IGSCC of non-sensitized stainless steels in high temperature water

An EBSD Study of the Deformation of Service-Aged 316 Austenitic Steel

“…where N (θ [2][3][4][5][6][7][8][9][10][11][12][13][14][15] ) is the number of misorientations with angles between 2°-15° and N (θ >2 ) is the total number of misorientations in the orientation map with angles > 2°. The experimental results showed that the evolution of low angle misorientations with the increase in plastic strain was well represented by including a misorientation range of 2°-15° (see section 3.5) and the angular resolution of an EBSD system which uses a Hough transform to detect lines in the patterns is less than 1° [31] , so with proper EBSD system optimization it is possible to determine all misorientations above 2° absolutely.…”

“…AISI type 316 austenitic stainless steel is widely used in power plants because of its good high temperature strength, oxidation and creep resistance [1,2] but long term exposure to temperatures above 823K during service can degrade its mechanical properties [3] and plastic strain can increase its susceptibility to stress corrosion cracking [4][5][6]. Predictions of a plant's remaining safe operating life require reliable methods of determining the inelastic strain levels already reached in safety critical 316 steel components and good models of the operative deformation mechanisms.…”

Avaliação da suscetibilidade à corrosão sob tensão da ZAC do aço inoxidável AISI 316L em ambiente de reator nuclear PWR

“…Por outro lado, tomava-se como base que os aços inoxidáveis austeníticos não eram suscetíveis à CST quando submetidos às mesmas condições de operação. Contudo, recentemente, tem sido reportado que estes materiais sofrem degradação por CST em água hidrogenada e desaerada de modo similar à observada nas ligas de níquel 600, 82 e 182 [12,13].…”

“…À 303ºC foi observada a presença de pequenas regiões esparsas com aspecto frágil e nos ensaios à 325ºC, trincas transgranulares, iniciadas na superfície externa, se propagaram para o centro dos CPs em várias regiões, chegando a uma profundidade máxima de cerca de 500 µm. Segundo Andresen [12] e Ishiyama [24], tanto os aços inoxidáveis sensitizados quanto os não sensitizados podem sofrer CST em ambiente de reator PWR, mas a morfologia das trincas apresentadas pelos aços inoxidáveis não sensitizados é geralmente transgranular. Desta forma, considera-se que a ZAC do aço AISI 316L não sofreu sensitização significativa no processo de soldagem.…”

Experimental and numerical investigation of stress corrosion cracking of sensitized type 304 stainless steel under high-temperature and high-purity water

“…Many studies on crack initiation [24,25] and crack growth [26][27][28][29] have been carried out on materials exposed to high-temperature water, which is simulated environment in boiling water reactors (BWRs) and pressurized water reactors (PWRs). Andresen et al [26] evaluated crack growth of non-sensitized stainless steel in high-temperature water, and reported the effects of yield stress and corrosion potential on crack growth. Kaji et al [27] conducted in-core irradiation-assisted stress corrosion crack growth test using type 304 stainless steel in simulated BWR high-temperature water in Japan Materials Testing Reactor (JMTR) and evaluated the influence of neutron irradiation on crack growth rate.…”