DE1003166B - Process for bright drawing of non-ferrous metal semi-finished products, e.g. B. tape, and lubricant to carry out the process - Google Patents

Description

GERMAN

The invention relates to the preferably continuous cold drawing of non-ferrous metals in elongated shape, e.g. B. of strips, bars, wire, tubes, in which the cross-section of the material by one or more drawing nozzles or by one or more pairs of rollers with the addition of one Lubricant is reduced.

Before drawing, the metal is subjected to at least one heat treatment, e.g. B. the glow or the Bright annealing, subjected and oxidized on its surface.

To remove the oxide layer, the metal is usually subjected to a pickling treatment before drawing subject. The material is immersed in a pickling bath containing sulfuric acid or sulfuric acid with a bichromate additive.

The staining creates the desired bare appearance. The metal won't end up every time one or before the start of the next drawing process subjected to the pickling treatment, the oxide layer penetrates penetrates deeper and deeper into the metal surface and worsens the appearance of the material essential.

The aim of the invention is to provide a method for blank drawing of non-ferrous metals in which the pickling process is avoided and still a shiny appearance of the end product is achieved.

In essence, this goal is achieved in that the lubricant is a weak acid and a wetting agent can be added. According to the invention, at the latest before the occurrence of the Workpiece in the last deformation tool on the oxidized workpiece surface an acidic Component and a wetting agent-containing lubricant applied and the oxide layer thereby detached from the underlying pure metal. The wetting agent enables the acidic Component penetration between the oxide layer and the metal surface and thus the rapid Separation of both parts, to which the mechanical removal of the oxide film and the applied Lubricant adjoins from the metal surface except for a remaining lubricant residue. Of the The material entering the drawing tool is then metallically pure, with a thin film of lubricant covered surface. It should be noted here, however, that the addition of wetting agents in the Surface treatment of metals, e.g. B. in phosphating and oxalizing, a common measure represents. ;

Furthermore, it should be noted that the addition of an acidic component to the lubricant and the application of this acidified lubricant to the workpiece shortly before the process for bright drawing of non-ferrous metal semi-finished products, eg. B. Band,
and lubricants for implementation
of the procedure

Applicant:

William Blackwell, Birmingham,
Warwick (UK)

Representative: Dipl.-Ing. KA Brose, patent attorney,
Pullach near Munich, Wiener Str. 1/2

Claimed priority:
Great Britain 16 April 1953

William Blackwell, Birmingham, Warwick

(Great Britain),
has been named as the inventor

its entry into the drawing tools during cold drawing of metals is also already known.

But here it is a matter of drawing bare material with the help of a powder «! Lubricant and the artificial, d. H. deliberate creation of a slightly corroded surface, as experience has shown the lubricant holds particularly well.

The measure according to the invention must after each annealing process, i. H. before the next drawing process and the dissolved oxide layer is removed before the material passes the next drawing tool happened. This is achieved, for example, by giving way to the material between a pair Pillows, e.g. B. made of felt, is passed through, with its surface abraded and the already loosened Layer is removed except for remaining lubricant residues.

The invention further comprises the lubricant for carrying out the method according to the invention. This consists of a mixture of mineral oil, a weak acid and a wetting agent that makes the oil and allows the acid to penetrate faster between the oxide layer and the metal. Amount and concentration the acid are so dimensioned that the oxide layer of the metal is dissolved, the surface of the Metal and the drawing tools are not attacked.

509 837/116

So the lubricant is not only used to protect the surface of the metal and those in contact with it to lubricate coming drawing tools, but also to loosening the by the previous one To cause annealing or oxide layer produced by other heat treatments.

The weak acid is preferably phosphoric acid. Also sulfonic acid, such as. B. benzyl sulfonic Acid, gives satisfactory results.

The wetting agent is preferably an aliphatic alcohol that is liquid at room temperature. Alcohols, that can be used for this purpose are both types of propyl or butyl alcohol also ethyl and methyl alcohol.

A particularly suitable composition of the lubricant can be achieved by a mixture of 182 1 Mineral oil with 1.57 l of commercially pure phosphoric acid and 0.19 l of ordinary butyl alcohol will.

The mineral oil is preferably pure hydrocarbon oil based on paraffin, x \ cetylene or naphthalene. Another oil, e.g. B. a relatively small! Share of. Vegetable oil, fish oil or lubricant containing animal oil.

In order to achieve success, for example, in the cold rolling of non-ferrous metals, especially brass strip must have the metal after the first stage of the drawing process and subsequent heat treatment be wound up in the usual way. The coil then has to peel off the oxide layer be placed in a container with the lubricant according to the invention.

The metal strip is then continuously fed out of the container, so that a film of lubricant remains on its surface and is then passed through a pair of cushions, for example made of felt, that touches the tape on its entire surface and that is caused by the action of the Removed lubricant-loosened layer.

However, the pillows do not remove the lubricant by itself Lubricant full, so that the cleaned belt still has a thin film of lubricant on its surface having. Then the tape runs in the usual way through the Ziehwerlczeuge, z. B. by one or more pairs of rollers, and is there in the presence of what remains on its surface Lubricant quenched.

If a further drawing process or a preceding further heat treatment process is necessary, the measure explained above can be repeated.

The invention can also be used particularly advantageously when drawing metal pipes, where both the inner and outer surfaces of the pipe must be cleaned and lubricated at the same time in order to prevent the pipe from sliding over the stopper to facilitate.

Mixing the oil with phosphorus or other weak acids and alcohol or other wetting agents and surfactants can be obtained by means of conventional mixing devices, e.g. closed containers provided with one or more pairs of motorized blades, be performed.

The invention makes it possible to use the pickling processes that have been customary up to now, in particular the between to dispense with the pickling processes previously activated in the individual drawing stages. This becomes a very substantial savings achieved when pulling. The invention is therefore of considerable importance for the economic drawing of non-ferrous metals.

In addition, there is the further advantage that the oil is more effective with a lubricant according to the invention is distributed over the surface of the material than when working with pure mineral or Hydrocarbon oils is the case. Since the lubricant is now also better than before spreads the surfaces of the drawing tools, it lubricates them on the one hand more effectively, on the other hand it increases the service life of the drawing tools.

Claims (8)

Claims 1. Process for bright drawing of non-ferrous metal semi-finished products, e.g. B. tape in which the Material with heat treatment in front of the individual trains and in presence a lubricant that makes pulling easier on the bare material surface several times Deformation tools, e.g. B. drawing nozzles, is drawn through cold, the oxide layer in front the drawing process to achieve a bare material surface by treating with a Acid is removed, characterized in that at the latest before the workpiece enters the last deformation tool the oxide layer by applying an acidic component and a lubricant containing a wetting agent on the oxidized workpiece surface of the underlying pure metal is detached and that then the oxide film and the applied Medium mechanical apart from a remaining lubricant residue from the metal surface removed. 2. The method according to claim 1, characterized in that the detached oxide layer from the Metal surface is stripped. 3. Device for performing the method according to claim 2, characterized by a pair of cushions arranged on both sides of the material to be drawn, covered with a soft covering, z. B. with felt and can be pressed against the material surface. 4. Lubricant for performing the method according to claim 1, characterized by a mixture of a mineral oil, a wetting agent and a weak acid. 5. Lubricant according to claim 4, characterized by a proportion of phosphoric acid. 6. Lubricant according to claim 4, characterized by a proportion of a wetting agent which aliphatic alcohol which is liquid at room temperature, e.g. B. propyl or butyl alcohol contains. 7. Lubricant according to claim 4, characterized in that the mineral oil component consists of one pure hydrocarbon oil based on paraffin, acetylene or naphthalene. 8. Lubricant according to claims 4 to 6, characterized by a mixing ratio of 182 1 mineral oil, 1.57 1 commercial, pure phosphoric acid and 0.191 common butyl alcohol. Considered publications:
German Patent Nos. 811 900, 747 422;
British Patent No. 604 353. Cited earlier rights:
German patent 904 680. © 609 837 / 11S 2.57