Description of Fatigue Crack Growth in Steel Structural Components Using Energy Approach - Influence of the Microstructure on the FCGR.

In this paper, the theoretical and experimental results of fatigue crack growth in AISI 5140 steel have been presented. According to the previous theoretical background - the energy parameter ΔH is introduced as a crack driving force in construction of fatigue crack growth rate (FCGR) diagrams. The physical explanation of this model is also presented. In experimental parts of this work, the kinetics fatigue fracture diagrams (KFFD) for AISI 5140 steel were constructed. The main goal of experimental works was to investigate the influence of microstructure on kinetics of fatigue crack growth. The AISI 5140 steel were tested in three different heat treatment conditions. As it has been confirmed, the energy parameter H describes the kinetics of fatigue crack growth much more synonymously than the classical stress intensity factor - ΔK. [ABSTRACT FROM AUTHOR]