外面応力腐食割れ(ESCC)の感受性抽出の スクリーニング方法 …

1 (ESCC) .. 90% . (ESCC).. 50 .. 150 .. 150 800 .. 118 . 30 ESCC .. Relationship of damage mechanisms that became the leakage over 30. years in the petrochemical plant Safety Tomorrow 14. ESCC . ESCC .. SUS-304 . ESCC .. ESCC M/H .. ESCC .. ESCC .. ( ) .. The relationship between the stress corrosion cracking and rain waer retention area under the insulation materials 15 Safety Tomorrow . The relationship between the rainwater retention and corrosion with ESCC of equipment .. DFR(Decreasing Failure Rate) . ESCC .. SCC 100 MPa . CFR (Constant Failure Rate) IFR. (Increasing Failure Rate) . Safety Tomorrow 16.. 12. Bathtub curve es mated 10. DFR. 8 IFR. CFR. 6. 4. 2. 0. 0 10 20 30 40 50.. Relationship of Detected years and equipment wall thickness of the ESCC. m IFR. ESCC ESCC. [1] .. DFR m . 20 CFR m . 21 IFR. DFR (m) . CFR ESCC . IFR .. m . ( ) . [1].. t . F =1 exp ( ) .. F .. (year) ESCC SUS-304. ( ;250N/mm2) .. m ESCC .. m DFR ESCC [2]. m= CFR KISCC.

2 17 Safety Tomorrow . Weibull analysis of ESCC that have been detected during the service period . da/dt ( ) . [3][4][5][6]. ESCC . da =f (K )=AK .. dt a a . F ( ) DFR CFR. ( ) IFR .. t da t ESCC . F =. dt=. i AK .. t 1 da = . i A( /E(k)) a a .. a a . = .. ESCC . A( /E(k)) (1 /2). a/c= DFR .. E(k) 1+ (a/c).. = .. ESCC . a F . ( ) a .. a = a +F A( /E(k)) (1 /2) .. ( ) . DFR . CFR IFR ESCC . a/c= . [2]. a . ESCC . Safety Tomorrow 18. 6 Legend y 5 y y Depth of Cracks (mm). 4. 3. 2. 1. 0. 1 10 100. age Crack propagation rate of ESCC(calculated values). ESCC .. 20 ESCC .. + . ESCC .. 118 .. ( ) .. mm/ mm . ESCC .. SUS-304 .. (M/H . T ) .. 19 Safety Tomorrow . Damage cases of ESCC under high stress environment in between the support shoe and the longitudinal welding of pipes .. С . э .. э э .. y .. э . э . y .. Screening and sensitivity extraction flow chart of ESCC(SUS-304 only). ESCC .. [7] .. - .. ESCC . Safety Tomorrow 20.. / [cm3/cm3]. 0. 0 1 2 3 4 5 6.

3 [ ].. (1983, ). (PREN) 34 [2] . SUS304.. CFR IFR . 70 . 12 (2006) [3] . ESCC ( ) [8]. [4] ( ) . ( ) [5] ( ) ( ). [6] JPI- 8R-12-2003 ( ) [7] . ESCC .. Zairyo-to-Kankyo, 57, ESCC 188-193 (2008) [8] F,B.. 285 . [1] ; ( ) 21 Safety Tomorrow.