The present study deals with the short fatigue crack growth behaviour of a ferritic steel (nuclear grade SA 333 Grade 6 steel) weld metal at two load ratios R of 0.1 and –1. Single edge notched weld joint specimens were tested at different stress levels. The acceleration and deceleration in short crack growth with increasing stress intensity factor range was explained in terms of microstructure of weld metal. Acicular ferrite and grain boundary ferrite acted as barriers to crack growth. Non-propagating cracks were observed due to multiple cracks and blocking by ferrite grain boundaries. Transition crack length, the limiting crack length above which the crack exhibited a typical long crack behaviour, was determined to be 1 mm at R=0.1 and 1.5 mm at R=2 1.
Ramesh KumarG., ‘Fatigue crack growth behaviour of a low carbon steel with emphasis on short crack regime’, MS thesis, Indian Institute of Technology, Madras, India, 2002.
20.
GhoshP. K., KushwahaH. S., VazeK. K. and SinghP. K.: in Indo-German Theme Meeting ‘Fatigue and fracture assessment of pressure retaining components’, (ed. B. K. Dutta and H. S. Kushwaha), Mumbai, India, 2002.
SmithR. A. and MillerK. J.: J. Mech. Sci., 1978, 20, 201–206.
31.
LeisB. N. and ForteT. P.: in ‘Fracture mechanics’, Thirteenth Conf., ASTM STP 743, 100–124; 1981, Philadelphia, PA, ASTM.
32.
SugdenA. B. and BhadeshiaH. K. D. H.: Metall. Trans. A., 1989, 20A, 1811–1818.
33.
CarlsonR. L., SteadmanD. L. and KardomatersG. A.: Int. J. Fracture, 2001, 108, 63–72.
34.
RavichandranK. S., LarsenJ. M. and LiX. D.: in Proc. Third Found. Int. Conf. ‘Small fatigue cracks’, Hawaii, 95–108; 1999, Oxford, Elsevier Publications.
35.
PatelA. M., NeuR. W. and PapeJ. A.: Metall. Mater. Trans, 1999, 30A, 1289–1300.
