DE1002273B - Process for building up the fluid pressure in a hydraulic ironing device for wire and device for carrying out the process - Google Patents

Description

The invention relates to a method and a device for building up the fluid pressure in a hydraulic ironing device for wire in which the wire is reduced in cross-section under perfect fluid friction.

One speaks of. perfect fluid friction when the lubrication conditions are such that the opposing surfaces in all operating conditions occurring through a lubricant layer SO 'are separated from each other that no direct contact takes place between the surfaces. Compliance with these conditions implies, among other things the use of a liquid lubricant. In some cases, you can also use a lubricant use, which is initially in the solid phase, but under the pressure conditions that prevail in the boundary layer in question for the lubrication, changes into the liquid form.

It is known that when a wire is pulled through a pipe which is narrowed at the outlet end and the inlet end of which is immersed in a lubricating liquid, a certain liquid pressure is formed. A wire drawing device is also known in which a tube leads to a closed chamber from which the wire passes to a drawing iron. The wire is used as the moving part of a pump and a lubricant is supplied to the wire as it enters the tube. As the lubricant is drawn into the tube, a fluid pressure of the order of 1.75 kg / cm ² and above is created in the chamber; however, the cross-sectional reduction of the wire is exclusively caused by the drawing iron.

In contrast to this, according to the invention, the reduction in area is caused by liquid pressure of the lubricant caused by a pressure created by that known pumping action of the wire is built up in a cavity through which the wire passes.

The method of the invention requires very careful tuning between the wire on the one hand and the pipe or the outlet on the other hand existing clearance to the wire speed, the drawing tension and the mean viscosity of the lubricant in order to achieve one in the lubricant To build up liquid pressure which is sufficient for plastic flow and thereby a reduction in cross section in the wire to evoke.

The invention is based on the following knowledge: If a wire of known diameter with a known speed through a pipe of known clear width and known length, which has a narrowed outlet, the inner diameter of which is no larger than the initial outer

procedure

to build up the fluid pressure
in a hydraulic ironing device

for wire and furnishings
to carry out the procedure

Applicant:

National Research Development
Corporation, London

Representative: Dr.-Ing. F. Wuesthoff, patent attorney,
Munich 9, Schweigerstr. 2

Claimed priority:
Great Britain October 1, 1952

Derman Guy Christopherson,

Headingley, Leeds I, Yorkshire (UK),

has been named as the inventor

diameter of the wire, -and becomes a lubricant known viscosity under the pressure and temperature conditions prevailing in the environment fed to the pipe end at which the wire enters, then the lubricant can be inside of the pipe developing pressure can be calculated according to the formula given below, where the following applies:

H = radial play, ie the difference between the starting radius of the wire and the inner radius of the pipe in cm
L = pipe length in cm
V = speed of wire passage through

the pipe in cm / sec
Z = mean viscosity of the lubricant in the

ti u -n (^ VH ' ^sec )

Tube in, poises ₅ - -

cm ²

P = pressure of the lubricant inside the pipe in dynes / cm ²

3.40 -ZVL

^{p =} w

In the method according to the invention, the cross-sectional reduction of the wire in one Step or in the same facility in two steps.

609 770/134

If the one-step procedure is used, then the dimensions of the device and the wire and the speed of passage of the wire through the pipe is determined so that the fluid pressure built up in the pipe together with that on the Wire drawing tension, d. H. in return, the entire cross-sectional reduction of the wire before the wire passes through the constricted outlet. In these circumstances there is

To cause the wire to vary in the cut, a considerably larger one runs through the puller Amount of lubricant. This has the consequence that

1. Within the narrowed outlet the wear decreases considerably, especially the ring-shaped one Wear which, as those knowledgeable in the field of wire drawing, occurs in conventional drawing dies in tends to occur near that point

2. the one used to pull the wire through a given Drawing iron required drawing force is significantly reduced and

3. the wire produced is more uniform.

These advantages are only fully achieved if the lubricant is in the area immediately prevailing liquid pressure in front of the outlet constriction and that on the. Wire through that

Fig. 1 is a section of a wire drawing tube with a restricted outlet which is integral with the Pipe consists;

Fig. 2 is a cross-sectional view of a modified wire puller in which one containing the constricted outlet Piece is screwed pressure-tight to the pipe; Fig. 3 is a section through a modified embodiment the device according to FIG. 2.

When you perfect a wire through a pipe Fluid friction · leads both in the pipe io, whose diameter is a little larger than that like in the narrowed outlet. '' is the initial wire diameter and the one

If, on the other hand, the two-stage process has a narrowed outlet, then a deformed one is formed, the dimensions and the working of the wire, sufficient pressure just before conditions, are chosen so that the narrowing in the pipe is formed in the annular forming fluid pressure and that of the wire 15 area indicated by A in Figs. If the tension is formed, an initial diminishing pressure is large enough to cause the cross-section of the wire to cross the area. ^ And that a
final cross-section reduction is effected,
while a frictional contact between the narrowed
Outlet of the tube and the outer surface of the wire 20
consists. Under these circumstances, the narrowed one works
Outlet like a. common drawing iron, and while in
the pipe has perfect fluid friction,
there is the same lubrication for the drawing iron surfaces

how it is in the drawing die with the usual drawing avoidance of the drawing die diameter equal to that of the wire trains. knife is before drawing,

It is already known a pulling device in which
a lubricant is placed in a pressure-tight chamber
high pressure is introduced, up to 2000 kg / cm ²
can be. The pressure is through a special 30
Pump delivered in contrast to the present one
Invention in which the pressure is generated by the movement of the
passing a narrow passage. Wire is built up. By using the well-known pumping action of the
Wire used and according to the invention the game between fluid friction and the retraction - if a see tube and wire is used, taking into account that - the tensile force exerted on the respective material and the drawing speed of the wire above its flow limit, which is carefully coordinated, it succeeds safely - is defined as the stress which that which forms liquid pressure is erzustellen conducive deformed to a permanent elongation of the wire to the wire, even if substantially no by 0.1% to cause the pressure of its length, is less than 2000 kg / cm ² . By matching the wire with one of the shown in FIGS. 1, 2

the dimensions of the puller to the one shown and 3 optionally illustrated devices Drawing speed and the material slowly at first and then with increasing speed If the wire to be drawn succeeds in drawing a deformity, it is shown that, during the pressure tion of the wire through its own pumping action 45 in the outlet immediately in front of the constricted outlet Achieve without external pressure on the lowing area on the in the previous paragraph Lubricant applied too. what is needed is what naturally increases, the pulling force on you borrowed represents a considerable simplification. Minimum value drops when the conditions are fully

The following should also be emphasized. Have stopped when fluid friction occurs. the The method according to the present invention supports 50 drawing speed should be equal to or greater than for the total cross-section reduction one is looking for the speed that is required to run under the or for a substantial part of the same on the given conditions this minimum pulling force to ef-fluid pressure and is therefore needed for the areas.

intentional deformation not due to radial pressure Another advantage of the invention is presented in the following

to leave between the drawing iron and the material. This is described as follows: In the space between As a result, the wire and pipe flow close to the surface of the wire

Lubricant inward in the direction of the wire movement while it is following near the pipe wall flows outside in the opposite direction. So you have a cycle that tends to be about to convey material particles removed from the wire surface during the drawing back to the inlet.

The following table shows examples of

the wire surface can occur as a result of the measurement values obtained when drawing copper and the cross-sectional steel of low carbon content going on in the drawing iron at the specified reduction. ^: Speeds and when using mineral

In the following, the invention will be considered to be more moderate on the basis of oil lubricants of the specified viscosity Drawings. led to several satisfactory results. It can too playing a wire drawing device explained. 70 other dimensions can be used. If for example

and accordingly a smooth wire surface
can be achieved much more easily than in the case
the previously known method in which the workpiece
is drawn inside the drawing iron.

This in turn has the advantage that the present method does not need to come into undesired contact between metal and metal,
that in the known methods due to the roughness

wisely, the clearance between the wire and the tube is chosen to be smaller, or if a lubricant of greater viscosity is used, the tube can be kept shorter. The values given in the table ^have: experimentally proved favorable. However, they are only to be regarded as examples.

Pull
speed
na / sec Soft copper wire Inside diameter
of the pipe
mm length
of the pipe
cm Wire diameter
mm 4.0
10.0
4.0
10.0
4.0
10.0 lubricant
viscosity in poises
at 25 ° C
and atmospheric pressure 0.85
0.85
0.6
0.6
0.35
0.35 4.75
7.00
3.25
4.00
2.00
2.50 0.8
0.8
0.56
0.56
0.32
0.32 4.0
1.0
4.0
1.0
4.0
1.0

Steel wire low carbon content Inside diameter
of the pipe length
of the pipe Wire diameter Pull
speed lubricant
viscosity in poises
at 25 ° C cm mm m / sec and atmospheric pressure 5.25
7.75 0.8
0.8 4.0
10.0 3.75
4.50 0.56
0.56 4.0
10.0 2.25
2.75 0.32
0.32 4.0
10.0 mm 4.0
1.0 0.85
0.85 4.0
1.0 0.6
0.6 4.0
1.0 0.35
0.35

^{The liquid pressures 1} in question when using the method according to the invention can be calculated using the formula given in the first part of the present description. As a general guide, drawing soft copper requires a liquid pressure on the order of 700 kg / cm ² to achieve deformation and perfect liquid friction, while for low carbon steel the required liquid pressure is on the order of 1400 kg / cm ² .

The invention also comprises a device for wire drawing which is known in its basic structure, as illustrated for example in the drawings.

According to Fig. 1, the device comprises an inlet pipe 1 of predetermined length and predetermined internal diameter with a narrowed outlet 2. The inner diameter of the tube narrows to the Outlet towards, and the outlet 3 widens outwards. There is a mounting flange 4 on the pipe shown, but any other attachment can be used. The establishment according to FIG. 2 comprises a narrowed inlet 5, which is shaped like a conventional drawing die and in a bearing 6 is arranged, which has an outwardly widening opening 7, the outlet is through an intermediate piece 8 attached to the end of the tube 9. The outlet 5 is in this way firmly against a sealing washer 10 pressed so that there is a liquid-tight connection between it and the tube. the The device according to FIG. 3 differs in that the bearing 11 is attached to the pipe end and that the constricted outlet 5 accommodated therein with the interposition of a sealing piece 12 against; the The end of the pipe. The parts are fastened by a nut 13 screwed into the bearing. In all Cases must be the inside diameter of the pipe according to the above formula with reference to the initial diameter of the wire to be drawn, the pipe length, the viscosity of the lubricant to be used and the Wire drawing speed can be calculated as explained earlier. Also, these dimensions depend and calculations also depend on whether a lubricant pressure is required within the pipe to produce sufficient to cover the entire cross-sectional reduction of the wire in one step to be carried out, or whether to work in two steps. The lubricant is the open one The end of the tube is fed, the wire taking up the lubricant as it enters the tube.

As a result of the fluid friction a certain

Temperature rise is inevitable, it may be necessary to water the facility or on other way to cool. It can also be used to simplify fabrication in terms of the for that Pipe required dimensions - inside diameter and length - it may be necessary to assemble the pipe from parts. The sections can then be joined together by connections that are able to withstand the internal pressure in question are.

It is clear that the viscosity of the lubricant is of paramount importance. Mineral oils have the advantage that their viscosity increases with pressure, so that the pressure can be built up more easily can; however, it is more common in wire drawing to use a water-based lubricant.

If necessary, a few preliminary tests ^{1 determine} the most suitable type of such liquids. If a mineral oil lubricant is used, it may be found that the wire should be cleaned prior to any further treatment. It is possible that according to the present

Drawn Invention: Wire is not bare. Should he Wire must be bare, so it can be polished before or after drawing,

Claims (5)

PATENT CLAIMS: 1. Method for building up the fluid pressure in a hydraulic ironing device for wire, where this passes through a cavity of the device, which has a narrowed outlet is provided, is pulled through and thereby before reaching the outlet by the action of Liquid pressure experiences a reduction in its cross section, characterized in that the liquid pressure due to the known pumping action of the passing through. Wire in that Cavity is built up. 2. The method according to claim 1, wherein the using a high lubricant pressure with wire coated with a lubricant skin is ironed in a drawing nozzle, characterized in that that the wire in. The narrowed outlet a further reduction in cross section by drawing learns. 3. The use of a tubular casing through which the wire runs, which is on the input side open, and on the other side is provided with a narrowed outlet and its Length and bore with the wire diameter, wire speed and lubricant viscosity are matched so that due to the generated by the wire passing through. Pumping action a lubricant pressure is built up as a device for carrying out the method according to claims 1 and 2. 4. Device according to claim 3, characterized in that the outlet (2) is known per se Way is designed as a drawing nozzle (5). 5. Device according to claim 4, characterized in that the drawing nozzle (5) is exchangeable is. Considered publications:
German Patent Nos. 584 282, 440 435;
British Patent No. 566,434. 1 sheet of drawings © 509 770/134 2.57