DE1916798A1 - Drawing ptfe coated wires in the cold - Google Patents

Abstract

Process for cold drawing wires of steel, ferrous alloys or non-ferrous alloys is characterised by the wires being provided with an organic coating of the PTFE type before being drawn. The low frictional coefficient of the PTFE coating enables the coated wires to be cold drawn, with the use of gently reduced amounts of lubricant. Draw speeds can be increased, and metals difficult to draw, such as titanium and its alloys, can be more easily drawn. Tungsten carbide drawing elements can be used in place of diamond draw elements, and these elements have a longer life.

Description

Process for wire drawing and drawing of steels and ferrous ones alloys and non-ferrous alloys The present invention relates to a method of twist drawing and drawing of steels and iron alloys and non-ferrous alloys Wire drawing and drawing of corrosion-resistant steels, Refractory steels, ferrous and non-ferrous alloys is generally used as a starting point carried out by a lubricating carrier layer.

These carrier layers can, depending on the degree of deformation to be achieved: metallic substances (lead, copper, etc.) or chemical compounds (oxalates, phosphates, or the like).

These backing layers have the following disadvantages: a) in their application: poor adhesion, irregular application, toxicity, Changes during storage, difficulties with removal, and the like.

b) in their effectiveness: more or less limited deformations, limited deformation speeds, grainy surfaces, irregularities and the same.

Certain alloys can age at relatively low Temperatures are not used as carriers for high-temperature metallic coatings to serve.

Others (especially titanium and itan alloys) eat their way with the Carriers of classic lubricants.

These alloys can only work with difficulty and always under high cost to be deformed to the extent necessary for their processing.

The object of the invention is therefore to eliminate these disadvantages, Increasing the speed of wire drawing and pulling and reducing the Manufacturing price.

To this end, the invention provides a method of drawing wire and drawing of steels and ferrous or non-ferrous compounds, which is characterized is that the drawing material made of steel or other alloys beforehand with an organic Coating made of a polytetrafluoroethylene (PTFE) or a derivative is provided.

The main advantages of this procedure are as follows: Ease of use its i) implementation, its constancy, the low price of the in numerous Cases of usable lubricants such as soap, mineral oil and the like Deformation speeds, the possibility of a significantly larger reduction in cross-section, the long service life of the drawing tools, the possibility of using drawing dies made of carbide instead of drawing iron from the much more expensive diamond, the results because of the extraordinarily lower coefficient of friction, the perfect one Stability of the process, which is in contrast to certain known substances, such as 3. Copper and lead.

The removal of this coating on thermal, chemical (acid, Lye), electrochemically or with the help of an organic solvent drawing leads to a noticeable simplification of the manufacturing difficulties and consequently a reduction in the duration of the manufacturing process.

The surface quality of the created with the help of this coating Drawn products is significantly better, while the adhesion of such a plastic coating, in contrast to one of the classic carrier layers described above, none requires prior fastening or pickling processes, which are always dated Are disadvantageous from the point of view of the end product.

certain industries, which include drawn, wire-drawn or wound products process, require a previous surface treatment, thus a final processing becomes possible: this is especially the case in the manufacture of springs.

The organic coatings made of PTFE or its derivatives allow im generally solving the problems posed the direct Application of a coating, its deformability and regularity a special one ensure slight deformation.

For a better understanding of the invention, the following is considered as not limiting embodiment written a complete drawing process that is carried out according to the process forming the subject of the invention.

In this example it is a question of using a steel profile of the following composition: C = 0.10, Itn = 1.02 1 Si = 0.73%, Ni = 8.1%, Cr = 17.3%, to be drawn from a thickness of 5.5 mm to a thickness of 3.2 mm.

This wire is previously made with a thickness of several thousandths of a millimeter (some> 1) thick layer of polytetrafluoroethylene coated which simply during applied by passing through a bath and then also during the Is polymerized at about 100 0 C run through. The wire drawing speed is 12 m / min.

One then begins pulling under the following conditions is carried out: The degree of cold deformation between two stitches is approximately 32% instead of a maximum of 18 according to the klasst method.

The pulling speed is 170 m / min. at least instead of 80 m / Nin. at most with known processes.

The tungsten carbide drawing tool costs much less than a drawing tool made of diamond. In the method according to the invention, its service life is at least three times as long as the service life of a drawing tool of the same basic type, which is not used according to the invention.

The removal of the coating takes place either in a basic environment ( 20 - 80 parts by weight) in the heat (at 50 - 80 degrees C), or in sour Environment (hydrofluoric acid: 10 to 30% nitric acid, 2 to 10% hydrofluoric acid) in the heat (at 50 - 80 degrees C).

The wire then has a perfect surface finish on.

- Patent claims: -

Claims (3)

Claims: 1. Process for drawing, wire drawing or cold drawing of steels or iron or non-iron compounds shows that the drawing of steel or other alloys beforehand an organic coating made of polytetrafluoroethylene or its derivatives will. 2. Drawing method according to claim 1, g e k e n n z e i c h n e t d u r c h any of the following characteristics or any combination thereof: a) the drawing process takes place thanks to the low coefficient of friction of the organic Coating dry instead; b) an additional lubricant can be provided; c) drawing is carried out with tungsten carbide drawing tools; d) the distance the plastic coating takes place thermally; e) the removal of the plastic coating takes place chemically either in an acidic or in a basic environment; f) the The plastic coating is removed electrochemically; g) the distance the plastic coating is carried out by dissolving it in an organic solvent. 3. Products obtained by the method g; elß claim 1 or 2, the k e n n s e i c h n e t are due to a very improved surface quality, due to the fact that the surface of the drawn stock does not require any special treatment process was subjected to, as is the case with Klasslschen Process the ball is to increase the adhesive force of the coating in an artificial way.