DE2103368A1 - Process for coating steel parts with enamel - Google Patents

Description

M I E L E Ä C I E

483 Güt.rtloh OlflOOCO

Ceri-Mi »! E-SiraQe - Telephone 881 £ IUJODO

"Process for coating steel parts with enamel"

The invention relates to a method for direct enamelling of steel parts.

The disadvantage of the known direct enamelling is that inadequate decarburized steel or defects in the surface during immersion enamelling appear.

In addition, with enamelling it is known that already from the steel manufacturer For enamelling pre-treated steel parts, a Zn coating is applied as transport protection.

However, this Zn layer had to be removed before enamelling, since it was generally assumed that this Zn layer perfect enamelling is not possible. However, this subsequent removal of the Zn coating is expensive and requires an additional one Operation.

The object of the invention is to avoid these known disadvantages and to disclose a method for coating steel parts with enamel, in which when enamelling insufficiently decarburized steel or when enamelling rope no more significant errors occur. In addition, it should be avoided that serving as transport protection Zn coating must be removed before enamelling. j

For this purpose the invention is characterized in that the steel parts are coated with a Zn layer of 0.3 to 5 g / m surface can be coated.

Another feature of the invention is that it is available from the steel manufacturer For enamelling pretreated steel parts, the Zn layer also serves as transport protection.

209835/0181

IW I t L t & U I t

483 Ciri-Mlele-StraB goods flea - Telephone 881

-2- 21Q3368

So far, this Zn coating, which serves as a transport protection, has been removed before enamelling, since it was generally assumed that this Zn coating interferes with enamelling. Tests have shown, however, that with a Zn layer of 0.3 to 5 g / m ² surface, the quality of the direct enamelling is improved.

Is the door treatment for direct enamelling already at the steel manufacturer carried out and the surface has been provided with a Zn coating of 0.3 to 5 g / m surface as transport protection, see above This reduces the 7or treatment process for direct enamelling in the further processing plant to a degreasing and degreasing process Rinse cycle and possibly a drying cycle.

With direct enamelling as well as with conventional enamelling Different application methods are used, e.g. diving.

Dipping direct emails is relatively unproblematic as long as the email is dark in color, such as black, dark blue or brown. With light-colored emails, such as white emails, you quickly get dark spots in the email surface. This phenomenon comes about as follows conditions:

When the objects are immersed in the slip, they are pretreated by the Surface rubbed off individual particles, which either mix with the slip or in the form of a thin layer swim on the bath surface. In the first case, the fine particles are in the layer applied by dipping, in the second In the case, the fine particles lay on the surface of the just enamelled part when they are pulled out of the immersion tank. In both In some cases, errors occur during the burn-in process, furthermore, the entire contents of the immersion tank can pass through the fine Particles are changed in color, so that the enamel in the dip tank becomes unusable.

2 0 9 83 § / 01 8 1

MIELE & CIE

483 Giitersioh

Carl-Miele-Strasse. Telephone 881 Ttnoooo

- 3 - I \ UJODO

The new process offers the following "advantages:

1) Lower plant and processing costs because of the Zn coating no longer needs to be removed.

2) After enamelling, the goods do not need to be dried immediately because the Zn layer discolors the applied Enamel layer prevents

3) The storage side of the pretreated goods is increased because the Zn layer covers the pretreated steel surface and the influence of the atmosphere is suppressed. i

4) The surface quality is improved since before enamelling relatively smooth and abrasion-resistant surfaces are present.

5) Decarburization defects of the steel are suppressed and thus black points or so-called "pinholes" on the enamelled Surface avoided.

6) There is no discoloration of the slip during dip enamelling because the Zn coating makes the workpieces wear-resistant Own surface. In addition, both the Zn coating and the zinc oxide and zinc hydroxide are practically white. j

209835/0181 - 4 -

Claims (2)

Patent claims: Method of coating steel parts with Eaail, thereby characterized in that the steel parts gate the birette enamelling With a Zn coating τοη 0.3 to 5 g / a surface coated will. 2) Method for coating τοη steel parts with Small according to Claim 1, characterized in that when ready tob steel manufacturers have pre-treated steel parts for enamelling, the Zn coating also serves as transport protection. 209835/01 8 1