Volume 14, Issue 5 (September 1986)
Investigation of Dynamic JId for Alloy Steel Weldments Using the Split Hopkinson Bar
The fracture toughness parameter JId, under dynamic loading conditions, was determined for weldments of HY80 and QT28 alloy steels using a split Hopkinson bar technique. JId was obtained for the fusion zone, the heat-affected zone, and the base metal for these steels as a function of temperature in the range of −80 to 25°C and at loading rates of ˙K = 106 MPa√m s−1. Wedge loaded compact tension specimens were loaded in a split Hopkinson bar. The onset of stable crack growth was determined by using a strain gage that was attached ahead of a fatigue crack. The results show that, at −80°C, fracture with limited stable crack growth takes place, while for all other testing conditions considerable ductility precedes fracture of these alloys.