• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.352-357
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• 2003

Creep tests for Titan were carned out using constant-load at $600^{\circ}C$, $650^{\circ}C$ and $700^{\circ}C$. Material constants necessary to predict creep life were acquired from the experimental creep data. And the applicability of Monkman-Grant(M-G) and modified M-G relationships was discussed. It was discovered the log-log plot of M-G relationships between the rupure time(tr) and he minimum creep rate(${\varepsilon}_m$) was conditional on test temperatures. The slop of m was 2.75 at $600^{\circ}C$ and m was 1.92 at $700^{\circ}C$. However; the log-log plot of modified M-G relationships between $t_r/\varepsilon_r$ and $\varepsilon_m$ was indpendent on stresses and temperatures. That is the slop of m' was almost 3.90 in all the data. Thus, change M-G relationships to creep life prediction could be vtilized more reasonably than that of M-G relationships for type Titan. It was divided that the constant slopes never theless of temperatures of practical stresses in the modified relationship were due to an intergranular break grown by wedge-type cauities.

• 대한기계학회논문집A
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• 제24권9호
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• pp.2326-2333
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• 2000

Creep tests for type 316L(N) stainless steel were carried out using constant-load creep machines at 55$0^{\circ}C$, 575$^{\circ}C$ and $600^{\circ}C$. Material constants necessary to predict creep rupture time were obtained from the experimental creep data. And the applicability of Monkman-Grant(M-G) and modified M-G relationships was discussed. The log-log plot of M-G relationship between the rupture time($t_r$,) and the minimum creep rate ($ $\varepsilon$ _m$) was dependent on test temperatures. The slope of m was 1,05 at 55$0^{\circ}C$ and m was 1.30 at $600^{\circ}C$. On the other hand, the log-log plot of modified M-G relationship between $t_r/$\varepsilon$_r$, and $ $\varepsilon$ _m$ was independent on stresses and temperatures. That is, the slope of m＇ was approximately 1.35 in all the data. Thus, modified M-G relationship for creep life prediction could be utilized more reasonably than that of M-G relationship for type 316L(N) stainless steel. It was analyzed that the constant slopes regardless of temperatures or applied stresses in the modified relationship were due to an intergranular fracture grown by wedge-type cavities.

• 한국기계기술학회지
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• 제13권4호
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• pp.125-130
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• 2011

Technological mode progress demands the use of materials at high temperature and pressure. Constant load creep tests have been carried out over the range of stresses at high temperatures. One of the most critical factors in considering such applications as the most critical one is the creep behavior. In order to investigate the creep behavior in this study, the stress exponents during creep were determined over the temperature range of $275^{\circ}C$ to $325^{\circ}C$ and the stress range of 36MPa to 72MPa. The applicability of modified Monkman-Grant relationship was also discussed.