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1. (WO1979000274) MANUFACTURING PROCESS OF METAL PIECES MADE OF ALLOY CAST IRON EXPOSED TO WEAR
Latest bibliographic data on file with the International Bureau

Pub. No.: WO/1979/000274 International Application No.: PCT/CH1978/000035
Publication Date: 17.05.1979 International Filing Date: 02.11.1978
IPC:
C21D 5/04 (2006.01) ,C22C 37/06 (2006.01)
C CHEMISTRY; METALLURGY
21
METALLURGY OF IRON
D
MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING, OR OTHER TREATMENTS
5
Heat treatment of cast-iron
04
of white cast-iron
C CHEMISTRY; METALLURGY
22
METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
C
ALLOYS
37
Cast-iron alloys
06
containing chromium
Applicants:
Inventors:
Priority Data:
13767/7711.11.1977CH
Title (EN) MANUFACTURING PROCESS OF METAL PIECES MADE OF ALLOY CAST IRON EXPOSED TO WEAR
(FR) PROCEDE DE FABRICATION DE PIECES METALLIQUES EN ALLIAGE DE FONTE FE/CR DESTINEES A ETRE EXPOSEES A L"USURE
Abstract:
(EN) Hitherto metal pieces made of alloy cast iron Fe/Cr and exposed to wear, of which the basic mass had a martensitic character, contained, without any exception, secondary carbide deposits; this was due to the fact that these pieces, once cast, were first cooled to room temperature and, only after, submitted to high temperature treatment for the hardening. On the other hand, the metal pieces intended for exposure to wear and obtained according to the invention are substantially free of secondary carbide deposits; this is achieved as follows: the unmoulding of the moulded cores is done immediately after solidification and without any cooling under the perlite point AC1 ; then, in order to destabilize the austenite, it is kept during five hours at least at a temperature above the perlite point AC1; after, the temperature is gradually lowered until it reaches room temperature, while avoiding, nevertheless, the formation of perlite and bainite. There is substantially no elimination of secondary carbides which cause deterioration of the physical characteristics of the pieces in question. The pieces obtained according to the invention are of improved and more uniform quality and have a higher resistance to deformation, while having the same resistance to wear.
(FR) Jusqu"a ce jour les pieces metalliques en alliage de fonte Fe/Cr destinees a etre exposees a l"usure dont la masse fondamentale presentait un caractere martensitique, contenaient sans exception des depots de carbures secondaires; ceci etait du au fait que ces pieces, une fois coulees, etaient d"abord refroidies a temperature ambiante et soumises seulement par la suite au conditionnement a haute temperature en vue de leur trempe. Par contre, les pieces metalliques destinees a etre exposees a l"usure obtenues selon l"invention ne presentent pratiquement pas de depots de carbures secondaires, ceci se realise de la facon suivante: le demoulage des noyaux moules se fait immediatement apres-solidification et ceci sans refroidissement au-dessous du point perlite AC1; puis, en vue de destabiliser l"austenite, l"on maintient pendant au moins 5 heures une temperature qui se trouve au-dessus du point perlite AC1; par la suite, l"on abaisse la temperature tres progressivement, tout en evitant cependant la formation de perlite et de bainite, jusqu"a temperature ambiante. Il ne s"elimine pratiquement pas de carbures secondaires, qui eux deteriorent les proprietes physiques des pieces en question. Les pieces obtenues selon l"invention sont de qualite amelioree et plus reguliere et presentent une meilleure resistance a la deformation, tout en ayant une resistance a l"usure identique.
Designated States:
Publication Language: German (DE)
Filing Language: German (DE)