SU1671387A1 - Blank hot moulding procedure - Google Patents

Abstract

This invention relates to powder metallurgy and can be used in the manufacture of end cutting tool blanks. The purpose of the invention is to expand the technological capabilities of the method by providing processing of low-plastic materials and improving the quality of products. Pressing is carried out in the presence in the matrix of the press residue from the previous workpiece, wherein during the return stroke of the punch workpiece is displaced relative to the matrix by the value L = L - H- H ₁ - at a value of the pause between cycles compression Τ≤ [K (T _a -T _to ) / (T _o -T _w )] ² , where L is the amount of displacement of the press product, mm

L - length of the container, mm

H - length of the workpiece, mm

H ₁ - the height of the cylindrical part of the pressure chamber, mm

T _о and T _к are, respectively, the average temperature of the workpiece at the time of extrusion and the temperature of the lower limit of the plastic processing temperature interval, ° C

T _W - temperature stamp, ° C

K = V / 0,336S - coefficient taking into account the ratio of the volume V of the press residue to the average surface S of its contact with the stamp. 2 Il.

Description

The invention relates to powder metallurgy, in particular to the processing of metal powders by the method of hot pressing, and can be used in the manufacture of blanks for end cutting tools

The aim of the invention is the expansion of technological capabilities by ensuring the processing of low-plastic materials.

Figures 1 and 2, respectively, show the pressing patterns at the end of the punch stroke and the moment of loading the subsequent billet.

The schemes include container 1 billet 2, punch 3 die 4 press article 5 pusher 6 collet sleeve 7

The method is carried out as follows.

The billet 2 and punches 3 are pushed into the cavity of the container 1 and heated to hot plastic deformation temperatures through the matrix point 4, and the conical part of the press is pressed, the rest of the pressed shdr and 5 (c | u1). The product 5 is displaced relative to the patric 4 of the odopiocontainer I in direction 1 opposite to the direction of pressing, for example, using a pusher and a collet of the sleeve 7, which encloses the press 5, when moving the pusher a year by pushing the pneumatic cylinder stem ( )

about

oo with

X

 oGp zop about the result of displacement between the inner of the motruch and the press with the remainder (le p), vb and the gap, which prevents the incoordination of the co-inductive heat, nS) f, ef in g. HHVH. As a result, the pressure of the balance of the rest and heat of the matrix are reduced. as the predominant favor of heat transfer between them, the GRPEMI 5 is a heat-pressure press that is shifted by conduction rn and; quantifying the difference in length l gteinr t; i. workpieces and pre-osgat j Orpin I f / P displacement caused by the need to enter the punch at 0intii p in the presence of a punch in it and riper o) the bottom

g, f ress products 5 ohms

t) 1 g of it ra-t is in it spev I / nri / (fig 2) and poangon 3 i to stm) 1 1 rt „with y2 they extend g (and u 1 b is the rest of the preceding jiu it nor i is a nuisance och and matrix 1 do, n h ii sip1 residue on the newly formed product IJHIC s pec product Then the cycle is

T-H 01 (JtTll OTHER DI1LLMI

i ji press i h determine

1 11 (

one ,

G V

n) the faculty of w u ityo 1U

() B (

i g and i V v average

мп г с г l OH OH OH OH) r S S пр пр пр с с с с

 Cs (ii the value of the messenger area prr iid 1 and mon is the matrix about them i iipi i them 1.) Is due to the heat condition ii i-el h 1С1ЛМИ naugoles drying i ii io POJ iir N-exaHki i perekipi Hep: u put n then through water through ii KIM no xi. Therefore, in MCI pi r Lr, the CPRSss product NIa1REo hn j 11 i to iu / ni id) is the most intense (j P1L01SCH with common base 1 and IIL p ij YUn. In connection with this, for the purpose of the sip (ei heat intensity in those

JiO M pti i OST 1TKZ USD KSP LYG FROM

r i t i t i ii4V t HI ti and is displaced by p axial nl i ie. ui i and, in a pure manner, we are / i i it i d i about the troughs that determine - and the condition of g psh; t are npe olladenii (.-onaiKan about JMIJ ii and NOiiTt nnepe after and after roioaKi, u MJT, I from the first condition press iitrjicn to u ig) Dig the maximum IPH ui idifnuu Pr i with it; , Isrii, 1, in the axis of the baiting of the chip-pd it (fr xdlatkog formed the

the cavity is bounded by the surfaces of the conical funnel of the matrix of the press of the rest of the exposed

surface of the press

In the container above the matrix point Due to the tight contact of the cylindrical press, the residue with the container and the core part of the press article with the calibrating section of the matrix with a limited

the entry of air into the cavity creates a vacuum which is proportional to the displacement of the press product

As a result, conditions arise when, due to the insignificant mass of the heat exchanger (air) in the cavity, the convective heat transfer becomes less with an increase in the volume of the cavity, that is, with increasing bias, the intensity of the cooling press of the residue decreases.

0 At the same time, the movement of the press product in the axial direction should be limited so that when installing the subsequent billet on the press residue of the displaced press of the product, the billet is recessed

5 geineers to a depth of at least 5 mm, which is not necessary for the price of a cutoff punch at the entrance to the container

Thus, the displacement of the press unit relative to the die in the axial direction

0, in the reverse course of the punch is determined from the expression

I L N - hi

de I magnitude of the displacement of the press product L container length mm

5hi - height of cylindrical ska

By displacing the press residue relative to the matrix, a significant reduction in the area and surface of its contact with the forming tool is achieved. Calculations show that when pressing with deformation degrees LO- 80% and the conditional height of the press assembly is equal to O 2D where D is the diameter of the container the displacement of the latter relative to the matrix during the reverse course of the punch reduces the contact surface by 50-70%

By reducing the area of the cond idt THbix surfaces, respectively

0, the heat transfer from the workpiece to the workpiece is reduced by heat conduction. This allows or increases the time interval between pressing the previous and next workpieces or at the same time.

B menyu pause that a known method to reduce the pressing force and consequently the wear and dies of the matrix

Example On a crank press K 2I32, hot extrusion of the covaneer) capsule blanks is carried out and

Powder of high-speed steel 10Р6М5 per bar O mm for the purpose of subsequent manufacturing of billet mills from it. Container diameter D 32 mm. length L 70 mm; diameter of the matrix point d 10 mm; diameter of the workpiece Oz - 30.5 mm; height of the rim H 40 mm. The degree of deformation during extrusion is 90%. The extrusion is carried out before the formation of a npecc core in the matrix, the height of the cylindrical part of which is hi - 5 mm and the height of the conical part hz 11 mm

Heating of the blanks is carried out in an inductor so as. hours to 1150 ° C. Omperature of the press residue immediately after the extrusion of T0 1100 ° C. The lower limit of hot treatment with rapnnm is 1000 ° C, and the temperature of the stamp Tx is 300 ° C.

The heated billet is placed in a pre-lubricated container and pushed through a die through the die until a press residue of the specified dimensions is formed. During the course of the punch up, the pneumatic cylinder is turned on and with the help of the pusher the press product is displaced by the value I L - -H -hi -5 20mm.

The time between press cycles is calculated from the expression

g - (V To Tk h2 l

1 To-TuN l ozzzb5 ts; -shu

-36s

for the case of a press residue displaced relative to the matrix, and t - A c - for the case of complete contact of the press residue with a stamp, i.e., according to the proposed method, the time between pressing operations can be extended nine times. Time / ad cycles are equal to 30 c, after which they grease the container, place the next one on the press residue of the previous billet, and squeeze the previous bar in front of it. When extruding all blanks, the sequence and time intervals are preserved.

The density of the obtained rods is estimated by known methods in the longitudinal and transverse sections.

i.- m rrchi firo Mt. ü n u.-iec-Mi о: н jjo; iria uo of all units -si etchh and 99.9%. The comparison is tight, and 1 nnyi:;,. . The scientists, according to the proposed method, and which, including the one with the help of graphite by mass, showed that in the latter cases the front end of the preparation with a length of up to 5 10% of the total bar length has a porosity of up to 15% this, when producing rods using a known method chchsp bar with a low quality of material nsobkho / v -io removed

F o o m l a

The method of hot pressing of the log, including i-uipen, loading into the moldings of the lane and pressing the workpiece through a matrix with a conical lead-in part with the formation of the priss residue of the previous workpiece, which is heated, possibly for expanding the technological walls by securely processing low-plasticity materials. prior to pressing, aseptic displacement of the nano press residue with the press is carried out relative to the die in napralepia the opposite direction of pressing by the amount

i L - N - h 1 5 mm, where L is the length of the container, mm;

H is the length of the workpiece, mm;

hi is the height of the cylindrical part of the press residue, mm

when the pause between the cycles of pressing

(K J, 2 I about I 1b

where G0 is the average temperature of the workpiece in the momong end) and pressing C,

Tg - temperapat / ra of the lower boundary of the hem-inceptic pnervapa of plastic processing, ° С;

TUi - temperature stamp ° C

T trtor with r: oefb11ts | Snt taking into account the ratio of the volume V of the press residue to the average surface S of its contact with the stamp.

ig

h bw

Claims (1)

Claim A method of hot pressing blanks, including heating, loading into a container and pressing the blank through a die with a conical lead-in to form a press residue st of the previous blank. I distinguish u with that. that, with the aim of expanding technological capabilities by ensuring the processing of low-cost materials. and l about in. before pressing, the press residue is axially displaced with the press product relative to the matrix in the direction opposite to the pressing direction, by the value i - = L - H - h 1 - 5. mm, where L is the container length, mm; N - the length of the workpiece, mm: hi is the height of the cylindrical part of the press residue, mm; with the amount of pause between pressing cycles ,. (and J p 'Tk) ² I о I iij where To is the average temperature of the workpiece at the time of pressing, ° C; Tk is the temperature and temperature of the lower boundary of the temperature range of plastic processing. ° C; Tui - stamp temperature, ^s C: ___V 0,336 S ’ K - = coefficient taking into account the ratio of the volume V of the press residue to the middle surface S of its contact with the stamp.