FR2623212A1 - POST-PROCESSING SOLUTION OF A PLATED STEEL SHEET FOR WELDING, AND METHOD FOR ITS APPLICATION - Google Patents

Abstract

The invention relates to the coating of an electroplated steel sheet with a post-treatment solution, in a thickness of 0.02 to 2 mum. Said solution, having a pH of 3 to 10, contains 2 to 100 g / l of at least one water-soluble or water-dispersible material, and may contain 0.01 to 3 g / l of Cr ** 6 ion. ** & I1 A and / or 10 to 100 g / l of an organic amine soap. Application: post-treatment of a plated steel sheet intended for welding.

Description

2 2623212

  The present invention relates to the after-treatment of a welded steel sheet for welding and, particularly, the post-treatment solution which has a wettability and adhesion to the weld, hereinafter referred to as suitability welding, as well as corrosion resistance,

  excellent workability and durability.

  Recently, Sn-plated steel sheets, Pb-Sn-plated steel sheets, Cu-plated steel sheets or Zn-plated steel sheets have been used as plated steel sheets suitable for welding. However, these plated steel sheets corrode easily without post-treatment during packaging or after assembly. As a result, said steel sheets are subjected to post-treatments, such as treatment with a

  chromate, a phosphate treatment or a coating

  with an anti-corrosive paint.

  In the case of a chromate treatment, the latter is not suitable because an amount greater than 0.1 m7g / dm2 of Cr6 is necessary to achieve sufficient corrosion resistance. However, in the case of an amount greater than 0.05 mg / dm 2+ Cr, a strong flux is required for the solder. The use of a strong fluxing agent causes a deterioration of the working environment and decreases the corrosion resistance of the welded surface. As a result, the amount of Cr6 + is limited to less than 0.05 mg / dm 2 and does not confer resistance

sufficient for corrosion.

  On the other hand, the application of an anti-corrosive paint causes a decrease of aptitude

  welding similar to that caused by a

  by a chromate and also a decrease

  the corrosion resistance of the welded spot.

  There is some prior art concerning

  a process for the production of a flat steel sheet

  for welding; for example, the patent application

  Japanese public inspection N Sho. 61-

  19793 and the Japanese patent application being inspected

  N0 Sho. 54-15432. However, the present invention differs from these inventions with respect to the construction and materials used. Japanese Patent Application Laid-open N Sho. 61-19793 relates to a plated steel sheet

  having excellent welding ability, which is

  in the following manner: Sn or an alloy of

  Sn-Pb is deposited by plating onto the sheet steel

  Zn or with a Zn-type alloy, the quantity

  deposition being between 0.1 and 100 g / m2. How-

  In fact, Sn is so expensive that the production cost is high and the use of Pb is undesirable from the point of view of environmental pollution. The present invention differs from this invention in

  concerning construction and materials used

  Sees. On the other hand, Japanese Patent Application Laid-open N Sho. 54-15432 concerns

  a post-treatment which is summarized as follows

  vante: a Zn-plated steel sheet is covered with an acrylic resin in a thickness of 0.5 to 20 gm or a paraffinic wax in a thickness of 2 to

  lm. The present invention differs from this invention

  with regard to the materials used and the effects on weldability and resistance

to corrosion.

  The electroplated steel sheet is coated with a post-treatment solution in a dry thickness in the range of 0.02 to 2 μm. The post-processing solution contains 2 to

  100 g / l of at least one water-soluble material or

  Perseus in water, such as: a. fatty alcohols, b. alkylphenols, c. condensation products prepared from fatty acids and ethylene oxides, d. polyethylene glycol alkylamines,

  e. esters prepared from sorbite

  tan and fatty acids, f. surfactants prepared from polypropylene glycols (as hydrophobic group) and polyethylene glycols (as hydrophilic group), g. amides prepared from fatty acids and diethanolamines, h. esters prepared from fatty acids and sucrose, and i. saponification products prepared from an alcohol derived from lanolin or from acids

fatty derived from lanolin.

  Alternatively, 2 to 100 g / l of a water-soluble or water-dispersed, halogen-free solder flux may be used, such as: a. abietic acid, b. benzoic acid, c. saturated fatty acids having 12 to 24 carbon atoms, d. unsaturated fatty acids having 12 to 24 carbon atoms, e. organic alcohols having 2 to 400 carbon atoms, f. esters of fatty acids, g. benzotriazole and metalate derivatives, ammonium salts and amine salts

of these materials.

  In addition, it is possible to use 5 to 200 g / l

phosphoric esters.

  A quantity of 0.01 to 3 g / l of Cr6 + and / or

  10 to 100 g / l of an organic amine soap

  that may also be present.

  The detailed process according to the present invention is described below: The main constituents of the present invention are:

  a .. water-soluble fatty alcohols or

  persecuted in water, b. alkylphenols, c. condensation products prepared from fatty acids and ethylene oxides, such as polyethylene glycol alkyl phenyl ether, polyethylene glycol alkyl ether and polyethylene glycol fatty acid esters, d. polyethylene glycol alkylamines, such as N-polyethylene glycolalkylamine and a polyethylene glycol alkyl ether,

  e. esters prepared from sorbite

  tan and fatty acid, comprising an acid ester

  sorbitan fat and a fatty acid ester of poly-

  ethylene glycol sorbitan. f. surfactants prepared from polypropylene glycol (as hydrophobic group) and polyethylene glycol (as hydrophilic group),

  like polypropylene glycol-polyethylene ether

  glycol, g. amides prepared from a fatty acid and diethanolamines, such as diethanolamides of fatty acids, h. esters prepared from acids

  fatty acids and sucrose, such as sucrose

  fatty acids, and i. saponification products prepared from an alcohol derived from lanolin or from a lanolin-derived fatty acid, such as a lanolin-derived polyoxyethylene alcohol ester and polyoxyethylene fatty acid esters derived from lanolin .

  As a welding flux with no halogen

  gene, we can mention: a. abietic acid, b. benzoic acid, c. saturated fatty acids having 12 to 24 carbon atoms, such as stearic acid, lauric acid, palmitic acid, d. unsaturated fatty acids having 12 to 24 carbon atoms, such as oleic acid,

  e. organic alcohols, such as glycerol

  cerol, ethylene glycol and a polyethylene glycol having 4 to 400 carbon atoms, f. esters of fatty acids, such as esters of fatty acids, glycerol, g. benzotriazole derivatives, such as

  benzotriazole, azimidole, 1-N-benzoylbenzoate

triazole.

6 2623212

  Phosphoric esters include

  soaps formed with organic amines or mono-

  acids or di-acids with one or two alkyl groups.

  If the alkyl group is bulky and is not soluble in water, it is. t possible to add

  ethylene oxide or neutralize

  with an alkaline agent to improve

  hydrophilic property. These phosphoric esters may be used preferably in an amount of from 5 to 200 g / l, and at least one

of these is used.

  The effects of the present invention are

  controlled by the amount of post-coating

  treatment on the plated plate, and are not

  by the concentration of the post-solution

  treatment. However, a specific concentration is preferred to facilitate the operation. An ion

  halogen is not appreciated. because it decreases the resistance

corrosion.

  In order to stabilize the post-

  treatment and to improve resistance to corrosion

  and abrasion resistance, Cr6 + and / or a soap of an organic amine are used. Co6 concentration of Cr6 greater than 3 g / l decreases considerably

  welding ability and is not suitable for this purpose.

  Soaps of organic amines include

  soaps formed with dodecylamine, oleoyl

  imidazoline, an aminopropylamine derived from beef tallow, an amine derived from rosin. The amine can be used in the form of a salt formed with carbon dioxide. An amine concentration greater than 100 g / l has some effects on corrosion resistance, but a smaller effect on

  welding ability, and is not appreciated.

  In addition, water-soluble or water-dispersible, well-known anti-corrosive agents are available but in this case it is important to limit the amount added so as not to reduce the weldability. For example, the addition of an acrylic emulsion increases the abrasion resistance

  but decreases inversely proportionally

the welding ability.

  The pH value of the solution is suitable

  The pH of the solution is less than 3, the stability of the solution decreases. If the pH of the solution is

  greater than 10, the post-drying properties of

treatment decreases.

  The post-treatment temperature is not limited; however, at a temperature above 80 ° C, the stability of the aftertreatment solution decreases, resulting in gelation. A usual temperature in the meantime

  from 20 to 40 C is suitable and economical.

  The coating process is not limited and a roll coating, a coating to the blade,

  immersion followed by treatment with

  or by air knife are used. The product obtained by post-treatment must be sufficiently dry to

can be manipulated.

  A dry film thickness included in

  the range of 0.01 to 2 μm is suitable. A thick

  dry film less than 0.01 pm does not have any

  effect on corrosion resistance. At a thick

  dry film greater than 2 gm, resistance

  corrosion increases, but not the weldability.

  In the present invention, the post-treatment solution 6+, which may further contain Cr6 + or organic amine soap, may be applied to Sn plating, Pb-Sn plating, Cu plating or plating of Zn. The weldability and the corrosion resistance of said steel sheets increase, even after aging. The steel sheets are not limited to said steel sheet. The reason why the properties of the coated steel sheet of the present invention are improved has not been elucidated. However, the formation of oxides, hydroxides and carbonates is inhibited by coating said plated steel sheet

  by the post-treatment solution of the invention.

  Furthermore, it is considered that since the post-treatment makes it possible to dissolve or reduce the metal oxides which have formed on the plated steel sheet over time, wetting and diffusion of the solder are accelerated and the suitability welding is improved. Following this phenomenon, the

  post-processing film of the invention covers a single

  sheet steel and increases the resistance

corrosion.

  The present invention is based on the concept mentioned above. By uniformly coating

  the sheet steel clad with the post-solution

  treatment of the invention, a plated steel sheet having weldability and resistance

  excellent corrosion can be produced in

  tinu. Particular embodiments of the present invention are as follows:

EXAMPLE 1

  A cold rolled steel sheet having a thickness of 0.5 mm was used as a substrate and was treated by a usual alkaline cleaning and pickling. After spraying with water, the substrates were electroplated in a sulfuric acid bath at the weight of 5 g / m 2 of zinc layer and treated according to the present invention. In this respect, steel sheet

  plated with Zn was coated with a post-solution

  treatment containing 10 g / l of ammonium stearate, g / l of glycerol and 5 g / l of paraffin wax. by

  an immersion process, and the steel sheet thus

  The pick was dried at 60 C to form

  on it a coating of 0.5 Vm thick.

  Examples 2 to 17 of the present invention

  were treated according to the same procedure as in Example 1, except for the type of

  and the amount of layer and post-treatment.

COMPARATIVE EXAMPLE I

  The same substrates as in Example I were treated by a usual alkaline cleaning and pickling. After spraying with water, the substrate was subjected to electroplating in a sulfuric acid bath, to the weight of 10 g / m 2 of zinc layer and electroplated in a bath of phenolsulfonic acid (40.degree. 30A / dm2) in accordance with the Japanese patent application

  to the public inspection N Sho. 61-19793.

  Comparative Example 2 was carried out in accordance with Japanese Patent Application Laid-open N Sho. 54-15432. Comparative Examples 3 to 12 were carried out according to the same procedure as that of Comparative Example 2, except for the type and amount of the layer and post-treatment. The post-treatment conditions were summarized in Table I and the property evaluation was summarized on

Table II.

  As mentioned in Table II, the post-treatment solution of the present invention exhibited excellent effects on corrosion resistance, weldability, and aging tests. Conventional chemical treatments, such as chromate treatment or phosphate treatment (Comparative Examples 3-5), had effects on corrosion resistance, but decreased the wettability of the weld. In addition, the color of the surface after aging

  varied and decreased the corrosion resistance.

  Comparative Examples 6-8, in

  The phosphates or Cr6 esters of Examples 6-8 were deficient in having excellent weldability, but lower effects on corrosion resistance and weldability.

after aging.

  Comparative Examples 6-8, which contain

  halogen in the fondants intended for

  had excellent corrosion resistance

  slow but lower effects on fitness

  welding after aging compared to

treatment of the invention.

  As mentioned in Examples 1-17, in Tables I and II, excellent corrosion resistance, weldability and workability were obtained and these properties, after aging of a plated steel sheet, can

  be achieved by implementing this invention.

  tion. Evaluation: The metal substrates that were prepared in Examples 1-17 and Comparative Examples 1-12 were evaluated using the following test methods. The results are

  presented in Tables I and II.

  (1) Suitability for spreading the weld: a sample of sheet steel was floated;

1 21

  having a size of 50 x 50 mm, on the solder bath at a temperature of 250 C. The quantity of 0.4 g of folded solder wire, that is, solder filled with resin-based flux (JIS Z 3283), was placed on the sheet steel sample for seconds. The spreading weld surface was measured

after cooling.

  O: soldering surface spread> 200 mm2 A: 200 m2 5 soldering surface> 50 mm2 X: soldering surface spread 50 mm2

  (2) Resistance by matching the sou-

  lasts: a packet of twenty threads (4 = 0.18 mm) was placed

  on the test steel sheet and secured with the flux-filled flux-filled (HR) weld and subjected to a tear-off test (the package of twenty copper wires and the sheet metal). steel bearing the weld were subjected to traction in opposite directions and the appearance of the place of the

separation was evaluated.

  O: no separation between the wire, the

  welding and welded steel sheet.

  X: separation between the wire and the weld, or between the weld and the sheet

welded steel.

  (3) Resistance to corrosion: an exchange

  steel sheet was subjected to two cycles of a salt spray test (JIS Z 2371: salt spray for 8 hours and drying for 16 hours) and rust production

red has been evaluated.

O: no red rust -

  : presence of red rust on the whole

  (4) Shaping ability: Erichsen test (Er = 7 mm) and Du Pont impact test (12.7 rrm x 1) kg x 30 cm) and have been evaluated for suitability

  swimming by means of the test using adhesive tape.

  : no separation between the plated steel sheet and the post-treatment layer

  X: separation between sheet steel

  and the post-processing layer.

  (5) Aging: Steel sheet samples were placed in a thermo-hygrostat (60 C, 95% RH) for 1000 hours and evaluated for

  concerning the appearance (or the variation of color-

  corrosion resistance and weldability, in the same way

(1) - (4).

  It goes without saying that the present invention

  described only as an explanatory but not limita-

  tif, and that many modifications can be made

  made without departing from its scope.

TABLE I

  Preparation and Condition of Samples Example Type of Plating Amount of Post-Treatment Solution of Deposit Thickness (g / m 2) The Present Invention (g / l) (Pm) 1 Plated with Zn 5 Ammonium Stearate 10 Glycerol 20 0.5 Paraffin wax 5 2 Zn-plated 10 Benzotriazole derivative 2 Phosphoric ester-amine ester salt 1 0.05 CrO3 0.2 3 Sn-plated 5 Oleic acid 50 Phosphoric ester 10 3 4 Cu-plated 3 Ester prepared from of fatty acid and glycerol 0.2 Paraffinic wax 10 Sn-Pb plated Ethylene glycol 30

CrO3 1 1.

  6 Zn-plated 5 alkylphenyl polyphenyl ether

  ethylene glycol (Emaruzitto-16: Daiichikogyo Seiyaku Co.LTD) 0.5 CrO3 1

  7 Plated Zn 10 Polypropylene Glycol Ether

  polyethylene glycol (Epan-720: Daiichikogyo Seiyaku Co.LTD) 100 0.5 Phosphoric ester 5

  8 Sn-plated 2 Oleic polyethylene ester - -

  glycol (Noigen-ES90: Daiichikogyo Seiyaku Co.LTD) 2 2 _ __._ _. CrO3 0.02 TABLE I (Continued) Preparation and Condition of Samples Example Type of Plating Amount of Post-Treatment Solution of Deposit Thickness (g / m 2) The Present Invention (g / l) (Pm) 9 Sn-Plated 5 Stearate of polyethylene glycol (Noniolite-T40: Kyoueisya Yushi Co.LTD) 0.02 Phosphoric ester 1

  Cu-plated 3 Sorbitan Oleate (Noniolite-

  SPS: Kyoueisya Yushi Co.LTD) 50. 0.2 CrO3 1

  11 Sn-Pb Plated Polyoxyethylene-alkylpropylene

  diamine (Noniolite-DNT-10: Kyoueisya Yushi Co.LTD) 0.5 CrO3 1

  12 Zn-plated 5 Phosphoric Ester (monobasic)

  ) 100 2 ____ CrO3 0.02 13 Zn-plated 10 Phosphoric ester (mixed mono- and di-basic) 200 0.5 14 Sn-plated 2 Phosphoric ester 5 CrO3 3 0.01 Rosin (amine salt ) Sn-plated 5 Mono (dioleyl) phosphoric ester (amine salt) 10 0.1 oh -_______ ____ _ _ CrO3 0.2 o ffi Lq ............... TABLE I (Continued) Preparation and Condition of Samples Plating Type Amount of Post-Treatment Solution Thickness xample Deposition (g / m 2) The Present Invention (g / l) (Pm) 16 Cu Plated 3 Phosphoric Ester 50 Dodecylamine 100 0 Sn-Pb Plated 10 Phosphoric Ester (alkanolamine ________ salt) 150 0.2 Example Sn Plated (as requested)

  compa- Japanese Zn 10 Plated N Sho 61-

ratif 1 19793) 0.5 ---

  2 Zn-plated 10 Paraffinic wax (according to Japanese patent application N Sho 54-15432) 100 3 3 Sn-plated 5 Treatment with phosphate 2 g / m 2 as P 4 Sn-plated 5 Treatment with chromate 0, 0.5 mg / dm 2 as Cu-plated Cr 3 Chromate treatment 0.05 mg / dm 2 as Cr 6 Zn-plated 5 As in Example 6, except ___._.__.__. CrO3 0.5 rrN TABLE I (Continued) Preparation and Condition of Samples Plating Type Amount of Post-Treatment Solution of Deposit Thickness (g / m 2) The Present Invention (g / l) (Pm) 7 Zn Plated 10 As in Example 7, except the phosphoric ester 28 Sn-plated 2 As in Example 8, except CrO3 0.02 9 Zn-plated 5 Aniline hydrochloride immersion (1 second) Zn-plated 10 Benzotriazole of Example 2 replaced by Hydrazinium Hydrochloride 0.02 Zinc-plated Zn 2 Paraffinic wax replaced by 0.05 mg / dm Sn (IV) chloride in the form of Cr 12 Zn-plated 10 ' TABLE II Evaluation of characteristics

  N Resistance Welding Ability Change Ability

  of the ability to withstand the corrosion-resistant behavior of the stagnation of the stagnation Example 1 0 0

2 o 1o o o.

43 0 0 O0 0 0

4 .. 0 '0' 0 00

1 0 0 0 1 0_ _

  6 0 0 0 0 0 0 0 7 1 I 1 o o 1 1 0. 1 o o o o o o o o o o o o o o o o o o o o

11 1 0 0 0O 0

12 0 0 00 O

Example i

comparative

13 0 0 (D 0 0O

_ _ _ o o _ _ 0

1 3 0_ 0 .. A 0 0O

14 x 0 O * o x O _ _ _

1 6 O 0 O X

1 7 0 0 D 0 0 0

  Comparative Example O | E-O 4 A-O.i O -O 0 82

0 To J A 00 - X

3 J A I 'I 0 /% I y -0

8 J X 0 J. 0 O 0 /%

  I x o: I o oC TABLE II (Continued) No. ResistanceAbility to WeldingChange Ability

  from the sample-to the aptitude at lessee-i fashioned of colora-

  corrosion corrosion and stagnation

. . ..

Comparative Example I 9I

9 X I O O O X

  X I o IoX 11x 1D I I O x 1 2 X] 0 l O___O_

0 '! V V X Z.

0 1 I I X

o X, _____ I

 0 I 'x x I -

  o V-x V-X X o | J | J | V j o 0 x x v 0 | X | X V 1 7ed o 10 iX_ o 11 I o 1

0 X X O

O O 0 0 L O O

o 10 k0 9 1

0 | O | O | 0

  O - OX O O i O I 0. 'I -O, I I o t o Jo H tols

O 0 1 0 8

o o o 0 0 0 At

O0 O O O01 _ _

0 C) 0 0

o Jo 10 9 *

0 1 0 0 -

o 0 10 o t

0 O 0 O

O 0 O I O -O O I

0 O0 0

0 O 0 I a-dma

e2vuuo e; di-

0l

  apnQTpdf | aSepnos denies apnlTçdV azue: sTsa-.

  O2 (O) OL (ap apa -9ssTITTaTA spadQ senbTisTgDauzD sap UoTIEnIetA III fLy

ZLZ-Z9Z

2623212

* TABLE III (Continued).

  Evaluation of the characteristics after an aging of 1000 hours N Resistancj Suitability for welding Ability _ _ _ _ _ _ _ _ _ - au à à l'I'hance à l'aptitude à Resistance sillon corrosion l'étalement tance i _ _ _ ,, ,

Example

comparative X 0

X O 0

11 X O

Claims (3)

  1. A method of post-treatment of a plated steel sheet for welding, characterized in that it consists in coating the plated steel plate with a post-treatment solution in an amount corresponding to a thickness of dry state of 0.01 to 2 μm, said post-treatment solution containing 2 to 200 g / l of at least one water soluble or dispersed material comprising: a. fatty alcohols, b. alkylphenols, c. condensation products prepared from fatty acids and ethylene oxides, d. polyethylene glycol alkylamines, e. esters prepared from sorbitan and fatty acids, f. surfactants prepared from polypropylene glycol as the hydrophobic group and polyethylene glycol as the hydrophilic group, g. amides prepared from a fatty acid and diethanolamine, h. esters prepared from fatty acids and sucrose, i. saponification products prepared from an alcohol derived from lanolin or from a fatty acid derived from lanolin, j. abietic acid, k. Benzoic acid, 1. saturated fatty acids having 12 to 24 carbon atoms, m. unsaturated fatty acids having 12 to 24 carbon atoms, n. organic alcohols having 2 to 400 carbon atoms, o. esters of fatty acids, e.g. benzotriazole and metalate derivatives, ammonium salts and amine salts of said materials, q. a phosphoric ester, and the pH of said solution of   post-processing having a value in the range of 3 to 10.   2. Process according to claim 1, characterized in that   the post-treatment solution contains 0.01 to 3 g / l of Cr6 +.   3. Process according to claim 1, characterized in that the post-treatment solution additionally contains 10 to 100 g / l of a organic amine soap.