(19) |
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(11) |
EP 0 144 907 A3 |
(12) |
EUROPEAN PATENT APPLICATION |
(88) |
Date of publication A3: |
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05.11.1986 Bulletin 1986/45 |
(43) |
Date of publication A2: |
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19.06.1985 Bulletin 1985/25 |
(22) |
Date of filing: 28.11.1984 |
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(84) |
Designated Contracting States: |
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DE FR GB |
(30) |
Priority: |
05.12.1983 JP 22832783
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(71) |
Applicant: NISSAN MOTOR CO., LTD. |
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(72) |
Inventors: |
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- Jimbo, Yoshio
()
- Sayashi, Mamoru
()
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(54) |
Method of producing austempered spheroidal graphite cast iron body |
(57) 57 An excellently austempered spheroidal graphite cast iron body, which may be a
thick-wall body, is obtained by using a spheroidal graphite cast iron composition
consisting essentially of 3.0-4.0 wt% of C, 1.5-3.0 wt% of Si, 0.3-0.8 wt% of Mn,
0.3-2.0 wt% of Cu, 0.005-0.2 wt% of a spheroidizing agent such as Mg, Ca or Ce, 0-0.1
wt% of Mo, 0-0.3 wt% of Ni and the balance of Fe, and by accomplishing the cooling
of the cast iron body from the austenite stabilizing temperature to the bainite transformation
temperature at an adequate cooling rate so as to avoid precipitation of pearlite,
preferably at a cooling rate between 10°C/sec and 0.64°C/sec. Best results are obtained
by performing the cooling in a fluidized bed furnace.