following results were noted:
  • Arithmetic mean roughness:
    • · Before polishing: 0.29 µm,
    • · After polishing: 0.21 µm,
  • Gloss: 12%.

Exemple 2Example 2

On a mis en oeuvre un bain de polissage conforme à l'invention, comprenant, par litre :

  • · 1,5 mole d'acide chlorhydrique,
  • · 0,2 mole d'acide nitrique,
  • · 0,2 mole d'acide phosphorique,
  • · 0,1 g d'acide salicylique,
  • · 0,075 g de trioctylamine,
  • · 0,005 mole d'acide perchlorique.
A polishing bath in accordance with the invention was used, comprising, per liter:
  • 1.5 moles of hydrochloric acid,
  • 0.2 mole of nitric acid,
  • 0.2 mole of phosphoric acid,
  • 0.1 g salicylic acid,
  • 0.075 g of trioctylamine,
  • 0.005 mole of perchloric acid.

Les conditions opératoires furent les suivantes :

  • · volume du bain : 970 cm³,
  • · aire de la surface soumise au polissage : 87,3 cm²,
  • · température : 45°C,
  • · durée de l'immersion : 3 heures 15 minutes.
The operating conditions were as follows:
  • Bath volume: 970 cm³,
  • · Surface area subject to polishing: 87.3 cm²,
  • Temperature: 45 ° C,
  • · Duration of the immersion: 3 hours 15 minutes.

On a relevé les résultats suivants :

  • · profondeur d'attaque : 31,3 µm,
  • · rugosité moyenne arithmétique :
    • · avant le polissage : 0,29 µm,
    • · après le polissage : 0,18 µm,
  • · brillance : 17 %.
The following results were noted:
  • Attack depth: 31.3 µm,
  • Arithmetic mean roughness:
    • · Before polishing: 0.29 µm,
    • · After polishing: 0.18 µm,
  • Gloss: 17%.

Exemple 3Example 3

On a mis en oeuvre un bain de polissage conforme à l'invention, comprenant, par litre :

  • · 1,5 mole d'acide chlorhydrique,
  • · 0,2 mole d'acide nitrique,
  • · 0,2 mole d'acide phosphorique,
  • · 0,1 g d'acide salicylique,
  • · 0,075 g de dihexylamine,
  • · 0,005 mole d'acide perchlorique.
A polishing bath in accordance with the invention was used, comprising, per liter:
  • 1.5 moles of hydrochloric acid,
  • 0.2 mole of nitric acid,
  • 0.2 mole of phosphoric acid,
  • 0.1 g salicylic acid,
  • 0.075 g of dihexylamine,
  • 0.005 mole of perchloric acid.

Les conditions opératoires furent les suivantes :

  • · volume du bain : 970 cm³,
  • · aire de la surface soumise au polissage : 87,3 cm²,
  • · température : 45°C,
  • · durée de l'immersion : 3 heures 25 minutes.
The operating conditions were as follows:
  • Bath volume: 970 cm³,
  • · Surface area subject to polishing: 87.3 cm²,
  • Temperature: 45 ° C,
  • · Duration of the immersion: 3 hours 25 minutes.

On a relevé les résultats suivants :

  • · profondeur d'attaque : 27,1 µm,
  • · rugosité moyenne arithmétique :
    • · avant le polissage : 0,31 µm,
    • · après le polissage : 0,22 µm,
  • · brillance : 13 %.
The following results were noted:
  • Attack depth: 27.1 µm,
  • Arithmetic mean roughness:
    • · Before polishing: 0.31 µm,
    • · After polishing: 0.22 µm,
  • Gloss: 13%.

Exemple 4Example 4

On a mis en oeuvre un bain de polissage conforme à l'invention, comprenant, par litre :

  • · 1,5 mole d'acide chlorhydrique,
  • · 0,2 mole d'acide nitrique,
  • · 0,2 mole d'acide phosphorique,
  • · 0,1 g d'acide salicylique,
  • · 0,075 g de laurylamine,
A polishing bath in accordance with the invention was used, comprising, per liter:
  • 1.5 moles of hydrochloric acid,
  • 0.2 mole of nitric acid,
  • 0.2 mole of phosphoric acid,
  • 0.1 g salicylic acid,
  • 0.075 g of laurylamine,

Les conditions opératoires furent les suivantes :

  • · volume du bain : 970 cm³,
  • · aire de la surface soumise au polissage : 87,3 cm²,
  • · température : 45°C,
  • · durée de l'immersion : 3 heures 50 minutes.
The operating conditions were as follows:
  • Bath volume: 970 cm³,
  • · Surface area subject to polishing: 87.3 cm²,
  • Temperature: 45 ° C,
  • · Duration of the immersion: 3 hours 50 minutes.

On a relevé les résultats suivants :

  • · profondeur d'attaque : 25,1 µm,
  • · rugosité moyenne arithmétique :
    • · avant le polissage : 0,28 µm,
    • · après le polissage : 0,09 µm,
  • · brillance : 36 %.
The following results were noted:
  • Attack depth: 25.1 µm,
  • Arithmetic mean roughness:
    • · Before polishing: 0.28 µm,
    • · After polishing: 0.09 µm,
  • Gloss: 36%.

Exemple 5Example 5

On a mis en oeuvre un bain de polissage conforme à l'invention, comprenant, par litre :

  • · 1,5 mole d'acide chlorhydrique,
  • · 0,2 mole d'acide nitrique,
  • · 0,2 mole d'acide phosphorique,
  • · 0,1 g d'acide salicylique,
  • · 0,075 g de laurylamine,
  • · 0,005 mole d'acide perchlorique.
A polishing bath in accordance with the invention was used, comprising, per liter:
  • 1.5 moles of hydrochloric acid,
  • 0.2 mole of nitric acid,
  • 0.2 mole of phosphoric acid,
  • 0.1 g salicylic acid,
  • 0.075 g of laurylamine,
  • 0.005 mole of perchloric acid.

Les conditions opératoires furent les suivantes :

  • · volume du bain : 970 cm³,
  • · aire de la surface soumise au polissage : 87,3 cm²,
  • · température : 45°C,
  • · durée de l'immersion : 4 heures.
The operating conditions were as follows:
  • Bath volume: 970 cm³,
  • · Surface area subject to polishing: 87.3 cm²,
  • Temperature: 45 ° C,
  • · Duration of the immersion: 4 hours.

On a relevé les résultats suivants :

  • · profondeur d'attaque : 27,3 µm,
  • · rugosité moyenne arithmétique :
    • · avant le polissage : 0,27 µm,
    • · après le polissage : 0,08 µm,
  • · brillance : 38 %.
The following results were noted:
  • Attack depth: 27.3 µm,
  • Arithmetic mean roughness:
    • · Before polishing: 0.27 µm,
    • · After polishing: 0.08 µm,
  • Gloss: 38%.

Exemple 6Example 6

On a mis en oeuvre un bain de polissage conforme à l'invention, comprenant, par litre :

  • · 1,5 mole d'acide chlorhydrique,
  • · 0,2 mole d'acide nitrique,
  • · 0,2 mole d'acide phosphorique,
  • · 0,1 g d'acide salicylique,
  • · 0,075 g de laurylamine,
  • · 0,005 mole d'acide perchlorique,
  • · 0,1 g d'urée.
A polishing bath in accordance with the invention was used, comprising, per liter:
  • 1.5 moles of hydrochloric acid,
  • 0.2 mole of nitric acid,
  • 0.2 mole of phosphoric acid,
  • 0.1 g salicylic acid,
  • 0.075 g of laurylamine,
  • 0.005 mole of perchloric acid,
  • 0.1 g of urea.

Les conditions opératoires furent les suivantes :

  • · volume du bain : 725 cm³,
  • · aire de la surface soumise au polissage : 87,3 cm²,
  • · température : 45°C,
  • · durée de l'immersion : 4 heures.
The operating conditions were as follows:
  • Bath volume: 725 cm³,
  • · Surface area subject to polishing: 87.3 cm²,
  • Temperature: 45 ° C,
  • · Duration of the immersion: 4 hours.

On a relevé les résultats suivants :

  • · profondeur d'attaque : 26,2 µm,
  • · rugosité moyenne arithmétique :
    • · avant le polissage : 0,22 µm,
    • · après le polissage : 0,07 µm,
  • · brillance : 37 %.
The following results were noted:
  • Attack depth: 26.2 µm,
  • Arithmetic mean roughness:
    • · Before polishing: 0.22 µm,
    • · After polishing: 0.07 µm,
  • Gloss: 37%.

Exemple 7Example 7

On a mis en oeuvre un bain de polissage conforme à l'invention, comprenant, par litre :

  • · 1,3 mole d'acide chlorhydrique,
  • · 0,2 mole d'acide nitrique,
  • · 0,1 mole d'acide phosphorique,
  • · 0,2 g d'acide salicylique,
  • · 0,1 g de tridécylamine,
  • · 0,005 mole d'acide perchlorique.
A polishing bath in accordance with the invention was used, comprising, per liter:
  • 1.3 moles of hydrochloric acid,
  • 0.2 mole of nitric acid,
  • 0.1 mole of phosphoric acid,
  • 0.2 g salicylic acid,
  • 0.1 g of tridecylamine,
  • 0.005 mole of perchloric acid.

Les conditions opératoires furent les suivantes :

  • · volume du bain : 930 cm³,
  • · aire de la surface soumise au polissage : 84 cm²,
  • · température : 45°C,
  • · durée de l'immersion : 4 heures 50 minutes.
The operating conditions were as follows:
  • Bath volume: 930 cm³,
  • · Surface area subject to polishing: 84 cm²,
  • Temperature: 45 ° C,
  • · Duration of the immersion: 4 hours 50 minutes.

On a relevé les résultats suivants :

  • · profondeur moyenne d'attaque : 38,6 µm,
  • · rugosité moyenne arithmétique :
    • · avant le polissage : 0,25 µm,
    • · après le polissage : 0,10 µm,
  • · brillance : 33%.
The following results were noted:
  • · Average depth of attack: 38.6 µm,
  • Arithmetic mean roughness:
    • · Before polishing: 0.25 µm,
    • · After polishing: 0.10 µm,
  • Gloss: 33%.

Exemple 8Example 8

On a mis en oeuvre un bain de polissage conforme à l'invention, contenant, par litre :

  • · 1,6 mole d'acide chlorhydrique,
  • · 0,2 mole d'acide nitrique,
  • · 0,2 mole d'acide phosphorique,
  • · 0,1 g d'acide salicylique,
  • · 0,075 g de dodécylamine,
  • · 0,005 mole d'acide perchlorique
  • · 0,5 g d'urée.
A polishing bath was used in accordance with the invention, containing, per liter:
  • 1.6 mole of hydrochloric acid,
  • 0.2 mole of nitric acid,
  • 0.2 mole of phosphoric acid,
  • 0.1 g salicylic acid,
  • 0.075 g of dodecylamine,
  • 0.005 mole of perchloric acid
  • 0.5 g of urea.

Les conditions opératoires furent les suivantes :

  • · volume du bain : 1050 cm³,
  • · aire de la surface soumise au polissage : 63 cm²,
  • · température : 35°C,
  • · durée de l'immersion : 8 heures 40 minutes.
The operating conditions were as follows:
  • Bath volume: 1050 cm³,
  • · Surface area subject to polishing: 63 cm²,
  • Temperature: 35 ° C,
  • · Duration of the immersion: 8 hours 40 minutes.

On a relevé les résultats suivants :

  • · profondeur moyenne d'attaque : 30 µm,
  • · rugosité moyenne arithmétique
    • · avant le polissage : 0,25 µm,
    • · après le polissage : 0,09 µm,
  • · Brillance : 28 %.
The following results were noted:
  • · Average attack depth: 30 µm,
  • Arithmetic mean roughness
    • · Before polishing: 0.25 µm,
    • · After polishing: 0.09 µm,
  • · Gloss: 28%.

Exemple 9Example 9

On a mis en oeuvre un bain de polissage conforme à l'invention, comprenant, par litre :

  • · 1,7 mole d'acide chlorhydrique,
  • · 0,2 mole d'acide nitrique,
  • · 0,25 mole d'acide phosphorique,
  • · 0,1 g d'acide salicylique,
  • · 0,050 g de myristylamine,
  • · 0,005 mole d'acide perchlorique.
A polishing bath in accordance with the invention was used, comprising, per liter:
  • 1.7 moles of hydrochloric acid,
  • 0.2 mole of nitric acid,
  • 0.25 mole of phosphoric acid,
  • 0.1 g salicylic acid,
  • 0.050 g of myristylamine,
  • 0.005 mole of perchloric acid.

Les conditions opératoires furent les suivantes :

  • · volume du bain : 970 cm³,
  • · aire de la surface soumise au polissage : 87,3 cm²,
  • · température : 45°C,
  • · durée de l'immersion : 3 heures 50 minutes.
The operating conditions were as follows:
  • Bath volume: 970 cm³,
  • · Surface area subject to polishing: 87.3 cm²,
  • Temperature: 45 ° C,
  • · Duration of the immersion: 3 hours 50 minutes.

On a relevé les résultats suivants :

  • · rugosité moyenne arithmétique :
    • · avant le polissage : 0,22 µm,
    • · après le polissage : 0,11 µm,
  • · brillance : 21 %.
The following results were noted:
  • Arithmetic mean roughness:
    • · Before polishing: 0.22 µm,
    • · After polishing: 0.11 µm,
  • Gloss: 21%.

Seconde série d'exemples : exemples de référenceSecond series of examples: reference examples

Cette série d'exemple concerne des essais qui ont été effectués avec des bains qui ne sont pas conformes à l'invention.This series of examples relates to tests which have been carried out with baths which are not in accordance with the invention.

Exemple 10Example 10

On a mis en oeuvre un bain de polissage comprenant, par litre :

  • · 1,5 mole d'acide chlorhydrique,
  • · 0,2 mole d'acide nitrique,
  • · 0,2 mole d'acide phosphorique,
  • · 0,1 g d'acide salicylique.
A polishing bath was used comprising, per liter:
  • 1.5 moles of hydrochloric acid,
  • 0.2 mole of nitric acid,
  • 0.2 mole of phosphoric acid,
  • 0.1 g salicylic acid.

Les conditions opératoires furent les suivantes :

  • · volume du bain : 970 cm³,
  • · aire de la surface soumise au polissage : 87,3 cm²,
  • · température : 45°C,
  • · durée de l'immersion : 3 heures.
The operating conditions were as follows:
  • Bath volume: 970 cm³,
  • · Surface area subject to polishing: 87.3 cm²,
  • Temperature: 45 ° C,
  • · Duration of the immersion: 3 hours.

On a relevé les résultats suivants :

  • · profondeur d'attaque : 29 µm,
  • · rugosité moyenne arithmétique :
    • · avant le polissage : 0,26 µm,
    • · après le polissage : 0,23 µm,
  • · brillance : 7 %.
The following results were noted:
  • Attack depth: 29 µm,
  • Arithmetic mean roughness:
    • · Before polishing: 0.26 µm,
    • · After polishing: 0.23 µm,
  • Gloss: 7%.

Exemple 11Example 11

On a mis en oeuvre un bain de polissage comprenant, par litre :

  • · 1,5 mole d'acide chlorhydrique,
  • · 0,2 mole d'acide nitrique,
  • · 0,2 mole d'acide phosphorique,
  • · 0,1 g d'acide salicylique,
  • · 0,005 mole d'acide perchlorique.
A polishing bath was used comprising, per liter:
  • 1.5 moles of hydrochloric acid,
  • 0.2 mole of nitric acid,
  • 0.2 mole of phosphoric acid,
  • 0.1 g salicylic acid,
  • 0.005 mole of perchloric acid.

Les conditions opératoires furent les suivantes :

  • · volume du bain : 970 cm³,
  • · aire de la surface soumise au polissage : 87,3 cm²,
  • · température : 45°C,
  • · durée de l'immersion : 3 heures
The operating conditions were as follows:
  • Bath volume: 970 cm³,
  • · Surface area subject to polishing: 87.3 cm²,
  • Temperature: 45 ° C,
  • · Duration of the immersion: 3 hours

On a relevé les résultats suivants :

  • · profondeur d'attaque : 31,2 µm,
  • · rugosité moyenne arithmétique :
    • · avant le polissage : 0,24 µm,
    • · après le polissage : 0,22 µm,
  • · brillance : 8 %.
The following results were noted:
  • Attack depth: 31.2 µm,
  • Arithmetic mean roughness:
    • · Before polishing: 0.24 µm,
    • · After polishing: 0.22 µm,
  • Gloss: 8%.

Une comparaison des résultats obtenus aux exemples 1 à 9 avec ceux obtenus aux exemples 10 et 11 fait apparaître le progrès apporté par l'invention, pour ce qui concerne la rugosité et la brillance obtenues à l'issue du polissage.A comparison of the results obtained in Examples 1 to 9 with those obtained in Examples 10 and 11 shows the progress made by the invention, with regard to the roughness and the gloss obtained after polishing.

Claims (13)

Bains pour le polissage chimique de surfaces en acier inoxydable, comprenant, en solution aqueuse, un mélange d'acide chlorhydrique, d'acide nitrique et d'acide phosphorique, et un acide hydroxybenzoïque éventuellement substitué, caractérisés en ce qu'ils comprennent, dans la solution aqueuse, une amine hydrosoluble.Baths for the chemical polishing of stainless steel surfaces, comprising, in aqueous solution, a mixture of hydrochloric acid, nitric acid and phosphoric acid, and an optionally substituted hydroxybenzoic acid, characterized in that they include, in the aqueous solution, a water-soluble amine. Bains selon la revendication 1, caractérisés en ce que l'amine comprend plus de 10 atomes de carbone dans sa molécule.Baths according to claim 1, characterized in that the amine comprises more than 10 carbon atoms in its molecule. Bains selon la revendication 2, caractérisés en ce que le nombre d'atomes de carbone de l'amine est compris entre 11 et 20.Baths according to claim 2, characterized in that the number of carbon atoms in the amine is between 11 and 20. Bains selon la revendication 3, caractérisés en ce que l'amine est une amine primaire comprenant entre 12 et 18 atomes de carbone.Baths according to claim 3, characterized in that the amine is a primary amine comprising between 12 and 18 carbon atoms. Bains selon l'une quelconque des revendications 1 à 4, caractérisés en ce que l'amine est présente dans la solution aqueuse en une quantité comprise entre 1 et 1000 mg par litre de solution.Baths according to any one of claims 1 to 4, characterized in that the amine is present in the aqueous solution in an amount between 1 and 1000 mg per liter of solution. Bains selon l'une quelconque des revendications 1 à 5, caractérisés en ce qu'ils sont exempts d'ions ferricyanure et d'ions ferrocyanure.Baths according to any one of Claims 1 to 5, characterized in that they are free from ferricyanide ions and ferrocyanide ions. Bains selon l'une quelconque des revendications 1 à 6, caractérisés en ce qu'ils comprennent, dans la solution aqueuse, un additif sélectionné parmi l'acide perchlorique et les sels hydrosolubles de l'acide perchlorique.Baths according to any one of Claims 1 to 6, characterized in that they comprise, in the aqueous solution, an additive selected from perchloric acid and the water-soluble salts of perchloric acid. Bains selon l'une quelconque des revendications 1 à 7, caractérisés en ce qu'ils comprennent, dans la solution aqueuse, un additif capable de décomposer l'acide nitreux.Baths according to any one of claims 1 to 7, characterized in that they comprise, in the aqueous solution, an additive capable of breaking down nitrous acid. Bains selon la revendication 8, caractérisés en ce que l'additif capable de décomposer l'acide nitreux est sélectionné parmi l'urée et les dérivés de l'urée.Baths according to claim 8, characterized in that the additive capable of breaking down nitrous acid is selected from urea and urea derivatives. Bains selon l'une quelconque des revendications 1 à 9, caractérisés en ce qu'ils comprennent, par litre de solution aqueuse, · entre 0,5 et 5 moles d'acide chlorhydrique, · entre 0,005 et 1 mole d'acide nitrique, · entre 0,005 et 1 mole d'acide phosphorique, · entre 0,001 et 5 g d'acide hydroxybenzoïque, · entre 0,001 et 1 g d'amine, · entre 0 et 0,5 mole de l'additif sélectionné parmi l'acide perchlorique et les sels hydrosolubles de l'acide perchlorique, · entre 0 et 0,500 g de l'additif capable de décomposer l'acide nitreux. Baths according to any one of Claims 1 to 9, characterized in that they comprise, per liter of aqueous solution, Between 0.5 and 5 moles of hydrochloric acid, Between 0.005 and 1 mole of nitric acid, Between 0.005 and 1 mole of phosphoric acid, Between 0.001 and 5 g of hydroxybenzoic acid, Between 0.001 and 1 g of amine, Between 0 and 0.5 mole of the additive selected from perchloric acid and the water-soluble salts of perchloric acid, · Between 0 and 0.500 g of the additive capable of breaking down nitrous acid. Bains selon l'une quelconque des revendications 1 à 10, pour le polissage chimique des surfaces en acier austénitique.Baths according to any one of Claims 1 to 10, for the chemical polishing of austenitic steel surfaces. Procédé pour le polissage d'une surface en acier inoxydable, selon lequel on met la surface en contact avec un bain de polissage chimique, caractérisé en ce qu'on met en oeuvre un bain conforme à l'une quelconque des revendications 1 à 11.Method for polishing a stainless steel surface, according to which the surface is brought into contact with a chemical polishing bath, characterized in that a bath according to any one of Claims 1 to 11 is used. Procédé selon la revendication 11, caractérisé en ce qu'on règle la température du bain entre 20 et 65°C.Process according to Claim 11, characterized in that the temperature of the bath is adjusted between 20 and 65 ° C.
EP91201422A 1990-06-19 1991-06-10 Baths and process for chemical polishing stainless steel surfaces Expired - Lifetime EP0462646B1 (en)

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BE9000625A BE1004452A3 (en) 1990-06-19 1990-06-19 Baths and method for chemically polishing stainless steel surfaces.
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US7118685B1 (en) * 1999-07-13 2006-10-10 Kao Corporation Polishing liquid composition
JP4578661B2 (en) * 2000-09-28 2010-11-10 日本表面化学株式会社 Chemical polishing solution for gold and gold alloy
CN102703937A (en) * 2012-05-24 2012-10-03 北京工业大学 Polishing process for stainless steel base tape for coated conductor
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
CN102888609A (en) * 2012-10-26 2013-01-23 南京大地冷冻食品有限公司 Stainless steel chemical polishing liquid
CN103422092B (en) * 2013-07-19 2015-12-02 吴江骏达电梯部件有限公司 A kind of polishing fluid and finishing method thereof
CN103642398B (en) * 2013-11-28 2015-07-22 上海航天精密机械研究所 Polishing liquid for stainless steel material and use thereof
US10428429B2 (en) * 2014-09-30 2019-10-01 Agency For Science, Technology And Research Formulation and method for inhibiting carbon-based deposits
CN104498870A (en) * 2014-12-11 2015-04-08 沈阳富创精密设备有限公司 Aluminum plating pretreatment process of multi-arc ion plating of threaded stainless steel part and application
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HU209843B (en) 1994-11-28
BG60922B1 (en) 1996-06-28
US5209820A (en) 1993-05-11
PL168604B1 (en) 1996-03-29
YU47856B (en) 1996-02-19
DE69102947D1 (en) 1994-08-25
YU104991A (en) 1994-04-05
ATE108838T1 (en) 1994-08-15
PT97999A (en) 1992-03-31
JPH04231483A (en) 1992-08-20
CN1057494A (en) 1992-01-01
CS184191A3 (en) 1992-02-19
RU2086700C1 (en) 1997-08-10
EP0462646B1 (en) 1994-07-20
HU912030D0 (en) 1991-12-30
HUT61608A (en) 1993-01-28
CA2044113A1 (en) 1991-12-20
DE69102947T2 (en) 1995-02-23
ES2060286T3 (en) 1994-11-16
CZ280639B6 (en) 1996-03-13
MY106562A (en) 1995-06-30
BG94644A (en) 1993-12-24
BE1004452A3 (en) 1992-11-24
BR9102496A (en) 1992-01-21

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