SU1681996A1 - Billet for pressing parts preferably of hard-to-shape and non-malleable precision alloys - Google Patents

Abstract

The invention relates to the field of ferrous metallurgy, in particular to the processing of metals by pressure for pressing blanks of hard-to-deform and low-plastic alloys. The purpose of the invention is to increase the yield by increasing the quality of the surface. The blank for pressing is made with through central and additional openings filled with lubricant. The proposal relates to the calculation. The invention relates to ferrous metallurgy, in particular to the processing of metals by pressure, and can be used in the extrusion of products. The aim of the invention is to increase the yield by increasing the quality of the surface. Figure 1 shows the workpiece, top view; figure 2 - section aa in figure 1; in FIG. 3, the region of existence of an optimum pathway of its volume in the through holes, which makes it possible to provide the necessary and sufficient amount of technological lubricant when it continuously enters the apertures of the multichannel matrix to create a uniform layer on the surface of the extruded rods. The diameter of the central hole is determined from the relation d D / D3ar V (V - 1) - n the diameter of the additional holes is determined from the inequality 0 d / D3ar V (k2 - 1 Vn the diameter of the total circumference of the centers of the additional holes) / D3ar 0.7 k, where k 1.03 .... 1.08 - filling ratio of container blank; D-diameter of the central opening of the workpiece, mm; Oeag - diameter of the pressed workpiece, mm; d - diameter of the additional coaxial hole of the workpiece, mm ; Do - the diameter of the total circumference of the centers of the additional holes of the workpiece, mm; k - coefficient determining the presence of lubricant on the outer surface of the workpiece; n is the number of coaxial additional holes of the workpiece, equal to the number of channels of the matrix. 3 Il. (L S o 00 th ON the dimensions of the workpiece in dimensionless coordinates a - D The workpiece 1 has a central through hole ( axial) 2, filled with technological lubricant, and several additional through coaxial holes 3, also filled with technological lubricant. When placing the workpiece 1 in the press container, the lubricant is disposed throughout the entire volume of the container, including the die.

Description

Between the workpiece and the wall of the container is a layer of smears. The extruded product leaves the die with a layer of lubricant on the surface.

In the final form, the expressions that determine the optimal parameters of the blank for multichannel pressing are presented in dimensionless (reduced) form. The analysis of these expressions for the existence of the region of the claimed parameters is shown in Fig. 3,

In the calculation, the parameters included in the mathematical expressions in deriving the dependencies are accepted, 0Cm is the lubricant consumption through c.-l. cross section; Omet - metal consumption through k.-l. cross section; 0.785 years / 4; DK - diameter of the container; Ozag - the diameter of the workpiece; D and D1 - diameter of the central axial bore of the workpiece; ch is the diameter of the pressed bars along the layer of lubricant; dz - diameter of the rod without a layer of lubricant; d is the diameter of coaxial additional holes of the workpiece; Do is the diameter of the centers of the diameters of d and di; 6 (di - d2) / 2 - thickness of the grease bar; n is the number of coaxial additional holes, equal to the number of channels of the matrix; Vnpecc is the pressing speed; VBHT - bar exit speed from the matrix; V is the flow rate near the matrix surface on the diameter Do; x is the valley of the cross-sectional area of the lubricant layer and rod in the matrix channel; x is the proportion of the cross-sectional area of the coaxial additional hole d; k is the fill factor of the container blank;

a 0/0 zag

P d / Ozag f - reduced diameters

Do / D3arJ respectively D .d and Do.

Consumption of metal and grease when moving through the press container

Omet - 0.785 (Dfaar - D2) VnBecc; Osm 0.785 (O2 - 02zag + D2) Vnpecc; (1) Omet + Osm OJ85D to Vnpecc; Consumption of metal and grease at the exit of the multichannel matrix

Omet - 0.785d5n Uvyt;

OSM 0.785I - d2) n VBMT; (2)

Omet + Osm 0.785 n Vol.

By the condition of continuity of flow, from the equality of the right sides of expressions (1) and (2) receive

Ok vnpecc

nd

From the condition of constant material consumption during pressing, for one channel of a multichannel matrix with sufficient

 YOU ARE T

(3)

accuracy can be approximated

0.785 (02k - D23ar) Vnpecc / P

 0.785jfd3 - d3) x VBWT; (4)

0.785D2 VnPecc / n - 0.785 (di2 - d22Xl - x) VBb.T;

(five)

0.785 (0 - Dzo) V / n - 0.785dz2 x V - 0.785 (02k - D23ar) Vnpecc / n; (6)

0.785 (D2o - D2) V / n - 0.785 d2 (1-x) V -0.785D2 VnPecc / n. (7)

Low error with equal error of lubricant and metal consumption from the central part and periphery of the workpiece in the cross section of the matrix channel, i.e. , 5, and equating the left parts of expressions (4) and. (5), get

D YD2-D2ar (8)

Subtracting expression (7) from expression (6) for the same value of x is obtained

Oo-Ok 0.70k. (9)

If there are additional coaxial holes in the workpiece and suppose x1 0.5, by analogy with the expression (7, the right part), we can write

0.785D2 / n 0.785 (D) 2n + 0.785d2. (10) whence D is defined as

D YD2-nd2 - Taking into account the expression (8)

where

D YDS-Diar-nd2

(eleven)

(12) (13)

() / n.

where n is 2,3,4 ....

Expressions (12) and (13) determine the region of existence (field) of the possible optimal values D and d of the blank for pressing through the multichannel matrix together with expression (9), which is the condition for matching the blank with the matrix, i.e. diameter of centers

d of the workpiece is simultaneously the diameter diameter of the matrix channels di. Additional matching conditions are the absence of a center channel in the multichannel matrix and the equal number of holes d and di.

In practice, the diameter of the container and the workpiece are usually constant. In this case, the Ozag billet diameter value is less than DK by the size of the lubricant layer and depends on its properties and the convenience of inserting the billet into the printer, i.e. they are interconnected through „DK

D3

1.03. . . 1.08.

from where

D, c k-D, ar. (14)

Expressions (12), (13) and (9), taking into account (14), can be rewritten in the form

D -nCd / Daar) 2 ° 38Г: О d: V (K2 -, Ozag unitary enterprise;

Do 0,7k-Ozag or, designating through and. $ -

UserUaar

P

u get accordingly

Uaar

(, (2-i) -n

() / n;

At 0.7k,

where k is 1.03 .... 1.08; n 2, 3, 4 ....

Billet 1 from low-plastic and hard-deforming alloys can be made in three possible variants, namely, only with a central axial bore 2, with a central and additional coaxial bores 2 and 3, only with additional coaxial bores 3.

A common case is the second embodiment of the preform. The first and third options are private.

The optimum amount of lubricant enclosed in the container together with the workpiece in the holes and on its side surface to ensure continuous entry into the matrix channels during pressing of the rods with a layer of 0.3-0.5 mm throughout the pressing process evenly throughout the length of the rod, determined by calculation. In this case, the lubricant enters the matrix funnel to each channel by opposing flows either only in the radial direction or in the radial and tangential directions simultaneously.

Pressing is performed as follows.

The workpiece is installed in the container so that the additional holes are located strictly symmetrically with respect to each matrix channel along the common circumference of their centers. At the same time, a lubricating technological washer is installed between the workpiece and the die, the shape and size of which corresponds to the profile of the die and the lead-in part of the workpiece and

ten

15

20

25 30

35 0 45 50

pressing to reduce peak pressure at the initial stage of compaction.

The heated metal begins to flow into the channels of the matrix. The pressurized lubricant due to the frictional forces between the pressed metal and the surface of the matrix funnel is distributed in an even layer, including surface areas adjacent to the separation planes of the moving metal flows, which ensures uniform lubrication along the perimeter of the rod in the matrix channel.

Fig. 3 in dimensionless coordinates a -fi shows the region of existence of optimal parameters of blanks for pressing through multi-channel matrices in the form of a family of parabolic type curves for n 2; 3; 4 and IR 1.03; 1.05; 1.08. Each of the curves for given values of p and k represents the geometric locus of the points whose coordinate values (a, 3) determine the necessary and sufficient amount of process lubricant to be inserted into the workpiece to obtain pressed rods coated with a uniform layer of lubricant of the required thickness. The points on the curves correspond to the second variant (general) of making the blanks. The intersection of the axis of ordinates (a) with the curves gives the points corresponding to the first variant, on the intersection of the curves with the abscissa axis (| 3) the points corresponding to the third variant are found.

Claims (1)

Invention Formula A blank for pressing products mainly of hard-to-deform and low-plastic precision alloys, made in the form of a cylinder with central and additional holes filled with grease and evenly spaced around the axis of the central hole, so as to increase the yield by increasing the surface quality The diameter D of the central hole is determined from the ratio (k2-1) Uaar where k 1.03 ... 1.08 is the filling ratio of the container blank, which determines the presence of grease on the outer surface of the blank; n is the number of additional holes of the workpiece; d - diameter of the additional hole, mm:  (Y (k2-1) / p) Oz g; and the diameter Do of the total circumference of the centers. The zag diameter of the compression billet, mm; the additional holes are determined from the diameter d; the additional holes are determined by the inequality of 5 Do 0.7 k-D3ar. F o.2 0.1