DE1965586B2 - STEEL SHEETS, WHICH ARE PROVIDED WITH A COATING, IN PARTICULAR AN ENAMEL LAYER, AFTER A SHAPING, PROCESS FOR THEIR PRODUCTION AND USE OF THE STEEL SHEETS - Google Patents

Description

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The steel according to the invention are advantageously metallized vanically or chemically or with plastic

Sheets are used in the enamelling technology and coatings are provided here,

particularly efficient in single-layer enamelling, for polyphosphates which are used for the

the specially pretreated metal surfaces necessary steel sheets and the inventive method in

are dig. 5 question are salts of phosphoric acids with

The steel sheets to be deformed are given the general formula HO [HOPO ₂ ] _m H, where η

partly degreased directly after production, an integer of at least 10, preferably over

pickled and provided with a nickel layer. The upper 100, means. The hydrogen is by monovalent

Surface treatment is carried out using cations known per se, such as Na ⁺ , IC ⁺ , Li ⁺ , NH ₄ ⁺ , or substituted ones

Process, either purely chemically or fully electrolytically, replacing ammonium ions, with polyphosphates being used

or by a combination of chemical or electronic one type of ion, but also with different ions

trolytic steps. For example, an electro can be used. For reasons of solubility in

Lytically degreased, electrolytically pickled and electro-polar, preferably aqueous media are used in

Lytically nickel-plated sheet metal by connecting a high molecular weight polyphosphoric acid preferably

alkaline coarse degreasing. 15 mixed salts, such as B. Na / K salts are used.

The order of the pretreatment steps would be the same for the preparation of the invention

in this case look like this: Polyphosphate solutions used in steel sheets are

A11 1 u ^ ι. j ^ produced by processes known per se.

Alkaline coarse degreasing, _{one usually thinks of} pdyphosphates like

Electrolytic fine degreasing, _{ao Kurolls} ⁶ _chen * _Salzeil) Madrell salts or Graham

^ ^p , ^un f '. . _o . salt out and swap, if not enough

Electronic stain, water solubility is present, part of the

apu ung cations are characterized by different types of cations. Man

Electrolytic nickel plating _{can be added to the insoluble K-} curollate in Wasger

rinse, suspend _ag [KPO ₃ J _n in water and add

J drying. _from Q _{5 to 6 parts of a} sodium phosphate such. B.

The advantage of the electrolytic pretreatment of a sodium polyphosphate [NaP0 ₃ ] _m or compared to the purely chemical method lies in a phosphate Na ₄ P ₂ O ₇ , Na ₆ P ₃ O ₁₀ , (NaPO ^ (Na-tri-shortening of the total residence time by about 65%. In the metaphosphate (NaPOg) ₆ (Na-hexametaphosphate) connection the water-soluble polyphosphate 30 or also Na ₃ PO _{4 is brought} into solution,
z. B. applied by immersion or spraying. It is also possible to disperse the potassium polyphosphate in the whole treatment, including the sheet water, and to carry it out fully continuously with the aid of sodium production. The sheet metal provided with the ion exchangers containing a part of the cover layer can then be exchanged for potassium ions for sodium ions, so rolling, pressing, drawing or other non-cutting 35 that a soluble Na / K polyphosphate is obtained,
deform lifting methods. Following the course it is possible, numerous other salts deformation, the cover before the enamelling of monovalent cations with polyphosphates of Zuabgezogen or washed with water, no composition [KP0 _{3] n} or [NaPO _3] "implement that deterioration the surfaces prepared for the enamelling, whereby the polymer molecules also take place after the exchange. 40 of some of the cations are still due to foreign cations

Surprisingly, it was found that the can be insoluble, which in most cases indicates

Cover from the present invention to be used the presence of foreign ions in the supernatant

Polyphosphates are based on sheet metal forming as a lubricating solution. By decanting and adding

medium works, especially if organic auxiliaries were available. Salt-free water then generally occurs

can be added, and that even if the solution is insufficient. For the method according to the invention

If there is a complete lack of removal prior to enamelling, the low-salt or low-salt can be used

no impairment of the enamel adhesion and enamel solutions that generally have higher viscosities

surface is to be determined. and also the polyphosphate containing foreign salts

This results in the interesting possibility of using solutions.

The presses can also work fat-free and so a 50 It is possible by adding organic sub-after-treatment to bypass completely. In the punching with high or low molecular weights In practice, such a mode of operation does not always result in properties of the polyphosphate protective layers be possible because of the pollution caused by the affect. Additions of water-soluble polymer enamelling interfering substances can hardly be avoided sowing seeds with medium to low molecular weights is. After all, it is very advantageous that even with a 55 can exert a softening effect that is overly incomplete Removal of the protective layer to make a train pliable, elastic and smooth as well flawless enamelling is guaranteed. the deformation of the sheet metal has a lubricating effect

The method according to the invention is not based on email. By adding low molecular weight substances

method, but can also be used, for example, to reduce the dissolving speed

Similar technical fields are used, 60 speed of the protective coatings when removing the same

where deformed metallic objects are then to be increased enamelling.

ßend be provided with a protective layer, especially as substances that are primarily physical especially when good adhesion of the protective properties of the protective layers such as strength, layer a carefully cleaned surface, given elasticity, sliding ability, etc. affect if necessary, a specially pretreated substrate 65 is also mentioned, for example: polyethylene oxide or polyn necessary is. As already stated, the glycol ether, polypropylene glycol, polyvinyl alcohol, drive advantages, e.g. B. also in the production of metal polyvinyl ethers, polyvinyl pyrrolidone, polyacrylamides, Lischer objects that after deformation gal- polyacrylates, modified maleic anhydride copoly-

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merisate with ζ. B. styrene, isobutylene, etc., water-soluble pretreated sheet with a 0.35% aqueous borne polyester, etc. and mixtures of such water-K / Na polyphosphate solution in the spray process soluble polymers and corresponding copolymers. The coating was now deformed. According to the molar weight of the added sheet metal with the help of a fat-free tool and organic polymers, the films are melted and finally a direct enamelling with a B-Tidigcr and softer (low molar weights of the poly white enamel of the following composition:
additions) or the properties of the ^ go / cjq
i lhf

) ^ g / jq

Protective layers in the direction of the film properties 0 5 V Al O

of the organic polymer (high molar 21 'V B O *

weight of the polymer additives). 10 _J5 £) alkali oxide

Substances that also have the physical properties 2 y fluorine

shafts of the protective layers, but primarily the | p y j-.q

The re-dissolving of the protective layers are influenced by 0 5V MeO

mainly those that have a surface-active agent

like nonionic, anionic or 15/025

cationic emulsifiers. From this group of substances without prior removal of the polyphosphate

may be mentioned, for example: polyglycol ether, coating.

Settlement products from phenols or alcohols with

Ethyl oxide, fatty acid salts, sorbitan esters, sulfonates, burn at 82O ⁰ C a very good enamel adhesion and

such as B. Alkylbenzenesulfonate, sulfuric acid half esters so enamel surface.

of long-term alcohols, etc. The rate of dissolution The polyphosphate solution was obtained by reacting

digkcit is of course also obtained by adding oligo- of (KP0 ₃ ) »with NaCl in a molar ratio of 1: 3,

kidneys or polymers with low molecular weights by using a suspension of (KP0 ₃ ) _M in water

elevated. The additions of organic substances, NaCl (1: 3) was added, after 1 hour of stirring

attracted to the polyphosphate, can in principle be separated from the swollen precipitate and converted into pure

accept loving relationships. Was dissolved when organic water was added.

The molecular weight of the polyphosphate is achieved by the polymer or plasticizer

desired effects in general for quantities _Λ,. , ..... Ιηψ .. · ■ -. _v

between 1 and 75%, while the emulsifiers partly- viscos.tatswert - ^ - printed out, c = concentra-

are wisely effective in very small amounts; d. H. in 30 tion in g / 100 ml solvent.

Concentration ranges between 0.01 and 10%, b _w bczogen nH-_ ₃₀ Bestimmune _{in wat, 2} 5 ° C at the polyphosphate. It is a matter of course - c ~ ^{JU determination in water} «<- ^at P ^H

Loan possible, organic polymers and compounds value 7, concentration 0.05% in presence

of emulsifier types to be used together. That of 0.1% NaCl at τ = 0.98 dynes / cm ² .

Polyphosphates and the organic additives can 35 The polyphosphate contains 7.5% potassium

applied separately, with a through and 13.1% sodium,

mixture by diffusion in the applied. .

Solution layers can occur. Advantageously, for example

However, if the solutions are mixed beforehand, the A steel sheet of the analysis given above is

carrying polyphosphates and organic additives 40 alkaline pre-degreased, electrolytically fine degreased, sets. When using mixtures of polyphosphates rinses electrolytically in a solution of 150 g and organic substances, small _{amounts of Na 2} SO ₄ · 10 H ₂ O / 1 and 5 ml H ₂ SO ₄ conc./l can also be used with a large amount of anti-aging agents or stabilizers Pickled for a current density of 10 A / dm ^{2 for} 1 minute, rinsed the organic substances are added. and finally in a solution of

The coatings with the 45 g «vfjcQ · 7 HO / l
The substances can be determined according to 10e NH Cl / 1 ²

Methods are applied, e.g. B. sprayed on, 20 g MgSO ■ 7 HO / l

dipped, painted on, etc. For application particularly 5 ε H BO / 1 ^%

thinner films are preferably sprayed with an S 3 3 /

Aqueous or, if appropriate, organic solution 50 at current densities of 0.5 A / dm ² runs on the substrate for 1 minute and the solvent evaporates. nods.

The method according to the invention is described below

explained in more detail using examples. with a 0.35% aqueous K / Na polyphosphate

". -Ii solution coated by dipping and after done

Example _g5 7 _ΓΟ0 ΐς _Π11Γ ^ of a standard in enamelling works

A cold-rolled sheet is subjected to the shape analysis on a hydraulic press.

Q = 0 004! / After the deformation, the protective layer was through

Mn = 0 * 320y spraying with H ₂ O removed, the part dried and

S = 0035 ° / then with a B-Ti white enamel of the above

P = 0040 ° / ^6o composition direct white enamelled. Both liability

Si = 0020 / ^a ' ^{s also the enamel} surface were excellent. It

Cu = 0027 / became the same polyphosphate solution as in Example 1

' used.

was degreased alkaline, rinsed warm and cold, example 3

Pickled 6 minutes in 9% H ₂ SO ₄ at 75 ° C, rinsed, 65 ^p

6 minutes in 1/2% NiSO ₄ · 7 H ₂ O solution for a steel sheet of the above analysis

7O ⁰ C and pH 3 nickel, rinsed and finally treated as in Example. 1 The pretreated neutralized. The finished sheet was then treated with a 2% aqueous K / Na poly

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phosphate solution, the 6% K / Na hexametaphosphate. Direct white enamelling with a followed

contained as foreign salt, coated by brushing. B-Ti white enamel of the above composition. As well as

After the applied layer had dried, both adhesion and the enamel surface were determined.

the sheet metal is deformed as is usual in the enamelling factory.

subject to change. Then the poly was 5 Example 7
remove the phosphate layer by spraying it off with water.

far away. Thereafter, the deformed sheet was three thin sheets with the designation A, B and C of the above analysis with a B-Ti white enamel of the above composition were enamelled in the example 2 direct white. Both adhesion and pre-treated in the manner described in the enamel. Panel A was awarded with no surface. The polyphosphate polymer protective layer in the enamelling plant was formed into a solution by stirring [KPO ₃ J _n with the cover plate of an electric cooker. The (NaPO ₃ J ₆ (1: 3) obtained in water. Viscosity formed sheet A was directly white enameled with a B-Ti white enamel Ιηψ _ Q j of the above composition. Sufi '' probably the adhesion and the enamel surface were very good

Example 4 ^{> 5 bad}

Sheet B was deformed in the same way as sheet A,

A steel sheet of the above analysis, however, then hosed down with water,

was pretreated as in Example 1. The pre-The direct white enamelling with the B-Ti white

The plate was delivered with a 2% aqueous email of the above composition

K / Na polyphosphate solution, the 5% polyethylene glycol ao adhesion and enamel surface poor results.

(M. G. 1000) contained as a plasticizer, by spraying sheet C was before deforming with a

coated. After the applied 2% K / Na polyphosphate solution has dried (see Example 3),

Layer was the sheet in the enamelling plant containing 1.5% nonylphenol polyglycol ether through

subject to severe deformation. Syringes were then coated. After the poly-

the polymer coating by brushing under the layer of fluid became sheet C - like the sheets

removed from the water. A direct white followed - A and B - deformed. Then the poly-

enamelling with a B-Ti white enamel of the above phosphate layer by spraying off with water.

composition. Both liability and enamel over- all. Subsequently, the deformed sheet C

area were excellent. It was the same with the B-Ti enamel of the above composition directly

K / Na polyphosphate solution as used in Example 3. 30 white enameled. Both liability and email

_Ώ . ·, - surface were - in contrast to the sheets A

^{B e! s} P ^{l e} ' ⁵ and B - excellent.

A steel sheet of the above analysis was made. .

pretreated as in Example 2. The pretreated example 8

The sheet was treated with a 2% aqueous K / Na poly. A steel sheet of the analysis given above

phosphate solution, the 6% K / Na hexametaphosphate alkaline degreased, rinsed warm and cold, 3 minutes

as a foreign salt and 8% polyvinyl ethyl ether (MW 1500) in 9% H ₂ SO ₄ at 20 ⁰ C pickled, rinsed, in a

as a plasticizer, coated by spraying. Solution of 200 g CuSO ₄ · 7 H _a O / l and 70 g U ₂ SOJl

After the applied layer had dried, electrolytic treatment was carried out at 30 ° C. with 4 A / dm ^{2 for 10 minutes}

the sheet metal in the enamelling factory a strong deformation 40 copper-plated and rinsed. Then the

subject. Subsequently, the poly sheet was in a 2% aqueous solution of K / Na-

phosphate layer removed by spraying with water. Polyphosphate coated and dried. After

The subsequent direct white enamelling with a deformation was the polymer layer only with

B-Ti white enamel of the above composition delivered rinsed in water,
Excellent in terms of adhesion and enamel surface

nice results. The polyphosphate solution corresponded to example y

the solution used in Example 3. A steel sheet of the above analysis was made

. , electrolytically degreased, rinsed, 3 minutes in 9%

^{B e l r l e l} ° H ₂ SO ₄ pickled at 20 ° C, rinsed, in a solution

A steel sheet of the above analysis was 50 von

pretreated as in Example 1. The pretreated 320 g zinc sulfate / l,

Sheet was with a 2% aqueous K / Na-Poly- 30 g ammonium chloride / l,

phosphate solution containing 0.8% oleic acid oxethane sulfonate 20 g magnesium sulfate / l and

■ contained, covered with the help of two rubber rollers. 15 g sodium acetate / 1
After the applied layer had dried, 55

• the sheet is pressed in the enamelling factory to form a cover plate at pH 4.0 and 30 ⁰ C with 10 A / dm ^{2 for} 9 minutes of a commercially available electric cooker. long electrolytically galvanized and rinsed. The polymer layer was then subsequently removed through the metal sheet in a 2% strength aqueous solution by spraying with water. It could observed K / Na-polyphosphate coated at 6O ⁰ C and become that this coating dries very quickly through 60th After the deformation the polymer washes has to be removed. layer just rinsed off with water.

209 540/391

Claims (8)

1 2 pretreated, d. H. so z. B. a corresponding claims: pickling process with subsequent nickel plating before takes. The adhesion base achieved in this way for the 1. With a removable cover layer white enamelling must then of course before Steel sheets, which if necessary an additional 5 deformation are protected in such a way that none have metallic intermediate layer and damage to the applied layer occurs. A not subject to machining deformation such protection is achieved with already known and then with a firmly adhering protective tape pretreatment process through an electrolyte layer, in particular an enamel layer, provided with a zinc layer applied to the table. are characterized by an io The disadvantage of such a metallic protective Removable cover made of water-soluble poly-layer is involved in the complicated aftertreatment, phosphates. which forces the enamelling factory to be one of several 2. Process for the production of steel sheets Steps to erect existing plant (degreasing, according to claim 1, characterized in that rinsing, pickling of the protective layer with acid, e.g. B. on the steel sheets following a treatment in hydrochloric acid, rinsing, neutralizing). In the same way, it is more rational to use metallic surfaces act the removable cover with the help of a material obtained by drawing, pressing, pickling or solution containing water-soluble polyphosphates other non-cutting machining is applied to the and that then brought a firmly adhering desired shape and then subsequently with Protective layer, in particular an enamel layer, in a firmly adhering metallic or non-metallic layer is applied in a known manner. Layer are provided, immediately following their 3. The method according to claim 2, characterized marked production of degreasing and pickling and then characterized in that the removable cover is made with a surface-protecting, but easy to aqueous solution to be provided as a water-removing cover. Also coatings of soluble polyphosphates, the sodium, potassium, 35 from metal, which are electrodeposited or chemically deposited lithium, ammonium and / or substituted am, or baking enamels, dip enamels and other monium salts of polyphosphoric acids of the general plastic coatings require one as far as possible my formula HO [HOPO ₂ ] »H, where η is a pure background to provide permanent protection to the whole number of at least 10. Ensure surfaces. The task of 4. The method according to any one of claims 2 and 3, 30 workers of metals for the subsequent Bedieß characterized in that the removable coating can be used as directly as possible Supplying material made with an aqueous solution is therefore not limited to enamelling, which, as water-soluble polyphosphates, limits their industry. Contains mixed sodium and potassium salts. The advantages are many; next to a material 5. The method according to any one of claims 2 to 4, 35 savings due to the omission of an additional ent characterized in that the removable rust or removal of other corrosion layers Coverage with an aqueous solution is the stain and the associated work-up which, in addition to the water-soluble polyphosphate, of the wastewater in large plants becomes more economical need to carry out additional water-soluble polymers with soft. contains action. 40 From the German Auslegeschrift 1 192 487 is a 6. The method according to any one of claims 2 to 5, the method has become known, according to which to achieve characterized in that the removable or improving the corrosion resistance of Cover with an aqueous solution made of metals or alloys this becomes with a tannin, which are treated in addition to the water-soluble phosphating solution containing polyphosphate, th additional water-soluble polymers with film- 45 The coatings formed in this way remain contains forming properties. however on the metal and can 7. The method according to any one of claims 2 to 6, layering, especially in direct white enamelling, characterized in that the removable Ab- lead to considerable difficulties. Coverage produced with an aqueous solution. The present invention is now will, in addition to the water-soluble polyphosphates !! 50 steel with a removable cover also contains emulsifiers. sheet metal, possibly an additional metallic 8. Use of water-soluble Polyphos intermediate layer and one not chipphate for the coating of steel sheets, which are subjected to lifting deformation and then the deformation can be enamelled. with a firmly adhering protective layer, especially 55 special an enamel layer, and which are characterized by the fact that they are a removable cover made of water-soluble poly- The direct white enamelling of sheet steel is possessed in phosphates. In recent years, the present invention has also become a reliable production object Procedure. By streamlining the 60 a method of making the ones described above Production process and introduction of continuous steel sheets, which is characterized in that programmed manufacturing methods became one on the steel sheets following one in well-known Consistent quality of the enamelled products, the way in which the surface treatment is carried out associated with a reduction in enamelling- removable cover with HiUe a water-soluble one cost, achieved. A further simplification of the Ar- 65 polyphosphate-containing solution is applied and in the enamelling plant is given by the fact that a firmly adhering protective layer, in particular that the special layer of enamel used to manufacture the raw parts is applied in a known manner. The strip is already brought to the steelworks for single-layer enamelling.