Classic black oxidation products, as used for steel or iron materials, cannot be used to colour stainless steel materials. Our special products are aimed at:
a) Non-magnetic stainless steels Brün VA
b) Magnetic stainless steels Brün VA-OS 4020
A special working process, similar to classic steel black oxidation, must be used. Applicable technical and safety engineering requirements must also be complied with. Before stainless steel materials are coloured, they must be free of grease and clean. We recommend our Alkalit products as a suitable degreasing product. With some surfaces, we recommend they are first activated by suitable acidic pickling agents. Special pickling agents based on hydrochloric acid are the choice here.
The type of material and the prior mechanical processing can have a great influence on the colour result. We think it best to select the products to be used on the basis of the known data and to carry out a sample treatment before processing large surface volumes where possible. Brün VA is a powder-based special black oxidation salt. An appropriate quantity is carefully dissolved in water, mix thoroughly and then heated. It is suitable for uniform blackening of high alloy and stainless steels, preferably for non-magnetic stainless steels. An immersion process is used.
Brün VA generates uniform, deep black surfaces. Compound parts that also include steel components can also be black oxidised. The layer is resistant to bending and wear. Conductivity and magnetic properties are not affected. If Brün VA does not provide the required result for magnetic stainless steel materials, we recommend that you use our product Brün VA OS 4020 for these materials.
Brün VA OS 4020 is a highly alkaline, powder-based product. An appropriate quantity is carefully dissolved in water, mix thoroughly and then heated. This forms an oxidic-sulphidic coating. Brün VA OS 4020 is particularly suitable for blackening of V2A materials, i.e. magnetic stainless steels, generating uniform, deep black surfaces. If Brün VA OS 4020 does not provide the required result for non-magnetic stainless steel materials, we recommend that you use our product Brün VA for these materials. An immersion process is used. Dimensional tolerances are retained and the layer is resistant to bending and wear. Conductivity and magnetic properties are not affected.