Effect of dynamic strain aging on the leak-before-break analysis in SA106 Gr.C piping steel

Effect of test temperature on fracture toughness of modified 9Cr–1Mo steel

“…Previous investigations16 – 21 show varying effects of DSA on the fracture toughness of different materials. Murty et al 16 – 18 have reported decrease in fracture toughness in commercial steels due to DSA, while a beneficial effect of DSA on fracture toughness J 1C has been reported for Armco iron 19.…”

“…Murty et al 16 – 18 have reported decrease in fracture toughness in commercial steels due to DSA, while a beneficial effect of DSA on fracture toughness J 1C has been reported for Armco iron 19. Kim and Kim 20 20,21 reported 30–40 decrease in the initiation toughness J i and d J /d a values in the DSA region compared to room temperature values for a grade SA 106 piping steel. However, the influence of DSA on J 1C was not observed in A516 grade steel,32 as the toughness was observed to decrease continuously with test temperatures.…”

“…In plain 9Cr–1Mo steel dynamic strain aging (DSA) has been reported14 to occur in the temperature range 523–723 K. The manifestations of DSA in tensile tests include serrations, negative strain rate sensitivity, a maximum or peak in variation of flow stress and workhardening rate with temperature and a ductility minimum 15. Previous investigations16 – 21 show varying effects of DSA on the fracture toughness of different materials. The possible effect of DSA on fracture toughness of P91 steel has been examined.…”

Microstructure and dynamic strain aging phenomena in two structural steels

“…Thus, the maximum difference in the ductility between the two steels occurs at the temperature where the workhardening for AISI 403 is the highest. As the uniform ductility for Cr-Mo-V-Ni 2 Plot of yield strength, UTS and ductility as function of temperature for a low alloy steel and b AISI 403: shaded rectangle shows temperature range for DSA observed for two steels 12,15 steel remains relatively constant in the temperature range 250-350uC (Fig. 2a), it clearly implies that the there has been greater embrittlement of AISI 403 as compared with the Cr-Mo-V-Ni steel.…”

“…These studies have shown that there is also a reduced resistance to crack initiation and growth as a result of the operation of DSA phenomena. [8][9][10][11][12][13] In conventional structural steels for component applications in power plants, conditions during sevice (i.e. temperature and strain rate) can be favourable for DSA to manifest in an embrittling fashion due to jerky dislocation motions, collective motion of dislocations and strong obstacles such as precipitates.…”