PRODUCTION AND EQUIPMENT
HYDROSTATIC PRESSING OF POWDER MATERIALS IN RUSSIA —
A 50-YEAR-LONG HISTORY
G. A. Il’in
Translated from Novye Ogneupory, No. 11, pp. 12 – 18, November, 2005.
Original article submitted September 22, 2005.
A brief survey of the 50-year long history of the development of hydrostatic molding technologies in Russia is
given. Types of hydrostats and major manufacturing processes used in the refractory industry are described.
The early experiments with hydrostatic pressing of pow-
dered materials into components and preforms started in the
Soviet Union in the mid-1950s. By that time, at the Luga
Abrasive Plant (Leningrad Region), a new technology was
developed that later became known under the name “dry
bag” method. A development shop was organized where cru-
cibles of diameter up to 700 mm and tubes and molds of
height up to 2000 mm were manufactured by this method
(until now in service). A schematic of the pressing chamber
of an early “dry-bag” hydrostat designed for molding cruci
bles from chamotte-graphite materials is shown in Fig. 1.
The pressing chamber looked like a thick-walled cylinder.
The axial load of 10 MN is transmitted in the top section
through a bayonet gate to the to the bottom which is closed
with a conical plug. The elastic pressing shell (rubber) was a
dead-end tube with a wall thickness of 5 mm. A shortcoming
of the hydrostat was the rather low pressure ( p = 20 MPa),
which was not sufficient for high-quality products.
Simultaneously, at the I. P. Bardin Central Research In
stitute for Ferrous Metallurgy (CRIFM) (Moscow), a hydro
stat was designed for pressing refractory powders of tungsten
and molybdenum by the “wet-bag” method. A schematic of
the pressing chamber for hydrostat is shown in Fig. 2. The
inner diameter of the working chamber was 600 mm, and the
height was 1100 mm. The pressing chamber was a frame-like
structure composed of four columns and two stationary
cross-arms. The container was a double-layer cylinder equip
ped with an inner bushing onto which rings were mounted in
interference fit. An intermediate plate moved by means of a
special cylinder was installed between the top plug and the
cross-arm. The high-pressure hydraulic drive was a pump
operating at a pressure p = 100 MPa.
Based on CRIFM results, a shop was put in service at the
Novo-Tul’skii Metallurgical Plant (Tula, Russia) designed
for production of preforms from tungsten and molybdenum
powders. The shop had three hydrostats with working cham-
bers of diameter 230, 400, and 700 mm and height 1200 mm.
The pressing chamber was a thick-walled cylinder (Fig. 3).
The axial load was taken up by a bayonet gate in the top sec
Refractories and Industrial Ceramics Vol. 47, No. 1, 2006
1083-4877/06/4701-0014 © 2006 Springer Science+Business Media, Inc.
Izostat Production Cooperative, Moscow, Russia.
Fig. 1. Schematic diagram of the pressing chamber of a hydrostat
(designed at the Luga Abrasive Plant): 1 ) container; 2 ) bayonet
gate; 3 ) threaded plug; 4 ) thrust bushing; 5 ) core; 6 ) elastic shell;
7 ) perforated arrester; 8 ) conical plug.