Master curve and J-R fracture toughness of SA508/SA533-B-1 weld and HAZ

A large heat of low-alloy steel that met both specifications for SA508 Grade 3 Class1 forging steel and SA533 Type B Class 1 plate steel (A508/A533) was procured and used to fabricate a submerged-arc weldment for potential application in high temperature gas-cooled reactors. Compact specimens, 1TC(T), were machined from the weld metal and from the heat-affected-zone (HAZ) of the weldment. Tests of both materials were performed to obtain the fracture toughness reference temperature, To, using the Master Curve procedure of ASTM E-1921, and J-R curves to evaluate material behavior at various threshold temperatures in Code Case N-499-2 (2001) of the ASME Boiler and Pressure Vessel Code. Tests were performed at various temperatures up to 593°C. Unloading compliance was the primary technique used, although dc-potential drop was also monitored during the tests, and the normalization procedure of E1820 was used to compare the results from each procedure. Moreover, many tests at the highest temperatures were performed with no unloading and the normalization procedure provided in E1820 was used to analyze the load-displacement measurements. The fracture toughness for the HAZ is superior to that of the weld metal both in terms of transition temperature and ductile fracture toughness.