BE889231A - PROCESS FOR TREATING METAL OBJECTS - Google Patents

PROCESS FOR TREATING METAL OBJECTS Download PDF

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Publication number
BE889231A
BE889231A BE6/47477A BE6047477A BE889231A BE 889231 A BE889231 A BE 889231A BE 6/47477 A BE6/47477 A BE 6/47477A BE 6047477 A BE6047477 A BE 6047477A BE 889231 A BE889231 A BE 889231A
Authority
BE
Belgium
Prior art keywords
emi
formic acid
metal objects
treating metal
water
Prior art date
Application number
BE6/47477A
Other languages
French (fr)
Original Assignee
Centre Rech Metallurgique
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 Centre Rech Metallurgique filed Critical Centre Rech Metallurgique
Priority to BE6/47477A priority Critical patent/BE889231A/en
Publication of BE889231A publication Critical patent/BE889231A/en

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
    • C23G5/00Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents

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

       

  CENTRE DE RECHERCHES METALLURGIQUES -

  
 <EMI ID=1.1> 

  
Association sans but lucratif -

  
Vereniging zonder winstoogmerk

  
à BRUXELLES, ( Be lgique) .

  
 <EMI ID=2.1> 

  
La présente invention se rapporte à un procédé de traitement

  
des objets métalliques. Il est applicable de façon particulièrement intéressante aux tôles en acier pour carrosserie d'automobile, notamment pour les décaper.

  
Il est bien connu que dans de nombreux traitements de matériaux métalliques et spécialement de tôles d'acier, on plonge

  
ces matériaux dans une solution aqueuse d'un produit approprié,

  
par exemple un acide minéral ou organique, tel que de l'acide formique, pour obtenir sur la surface du dit matériau l'une

  
ou l'autre propriété considérée comme avantageuse. L'efficacité du traitement est évidemment fonction de la nature chimique des corps en présence, de la température, de leurs concentrations, de la durée de l'opération, etc... 

  
Il est fréquent, surtout lorsque la solution considérée est

  
à température relativement élavée. que se forme une phase vapeur en équilibre avec la phase liquide que l'on s'applique

  
 <EMI ID=3.1> 

  
cette phase étant considérée comme inutilisable.

  
Prenant le contrepied de ces idées, l'inventeur a découvert que, de façon tout à fait inattendue, il était possible, dans le cas de l'acide formique, grâce à 1*existence d'un point azéotropique pour lequel la valeur de la température d'ébullition n'est que faiblement supérieure aux températures d'ébullition des constituants purs, de faire usage d'un décapant à l'état de vapeur.

  
On a constaté que le diagramme d'équilibre vapeur - liquide de l'eau et de l'acide formique était tel que du côté des fortes teneurs en eau du mélange eau - acide formique, il existait un certain pouvoir décapant de la phase vapeur, pouvoir déjà sensible au niveau d'une concentration de 5 ppm d'acide formique, à laquelle correspond une température de vapeur de mélange pratiquement égale à 100[deg.]C.

  
Partant de cette constatation, l'inventeur a imaginé de mettre en contact un courant de vapeur d'eau avec de l'acide formique et de projeter sur un objet métallique à décaper, un jet de gaz constitué de, ou contenant en majeure partie, la phase vapeur "eau - acide formique" ainsi obtenue.

  
 <EMI ID=4.1> 

  
à partir d'un générateur de vapeur d'eau sous pressi.on et d'un réservoir contenant de l'acide formique fournissant la phase vapeur désirée à un dispositif de projection appropriée, ajutage - gicleur - pistolet...

  
Les applications de ce procédé apparaissent assez importantes,

  
 <EMI ID=5.1>  

  
 <EMI ID=6.1> 

  
formique ont un prix de revient faible;
- sur une tôle ne présentant pratiquement pas d'oxyde, une telle projection assure une protection temporaire de la tôle, car l'acide formique ne forme que des composés non hygroscopiques. Une telle protection n'exige donc plus de huilage des tôles, ce qui est notamment fort intéressant pour les fûtiers ?
- sur une tôle oxydée sur les deux faces et destinée à être galvanisée sur une seule face. : 
- on traite d'abord la face qui doit être galvanisée,
- on traite ensuite l'autre face au moyen du mélange vapeur <EMI ID=7.1> 
- sur une tôle peu ou pas oxydée et devant être galvanisée sur une seule face :

   
- on oxyde volontairement la face qui ne doit pas être galvanisée,
- on galvanise l'autre face et on retraite ensuite la première face de la façon indiqué plus haut,
- sur pièces métalliques de forme quelconque, spécialement les pièces creuses :
- on peut tout d'abord, si nécessaire, les déshuiler par un procédé approprié, thermique ou chimique,
- traiter ensuite les pièces par projection de la vapeur "eau - acide formique". On obtient ainsi une protection temporaire des dites pièces sans agent gênant de protec-

  
 <EMI ID=8.1>  

  
Revendications.

  
 <EMI ID=9.1>  aur les dites taies un gaz constitué de ou contenant en majeure partie, une phase gazeuse -eau - acide fornique-.



  METALLURGICAL RESEARCH CENTER -

  
 <EMI ID = 1.1>

  
Nonprofit organization -

  
Vereniging zonder winstoogmerk

  
in BRUXELLES, (Belgium).

  
 <EMI ID = 2.1>

  
The present invention relates to a method of treatment

  
metallic objects. It is particularly advantageous for steel sheets for automobile bodywork, in particular for stripping them.

  
It is well known that in many treatments of metallic materials and especially of steel sheets, one plunges

  
these materials in an aqueous solution of a suitable product,

  
for example a mineral or organic acid, such as formic acid, to obtain on the surface of said material one

  
or the other property considered advantageous. The effectiveness of the treatment is obviously a function of the chemical nature of the bodies present, the temperature, their concentrations, the duration of the operation, etc.

  
It is common, especially when the solution considered is

  
at relatively washed out temperature. that a vapor phase is formed in equilibrium with the liquid phase that is applied

  
 <EMI ID = 3.1>

  
this phase being considered unusable.

  
Taking the opposite view of these ideas, the inventor discovered that, quite unexpectedly, it was possible, in the case of formic acid, thanks to the existence of an azeotropic point for which the value of the boiling temperature is only slightly higher than the boiling temperatures of the pure constituents, to make use of a stripper in the vapor state.

  
It was found that the vapor-liquid equilibrium diagram of water and formic acid was such that on the side of the high water contents of the water-formic acid mixture, there was a certain pickling power of the vapor phase, power already sensitive at the level of a concentration of 5 ppm of formic acid, to which corresponds a temperature of vapor of mixture practically equal to 100 [deg.] C.

  
On the basis of this observation, the inventor imagined bringing a stream of water vapor into contact with formic acid and projecting onto a metallic object to be stripped, a gas jet consisting of, or containing for the most part, the vapor phase "water - formic acid" thus obtained.

  
 <EMI ID = 4.1>

  
from a pressurized steam generator and a tank containing formic acid supplying the desired vapor phase to an appropriate spraying device, nozzle - nozzle - gun ...

  
The applications of this process appear to be quite important,

  
 <EMI ID = 5.1>

  
 <EMI ID = 6.1>

  
formics have a low cost price;
- On a sheet having practically no oxide, such a projection provides temporary protection of the sheet, since formic acid only forms non-hygroscopic compounds. Such protection therefore no longer requires oiling of the sheets, which is particularly advantageous for the barrel-keepers?
- on an oxidized sheet on both sides and intended to be galvanized on one side. :
- we first treat the side which must be galvanized,
- the other side is then treated using the steam mixture <EMI ID = 7.1>
- on a sheet with little or no oxidization and having to be galvanized on one side:

   
- the face is voluntarily oxidized which must not be galvanized,
- the other side is galvanized and then the first side is retreated as indicated above,
- on metal parts of any shape, especially hollow parts:
- firstly, if necessary, they can be de-oiled by an appropriate thermal or chemical process,
- then treat the parts by spraying the steam "water - formic acid". Temporary protection of the said parts is thus obtained without any annoying protective agent.

  
 <EMI ID = 8.1>

  
Claims.

  
 <EMI ID = 9.1> on the said pillowcases a gas consisting of or containing for the most part, a gaseous phase - water - fornic acid -.


    

Claims (1)

2. Procédé suivant la revendication 1, caractérisé en ce que <EMI ID=10.1> 2. Method according to claim 1, characterized in that <EMI ID = 10.1> sous pression dans un réservoir contenant de l'acide formique et en recueillant la phase gazeuse qui s'en échappe. under pressure in a tank containing formic acid and collecting the gas phase which escapes therefrom. <EMI ID=11.1>  <EMI ID = 11.1>
BE6/47477A 1981-06-15 1981-06-15 PROCESS FOR TREATING METAL OBJECTS BE889231A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
BE6/47477A BE889231A (en) 1981-06-15 1981-06-15 PROCESS FOR TREATING METAL OBJECTS

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
BE889231 1981-06-15
BE6/47477A BE889231A (en) 1981-06-15 1981-06-15 PROCESS FOR TREATING METAL OBJECTS

Publications (1)

Publication Number Publication Date
BE889231A true BE889231A (en) 1981-10-01

Family

ID=25659634

Family Applications (1)

Application Number Title Priority Date Filing Date
BE6/47477A BE889231A (en) 1981-06-15 1981-06-15 PROCESS FOR TREATING METAL OBJECTS

Country Status (1)

Country Link
BE (1) BE889231A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0094808A1 (en) * 1982-05-14 1983-11-23 Uss Engineers And Consultants, Inc. Method of box-annealing steel sheet to minimize annealing stickers

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0094808A1 (en) * 1982-05-14 1983-11-23 Uss Engineers And Consultants, Inc. Method of box-annealing steel sheet to minimize annealing stickers

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Legal Events

Date Code Title Description
RE Patent lapsed

Owner name: CENTRE DE RECHERCHES METALLURGIQUES - CENTRUM VOO

Effective date: 19860630