Effects of Tempering and Test Temperature on the Dynamic Fracture Initiation Behavior of an AISI 4340 VAR Steel

摘要

An investigation was conducted into the effect of tempering, test temperature and loading rate on the fracture initiation behavior of an AISI 4340 VAR steel. The fracture initiation test were conducted by stress wave loading of a prefatigued circumferential crack in a notched round bar. The geometry provides for plane strain conditions at the fracture site, and the instrumentation gives records of average stress at the fracture site and of crack opening displacement, both as functions of time. Keywords: Fracture, 4340 VAR steel, fracture toughness, dynamic effects, temperature effects, microstructural effects. (jes)