Fracture toughness of carburised M50NiL steel at different tempering temperatures has been investigated using a new evaluation method involving the ‘pop in’ phenomenon which occurs when a crack propagates through the carburised layer. An increase in tempering temperature resulted in an increase infracture toughness, and the rate of increase of the fracture toughness of the core was much higher than that of the surface. The changes in microstructure, residual stress, and retained austenite through the carburised layer were found to be the main factors causing the occurrence of pop in and causing the fracture toughness of the core to be higher than that of the surface.
Get full access to this article
View all access options for this article.
References
1.
G. ‘CRASS: Microstructures and properties of carburized steels’, in ‘ASM handbook’, Vol. 4, 363-375; 1991, Materials Park, OH, ASM International.
2.
LOUB. Z. and AVERBACHB. L.: Metall. Trans. A, 1983, 14A, 1899–1906.
3.
SPITTERP. F.: Ball Bear. J., 1989, 234, 6–11.
4.
FUY. Q., GUY. W., JINGX. T., DuM. L., and LOUB. Z.: Int. J. Fract., 1995, 74, 71–74.
5.
ASTM Standard E399, ‘Standard test methods for plane-strain fracture of metallic materials’, 1983, Philadelphia, PA, ASTM.
