SU1581400A1 - Method of drawing wire in the mode of hydrodynamic friction - Google Patents

Abstract

The invention relates to the processing of metals by pressure and can be used in drawing production in the manufacture of fine and very fine wire. The purpose of the invention is to increase productivity by reducing wire breakage. The method of wire dragging in the hydrodynamic friction mode involves pulling the workpiece through the pressure nozzle and deforming fiber using a lubricant, which is injected into the pressure nozzle and additionally supplied from the source pressure to the deformation source, the amount being calculated according to the formula Q = ϕV 0R 0 / 4A [(R 2 + 1) LN RH (R 2-1) (1 + 2A), where Q is the volume flow rate of lubricant, m 3 / s

A = * 98MV 0L / Σ SR 2 R * = R H / R 0, Σ S is the resistance to plastic deformation of the material being pulled, PΑ

R H and L - radius and length of pressure nozzle, m

R 0 - radius of the billets to be procured, m

μ - dynamic viscosity of lubricant, pa. s

V 0 is the speed of movement of the workpiece, m / s.

Description

The invention relates to the processing of metals by pressure and can be applied in the drawing industry in the manufacture of fine and very fine wire.

The aim of the invention is to increase productivity by reducing wire breakage.

The essence of the proposed method is as follows,

A lubricant that is under pressure in the cavity formed by the procured workpiece, the pressure nozzle and the die, flows into the gap between the surfaces of the pressure nozzle and the workpiece in the opposite direction

the movement of the workpiece (the direction of drawing). Thus, the lubricant prevents dust and particles of the metal being pulled into the lubricating cavity, remaining on the surface of the workpiece after the previous passage, and also facilitates the removal of delaminations and dust formed at the entrance to the deformation zone. This leads to a decrease in friction forces and an improvement in lubrication conditions in the deformation zone and, consequently, to a reduction in the breakage of the protruded product. Moreover, when lubricant flows in the gap between the pressure nozzle and the workpiece, a contactor of the OS appears on the surface of the procured workpiece.

The stresses from the action of viscous friction, the resultant of which is directed in the direction opposite to the movement of the workpiece. Thus, the lubricant, moving in the direction opposite to the dragging, has a braking effect on the workpiece, which is characterized by contraction and reduction of the specific pressure of the metal being worked die, reducing the contact friction in the deformation zone, the breakage of the product being pulled and thereby increasing the productivity of the dragging process. of the hydrodynamic mode of friction, it is necessary to apply lubricant to the entrance to the deformation zone under pressure, calculated using the formula

Р „2 6, (In gn - 2a) / (rJ -1),

where a pV0L / 6sr0J;

p - dynamic viscosity of lubricant

Pass;

Vfl movement speed of the drawn wire, m / s; g n and L is the radius and length of the pressure nozzle, m;

G0 is the radius of the wire being drawn, m;

6 $ - resistance to plastic deformation of the metal being processed, Pa;

g gn go °

At Р Р Р the increase in forces of external friction will be observed in the deformation zone about

At Р Рn, the workpiece will be thinned to the deformation zone, which will lead to an increase in the degree of deformation per pass, resulting in possible stretching and breaking of the pulled product about

Example, when drawing a copper wire with a diameter of 40 μm, which has a resistance to plastic deformation of 300 MPa, on a lubricant with a viscosity of 0.003 Pa-s (water-oil on the emulsion at 40 ° C) at a speed of 20 m / s through a pressure nozzle having a length of 50 mm and an internal diameter of 0.5 mm, and then through the fiber it is necessary to ensure the outflow of lubricant in the amount of 58.8 itlU M3 / Ci for which the entrance to the hearth

deformation serves lubricant under pressure of 9.63 MPa. Calculations show that in the proposed technical solution, compared with the prototype, the pressure value of the drawn billet for fiber is 31.1 times less.

The proposed method of drawing the thinnest wire in comparison with the prototype makes it possible to increase the productivity of the drawing process by 30%, to increase the wear resistance of the drawing tool, to reduce the specific pressure of the drawn billet on the fiber, to prevent the ingress of particles and dust, and to remove the newly formed delaminations and dust from the lubrication channel, reduce the drift of the product, improve the surface quality of the drained products0

Claims (1)

Formula invented shadows Method of wire drawing in the mode of hydrodynamic friction, including pulling the workpiece with a gap through the pressure nozzle and deforming the wire using grease pumped by the workpiece into the pressure nozzle clearance and additionally supplied from the source of pressure to the deformation zone, characterized in that by reducing the wire breakage, the lubricant is fed to the inlet of the deformation zone in an amount equal to q Vere4M a (g-H) In g n - - (rj-l) (1 + 2a)}, where q is the volumetric flow rate of lubricant, m3 / s; V0 is the speed of movement of the workpiece, m / s; . rft — radius of the workpiece to be procured, m; and pV0L / &s-r;; and - dynamic viscosity of lubricant, Pa - s; 6e resistance to plastic deformation of the material being held; g nr / r0; g "and L is the radius and length of the pressure head on the cages, and