SB-06-1(012) The Effect of Microstructural Morphology of Steel on Threshold Stress in Creep(Changes in Microstructure 1)

スポンサーリンク

概要

• 論文の詳細を見る

• High temperature strengthening mechanisms under various microstructural morphologies were examined by performing a close comparison between the creep behavior of TMCP EH36 and SM490C steel. The two steels were prepared with the same composition but different rolling processes. The equiaxed grain of TMCP EH36 steel was produced by thermo-mechanical control rolling (TMCP) with an accelerated cooling process. The banded structure of SM490C steel was produced using the conventional hot rolling process. The results show that the apparent activation energy and apparent stress exponent in the band structure of SM490C steel were much higher than that in the equiaxed grain of TMCP EH36 steel. The creep stress exponent value from the threshold stress, σ_0, concept in the dispersion strengthening mechanism can explain how the second phase distribution and morphology have an obvious effect on the creep behavior in this study. The data reveal that there are two main differences in creep behavior between the equiaxed grain steel (TMCP EH36) and elongate band grain steel (SM490C). The creep rates of the equiaxed grain are several orders of magnitude faster than those of the banded elongate grain. The activation energy for creep in the equiaxed grain steel is higher than that in the banded elongate grain steel. Analysis of the experimental data indicates that the obvious difference in creep behavior can be explained in terms of the strengthening processes that are related to the existence of a temperature-dependent threshold stress for creep σ_0 in both materials. This finding is illustrated by two results. First, the high apparent activation energies for creep in the SM490C steel with banded elongate grain are corrected to a value near the true activation energy for creep by considering the temperature dependence of the Young's modulus, the threshold stress. Second, the normalized creep data for both steels falls very close to those of an alloy in a creep power law in which the applied stress is replaced by the effective stress, the stress exponent, n , equals 3〜4, and the true activation energy for creep in both steels corresponds to the activation energy of diffusion.

• 一般社団法人日本機械学会の論文
• 2001-06-03

著者

• Wang S.

  Dept. of Mechanical Engineering, National Univ. of Singapore

• Chiang C.

  Dept. Of Mechanical And Marine Engineering National Taiwan Ocean University

• Chan S.

  Institute of Materials Engineering, National Taiwan University

関連論文

• OS1(4)-17(OS01W0437) Micro-Components Evaluation Using Optical Techniques
• SB-06-1(012) The Effect of Microstructural Morphology of Steel on Threshold Stress in Creep(Changes in Microstructure 1)

スポンサーリンク