Volume 3, Issue 2 (February 2006)
Analysis of Creep Crack Initiation and Growth in Different Geometries for 316H and Carbon Manganese Steels
Results obtained from a European collaborative project aimed at producing a draft code of practice for creep crack growth testing are presented. The tests were performed on an Austenitic Type 316H Stainless Steel at 550°C and a carbon manganese steel at 400°C. A range of specimen test geometries has been examined. These are the single edge notched specimen in tension and bending, the double edge notched specimen in tension, the middle cracked specimen in tension, and the C-shaped specimen in tension. The results obtained are compared to those obtained using the standard compact tension specimen following the ASTM Standard Test Method for Measurement of Creep Crack Growth Rates in Metals (E 1457). Creep crack creep growth rates and initiation times have been correlated with the fracture mechanics parameter C*. The applicability of the stress intensity factor K to describe the creep cracking behavior is also assessed. Recommendations are made to support the use of different geometries in creep crack growth and/or creep crack initiation testing.