| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2000: ¥100,000 (Direct Cost: ¥100,000)
Fiscal Year 1999: ¥100,000 (Direct Cost: ¥100,000)
Fiscal Year 1998: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1997: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Research Abstract |
Graphite crystallized chromium white cast iron is composed of the three-phase composite structure of carbide, iron matrix, and graphite. The flakily graphite crystallized chromium white cast iron (FG alloy) becomes the spheroidal graphite crystallized type (SG alloy) by the spheroidizing. The deformation of the matrix mainly governed high temperature deformation of these alloys on the high temperature compression test. In the meantime, the strength depended on the property of the carbide. Though compression strength was improved by the graphite spheroidizing at the temperature under Tm/2, in the temperature over Tm/2, it did not change. In addition, the strength hardly lowered by the existence of the graphite, when it was compared in usual high chromium white cast iron. The difference of each alloy was remarkable for the sliding wear resistance by Okoshi type test in the high friction velocity side. The SG alloy was most excellent in the wear resistance, and the order of the following FG alloy and 2.6C-15Cr alloy. FG alloy and SG alloy changed after the heat treatment over HRC60 from HRC44 of as-cast, while it was also about HRC55 in either case, each 2.6C-15Cr alloy. However, the drastic improvement on wear resistance through the heat treatment could not be observed. The relation between wear amount and friction velocity becomes generously the low velocity side for the profile with the peak. In the meantime, these tend to be completely reverse for the friction coefficient, since the low velocity side is minimized. In comparison with normal high chromium white cast iron, graphite crystallized chromium white cast iron is also over par or over it on strength and wear resistant. In addition, it may be able to widely use as an wear-resistant material, because that the graphite keeps the oil in lubricated condition is anticipated. Moreover, both heat-resistance and corrosion resistance seem to be also excellent, since the matrix is retained austenite in the as cast.
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