Ductile Fracture Behavior of ASTM A516 Gr.70 Pressure Vessel Steel by ASTM and ISO Fracture Toughness Standards

Fracture toughness determination is crucial for the design phase of pressure vessels, and, although ASTM E1820 and ISO 12135 fracture toughness standards have existed for some time, some differences have been reported in the determination of this property. This study investigates the ductile fracture behavior of ASTM A516 Gr.70 pressure vessel steel and assesses the differences in estimating both standards. The steel's tensile properties and initiation fracture toughness (J(IC)) were evaluated, taking into account the parallel and perpendicular orientations to the rolling direction. The results reveal the properties' dependence on the rolling direction, mainly attributed to perlite banding. Additionally, as for the J(IC) determination, the differences were associated with the different blunting line slope estimations on each standard, reinforcing the necessity of a work-hardening-based blunting line for each material assessed.

Automated summary

In this study, the ductile fracture behavior of ASTM A516 Gr.70 pressure vessel steel was investigated, and the differences in estimating ASTM E1820 and ISO 12135 standards were assessed. The results showed that the mechanical properties and fracture toughness of the steel were dependent on the rolling direction, mainly attributed to perlite banding. Additionally, the differences in J(IC) determination were associated with the different blunting line slope estimations on each standard, highlighting the necessity of a work-hardening-based blunting line for each assessed material.