LU81061A1 - GALVANIZATION PROCESS - Google Patents

Description

8'4 Λ λ A BL-2603 / EM / mg J-Π Q | j GRAND-DUCHY OF LUXEMBOURG Patent N * ____________________________________ of —---------------- Minister, jJtÂSb of the National Economy and the Middle Classes

Title issued: _________________________________

Industrial Property Service

~ Ûi ~ n LUXEMBOURG

y / A * '^ / {/ j <fo Patent Application I. Application CENTER Dg RESEARCHES METALLURGIOUES-CENTRÜM VOOR RESEARCH IN ^ METALLURGIE, associai ^^ non-profit-vereniging zonder winstoog- mërlif, "4'7rueltoin ^ .....................................

represented by MMïEvîSeyers and E; TïFreyiinger> iiig; consven propr. (ïnd · 4 6 r rue -dU "" Gimetière / biixe! abourgr'39i & sant - en - qualité · de-mandataires deposit ........ ce nineteen £ ... mrs „.. mll .... new ..... Genfc ..... BoixmterMx-Muf ..... (3> to ......... 1.6.Ä..QQ .. hours, at the Ministry of National Economy and the Middle Classes, in Luxembourg: ♦ 1. this request for obtaining a patent of invention concerning: v ..... .................................................. .................................................. .................................................. ............... w .................................. .................................................. .................................................. .................................................. .................................................. ............................................. (5) 2. Paul, ..... André COSSE, ..... 150 VoiE de Liège. 4501 Bellalre, Belgium___ 2. the delegation of power, dated ......._______ ________________ the —_____________________ 3. description in language ............. f £ AU.9.äi.Se _______________________________ of the invention in two copies; 4 ........... / ................... drawing boards, in two copies; 5. the receipt of the fees paid to the Luxembourg Registration Office, on March nineteen one thousand nine hundred and seventy-nine _______________________________________________ claims for the above patent application the priority of one (s) application (s) of ( 6) ______________ L ............................................... ........................ filed in (7) .................. ..................... J_______________________________________________________________________ on ------------- L ------------- ---------------------------------------------------------- ---------------------------------------------------------- ---------------------------------------------------------- ---------------------------------------------------------- ---------------- (8) in the name of —L .------------------------- ---------------------------------------------------------- ---------------------------------------------------------- ---------------------------------------------------------- -------------------------------------- (9) elect domicile for him / her and, if designated, for its representative, in Luxembourg ____________________________________ 46r rue du Cimetière ....................................... .................................................. .................................................. .. (io) requests the grant of a patent for the invention for the subject described and represented in the abovementioned appendices, - with postponement of this grant to .......... î · ..®. ...........................month.

\ LÎ jJn / feg proxies' ^ Ernest Möjerpf "" II. Deposit Minutes

The above application for a patent for invention has been filed with the Ministry of National Economy and the Middle Classes, Industrial Property Service in Luxembourg, dated: 19.3.1979 j ^. The Minister at 16 · OO hours of the National Economy and the Middle Classes, r «,, .................. ûm% 7

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', *! BL-2603 I C 1946/7903.

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I * PATENT OF INVENTION

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it METALLURGICAL RESEARCH CENTER - || CENTRUM VOOR RESEARCH IN DE METALLURGIE, i jj Non-profit association - Vereniging zonder winstoogmerk il in BRUXELLES, (Belgium).

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il -—— - ij Galvanizing process.

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i | The present invention relates to a process'). for galvanizing metallic objects.

i | He has been known for a long time to protect? j metallic surfaces with grease-based coatings or. j of zinc alloys.

The classic galvanizing technique consists of immersing the metal object to be galvanized in a bath of zinc or zinc alloys, and this after a certain number of treatments: i

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2.- preliminary (pickling, rinsing, fluxing, ...) so as to give the surfaces to be treated the properties which will ensure a good quality galvanized coating.

The conventional galvanizing bath contains 0.1 to 1.5% of Pb and is generally composed of zinc with commercial purity corresponding to AFNOR NFA 55101 standards of April 1955, classes Z6 and Z7.

Zinc Z7 thus contains 0.15% Cd, 0.02% Fe and 0.002% Cu as tolerated impurities.

The actual galvanization is generally preceded by degreasing operations, pickling by immersion in hydrochloric acid containing a corrosion inhibitor, and by fluxing or depositing a layer of a flux of the zinc chloride type and ammonium.

The zinc coating is considered to be correct if the appearance is smooth, relatively shiny, obviously adherent, and if the thickness is around 70 to 100 microns.

However, it has been found that conventional dip galvanizing, as described above, gives poor results with steels containing more than 0.01% Si, and this is the case with many steels of construction.

The zinc coatings appear grayed out, an indication of the formation of fragile intermetallic compounds, of an abnormal thickness (200 to 300 microns and more) and of poor adhesion both because of the thickness of the coatings and of their brittleness.

The solutions proposed to the problems relating to the application of hot dip galvanizing of steel! containing more than 0.01% Si # are essentially based on the addition of a number of elements to the galvanizing bath.

The process of the invention uses a galvanizing bath which makes it possible to obtain galvanized coatings j not having the serious defects mentioned above, during 3 $ - ♦ 3.- of its use in the galvanization of steels containing silicon.

The process is based on studies of the influence of certain elements selected and added in adequate proportions to the galvanizing bath.

The process which is the subject of the present invention, comprising a galvanizing bath which contains at least 70% by weight of zinc, is characterized in that one or more of the following elements are added to the galvanizing bath: chromium, nickel , boron, titanium, vanadium, zirconium, manganese, copper, niobium, cerium, molybdenum, cobalt, antimony, calcium, lithium, sodium, potassium, and in such quantity as the content of the bath during its use, in each element taken in isolation, ie less than 2% by weight.

One embodiment of the process of the invention consists in limiting the lead content of the above-mentioned galvanizing bath to 2% by weight at most.

Another embodiment of the process consists in limiting the aluminum content of the galvanizing bath to 2.5% by weight at most.

A third embodiment of the process of the invention provides for the presence of 2.5% by weight at most of magnesium in the galvanizing bath.

A fourth embodiment of the process of the invention provides for the presence of a maximum of 3% by weight of tin in the galvanizing bath.

A preferred embodiment of the process of the invention comprises a galvanizing bath which contains at least 76% by weight of zinc, less than 2% by weight of lead, aluminum and magnefcium, both at less than 0.5% by weight and from 0.01 to 3% by weight of tin and is characterized in that one or more of the following elements are added to the above-mentioned galvanizing bath: chromium, nickel, boron, titanium,

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4.- v · / vanadium, zirconium, manganese, copper, niobium, cerium, molybdenum, cobalt, antimony, calcium, lithium, sodium, potassium and this in quantity such as the content of the bath during its use, in each element taken in isolation, ie less than 1% by weight.

The aforementioned addition elements will preferably be added in the form of alloys, however it is not excluded to include them in the bath in the pure state.

The above description has as a preferred field of application, soaking galvanization, however, it is obvious that the composition of the galvanizing bath can also be used in other processes such as continuous galvanization, by spraying. spray, vapor deposition, electrolytic deposition, etc.

Claims (5)

1. Galvanizing process, comprising a galvanizing bath which contains at least 70% by weight of zinc, characterized in that one or more of the following elements are added to the above-mentioned galvanizing bath: chromium, nickel, boron, titanium , vanadium, zirconium, manganese, copper, niobium, cerium, molybdenum, cobalt, antimony, calcium, lithium, sodium, potassium, in an amount such as the content of the bath during its use, in each element taken in isolation, either less than 2% by weight. 2. Method according to claim 1, characterized in that the lead content of the galvanizing bath is at most, equal to 2% by weight. 3. Method according to claims 1 or 2, characterized in that the aluminum content of the galvanizing bath is less than 2.5% by weight. 4. Method according to claims 1 or 2 and / or 3, characterized in that the magnesium content of the galvanizing bath is less than 2.5% by weight. 5. Method according to claims 1 or 2 and / or 3 and / or 4, characterized in that the tin content of the galvanizing bath * is less than 3% by weight. 5. Method according to claim 1 / characterized in that the galvanizing bath contains at least 76 weight of zinc, less than 2% by weight of lead, aluminum 6.- i * and magnesium, both less than 0.5% by weight and 0.01 to 3% by weight of tin and in that one or more of the following elements are added to the above-mentioned galvanization bath: chromium, nickel, boron, titanium, vanadium, zirconium, manganese, copper, niobium, cerium, molybdenum, cobalt, antimony, calcium, lithium, sodium, potassium, and in an amount such as the content of the bath during its use, in each element taken in isolation, either less than 1% by weight. ί> H <