電気化学的手法を用いた2.25Cr-1Mo鋼の経年劣化の非破壊評価

概要

論文の詳細を見る
2.25Cr-1Mo steel is one of heat resistant materials used most widely in fossil power plants as a header and a boiler tube. The most important phenomenon in material deteriorations in 2.25Cr-1Mo steel during a long term operation is carbide coarsening. Carbide coarsening causes such changes in mechanical properties as softening or reduction both of creep strength and of toughness. In this paper, a new nondestructive method for detection and evaluation of these material degardations in 2.25Cr-1Mo steel by means of an electrochemical technique is described. The main results obtained are as follows. (1) A degree of material degradation can be evaluation by the peak value of current density (ΔI_p) obtained by the anodic polarization measurement Since ΔI_p corresponds to the rate of selective dis-solution of coarse carbides M_6C, the amount of M_6C carbides can be evaluated quantitatively by ΔI_p. (2) ΔI_p shows a good correlation with ΔFATT. Hence, the toughness reduction can be nondestructively estimated by AΔI_p measurement. (3) ΔI_p can be regarded as a representative parameter showing the decrease in Mo concentration in grains caused by M_6C (Mo-rich) carbide coarsening. ΔI_p shows a good correlation with hardness change ΔH_v. Based on this interrelation, the degree of softening can be nondestructively estimated. (4) The L. M. P. value of materials used in actual plants can be estimated by ΔI_p measurement Hence, the actual operational temperature can be estimated from the operation period with high accuracy.
社団法人日本材料学会の論文
1991-01-15

電気化学的手法を用いた2.25Cr-1Mo鋼の経年劣化の非破壊評価

スポンサーリンク

概要

著者

関連論文

スポンサーリンク