| Project/Area Number |
06650807
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Material processing/treatments
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| Research Institution | Osaka Prefecture University |
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Principal Investigator |
KAWAMOTO Makoto Osaka Prefecture University, College of Engineering, Professor, 工学部, 教授 (40081369)
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| Co-Investigator(Kenkyū-buntansha) |
IKENAGA Akira Osaka Prefecture University, College of Engineering, Assistant Professor, 工学部, 講師 (60128759)
TSUJIKAWA Masato Osaka Prefecture University, College of Engineering, Associate Professor, 工学部, 助教授 (90172006)
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| Project Period (FY) |
1994 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1996: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1995: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1994: ¥900,000 (Direct Cost: ¥900,000)
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| Keywords | High alloyed iron / Hot rolling mill / Quenching / Secondary temper hardening / Retained austenite / Wear / Rolling fatigue / 炭化物 |
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| Research Abstract |
The heat treatment and the wear resistance under unlubricated rolling-and-sliding condition and lubricated rolling condition of high-alloyed irons (the white iron of high-speed steel type) were investigated. The carbide forming elements, 6mass%Cr, 2mass%Mo, 4mass%W and 6mass%V,were added to irons and the carbon content was varied from 1.5mass% to 2.5mass%. 4mass% or 8mass%Co was also added to the 2.0mass%C iron to strengthen the matrix structure. These irons were melted in a high-frequency furnace and cast in a sand mold. Results were summarized as follows.
(1) The matrix structure transformed to martensite by quenching of austenitizing temperature of 1373K and cooling rate 5-10K/min, and the secondary temper hardening occurred sufficiently by tempering at 823K.The secondary temper hardening was insufficient in the case of quenching from 1273K.
(2) The amount of carbides increased and the as-cast hardness became high with the carbon content of iron. However, the hardness of 2.5%C iron was lower than 2.0%C iron at the secondary temper hardening. This is due to that carbon and alloying elements in the martensite decreased with the carbon of iron.
(3) By addition of Co to iron, its quenching properties naturally deteriorated and the hardness of the quenched atructure decreased, but MC type carbide became granular and M_2C,M_6C and M_7C_3 being small : besides, the secondary temper hardening appeared remakably and the retained austenite became stable.
(4) The wear resistance under unlubricated rolling-and-sliding was considerably improved by adding 8mass%Co to the iron.
(5) The rolling fatigue life of the white iron of high-speed steel type under lubrication was about 10 times as long as high Cr white iron. The white iron became particularly excellent by adding 8mass%Co.
(6) The addition of Co improved the wear resistance of the white iron of high-speed steel type. However, a small amount of Co addition was ineffective and Co over 8mass% should be necesarry to improve.
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