GPV-1 hot pressing installation

G P V - 1 H O T P R E S S I N G I N S T A L L A T I O N

D. I . P o l y a k o v a n d V. S . M a k e e v UDC 621.762.4.016.2

The hot p r e s s i n g technique p lays an i n c r e a s i n g l y impor t an t ro l e in powder me ta l l u rgy p r a c t i c e , but the equipment used fo r th i s p r o c e s s in i ndus t ry has r e c e i v e d r e l a t i v e l y l i t t l e a t tent ion in the l i t e r a t u r e [1-6]. A d e s c r i p t i o n i s given below of the des ign of a hot p r e s s i n g ins t a l l a t ion intended for opera t ion in a vacuum or a p ro t ec t ive a t m o s p h e r e .

Technica l Speci f ica t ion

Maximum t e m p e r a t u r e . . . . 2000~ Fu rnace environment :

vacuum . . . . . . . . . . . . . 1 �9 10 -3 m m Hg i n e r t gas p r e s s u r e . . . . . . up to 0.7 a tm gauge

Heating chamber power . . . . 80 kW Effect ive c h a m b e r space :

d i a m e t e r . . . . . . . . . . . . 100 m m height . . . . . . . . . . . . . . 250 mm

Maximum p r e s s i n g load . . . 6 tons P r e s s punch s t roke . . . . . . 250 m m Cooling w a t e r consumptior~ . 3.0 m3/h Total weight . . . . . . . . . . . 2 tons Overa l l d imens ions . . . . . . 1800 x 1200 x 2600 mm

The in s t a l l a t i on cons i s t s of a vacuum e l e c t r i c furnace and a hydrau l ic p r e s s . A d i a g r a m of the in- s t a l l a t ion i s i l l u s t r a t e d in Fig . 1. The v e r t i c a l r e s i s t a n c e furnace i s composed of a heating c h a m b e r and gas evacuat ion and f i l l ing s y s t e m s . The heat ing chamber (Fig. 2) i s mounted on a f r a m e . Within the w a t e r - cooled cy l ind r i ca l she l l of the chambe r a r e housed a g raph i t e pe l l e t l ining, s t a in l e s s s tee l s c r e e n s , and a heat ing e lement , which i s made f rom an EG-0 g raph i t i zed e l ec t rode .and i s in the fo rm of a sp l i t tube [7] of 120-ram ins ide d i a m e t e r and 600- ram length.

F o r charg ing the fu rnace , i t s bot tom l id , which i s p rov ided with a g raphi te box f i l led with graphi te pe l l e t s , i s lowered . Tlhe l id i s l owered and r a i s e d manual ly . On the upper l i d i s mounted a hydrau l i c p r e s s which app l ies the p r e s s i n g load. The p r e s s u r e in the p r e s s i s gene ra t ed with a NG-60 manual hydrau l ic pump. The rod t r a n s m i t t i n g the p r e s s u r e to the pa r t in the furnace p a s s e s through a vacuum sea l .

The furnace i s suppl ied with a c u r r e n t f rom a 380-V ac power sys t em. The c u r r e n t flowing to the heat ing e l emen t p a s s e s through an OSU-80/0.5 t r a n s f o r m e r , the p r i m a r y c i r c u i t of which i n c o r p o r a t e s an AOMK-100/0.5 regula t ing a u t o t r a n s f o r m e r . The evacuat ion s y s t e m of the furnace cons i s t s of an N-5S oil v a p o r pump, a VN-IMG p r e l i m i n a r y vacuum pump, a carbon b lack and g raph i t e t r ap , s ea l s , va lves , and piping.

The furnace i s p rov ided with an inspec t ion window, which enab les the p r e s s i n g p r o c e s s to be observed and the t e m p e r a t u r e to be m e a s u r e d . The t e m p e r a t u r e i s m e a s u r e d with an OPPIR-017 rad ia t ion p y r o m e t e r . T e m p e r a t u r e ad jus tment i s p e r f o r m e d by hand. Shr inkage during p r e s s i n g is m e a s u r e d w i t h a spec ia l device .

The hot p r e s s i n g of p a r t s i s ef fec ted in a g raph i t e die of max imum ex te rna l d imens ions D = 110 a n d H = 200 ram. The die i s made of MG graph i t e . The hea t ing-up t ime of the furnace to a t e m p e r a t u r e of

Podol , sk . T r a n s l a t e d f rom Poroshkovaya Meta l lu rg iya , No. 5 (101), pp. 97-99, May, 1971. Or ig ina l a r t i c l e submi t ted Ju ly 14, 1969.

�9 1971 Consultants Bureau, a division of Plenum Publishing Corporation, 227 West 17th Street, New York, N. Y. 10011. All rights reserved. This article cannot be reproduced for any purpose whatsoever without permission of the publisher. A copy of this article is available from the publisher for $15.00.

423

fz

Fig. 1 Fig. 2

Fig. 1. Diagram of installation: 1) VN-IMG pre l iminary vacuum pump; 2) vacuum m e te r sensors ; 3) bellows expansion piece; 4) argon cyl inder 5) oxygen reducing valve; 6) valves; 7) vacuum seal; 8) trap; 9) heating chamber; 10) NG-60 hydraul ic pump; 11) manometer ; 12) hydraul ic p ress ; 13) mechanism for lowering and rais ing bot tom lid; 14) N-5So i lvapor pump.

Fig. 2. Heating chamber: 1) die; 2) heating element; 3) cu r ren t terminal ; 4) upper rod; 5) vacuum seal; 6) lining; 7) shell; 8) bot tom lid; 9) inspection window.

2000~ with maintenance of an effective vacuum is 1 h. With the furnace at 2000~ the input is 40 kW. Cooling down f rom 2000~ takes 4 h in a vacuum and 2 h in argon.

Extensive exper ience with the use of GPV-1 instal lat ions has demonst ra ted the i r re l iabi l i ty in opera- tion and efficiency.

1. 2. 3. 4.

5.

6, 7.

L I T E R A T U R E C I T E D

M. T. Vasil ,ev, in: Powder Metal lurgy, Tr . VNITOM, Metal lurgizdat , Moscow, (1954). N. I. Naiguz and D. S. Mil,shtein, Poroshkovaya Met., No. 3 (1962). A. N. I>ilyugin and V. S. Makeev, lhek t ro te rmiya , No. 69 (1968). V. A. Sechko, Hot P re s s ing of Hard Alloy Powders with Induction Heating of Dies [in Russian], Subject 2, M61-502/7, TsITt~IN (1961). I. M. Fedorchenko and N. V. Kostyrko, A Hot P ress ing Instal lat ion, Information Le t t e r No. 12, Inst i- tute of Powder Metal lurgy and Special Alloys, Academy of Sciences of the Ukrainian SSR [inRussian], Izd-vo AN USSR, Kiev (1958). V. S. Makeev, A. N. Pilyugin, et al., Poroshkovaya Met., No. 3 (1969). V. S. Makeev, D. I. Polyakov, and A. N. Pilyugin, E lek t ro te rmiya , No. 60 (1967).

424