DE669520C - Process for preventing wires, sheets or strips, especially those made from heavy metals, from sticking together during bright annealing - Google Patents

Description

Method of preventing wires, sheets or plates from sticking together Strip, especially made of heavy metals, bright annealing, bright wires and sheets easily bake together when glowing by keeping their surfaces at the glowing temperature weld together.

To prevent caking, it is recommended for trays that are stacked It is known that the individual sheets are annealed with an oxide skin before annealing which act as a separating layer during annealing and prevent baking together target. In order to form this oxide skin, it is indicated, for example, that the metal sheets are in front immersed in an aqueous chromate solution before glowing.

Bright annealing is more difficult with wires than with sheet metal because the wires are more heavily contaminated with oil or grease residues from being pulled When the annealing material is heated, reducing gases form. These gases reduce at higher temperatures the metal oxides. For example, copper oxide is already used Temperatures far below the recrystallization temperature of copper and its Alloys reduced to metallic copper, so that a protective layer of oxides on wires made of copper and copper alloys at the annealing temperatures no longer can be effective.

In order to be able to properly anneal bare wires, one must therefore use the Wires apply a coating, also in thin layers, which gives the bare appearance of the wires do not affect the annealing temperatures by hydrogen and Hydrocarbons are not attacked. These properties own the sulphides of heavy metals in particular. According to the invention one provides hence the bare wires with a thin coating of the sulfide, des to glowing metal.

The coating is advantageous by chemical action on the wire surface self-generated when glowing. To this; Purposes are set according to a further suggestion of the invention when pulling the wires of the drawing liquor emulsified from water and oil At least a water-soluble sulfur compound for the last drawing process to, which has the property at your annealing temperatures or already during heating split off a gaseous sulfur compound from the material to be annealed, like sulfur dioxide and reducing hydrogen sulfide from the metal of the wire surface to form sulfide will.

Such water-soluble sulfur compounds are the sulfides of the alkalis, for example sodium sulfide. But it is particularly advantageous if you use the drawing liquor an organic sulfur compound such as piperidine pentamethylene dithiocarbamate is added.

The above-mentioned additives to the drawing liquor result in an operation, namely the dipping of the annealing material before the annealing is saved. The applied according to the invention However, auxiliaries are just as effective when they are used as special in aqueous solution Immersion bath used.

The method according to the invention is not limited in its application to the bright annealing of wires, but also with advantage in the bright annealing of metal volumes '' and sheets are applicable. One can _dis * er. or sheets for this purpose from. Dip the annealing into a solution of the auxiliary used according to the invention. or add this agent, for example as described above for wires, to the lubricating fluid for the final mechanical processing.

Claims (2)

PATENT CLAIMS: i. Method of Preventing Caking of Wires, strips or sheets, in particular made of heavy metals, during bright annealing, characterized in that the bare objects before annealing with a thin Sulfide layer are coated. 2. The method according to claim i, characterized in that that the objects are lubricated with a water-oil emulsion during the last drawing process which contains a water-soluble sulfur compound that reacts on glowing the surface of the objects with the metal forms a sulphide coating.