Neutron Bragg-edge transmission imaging for microstructure and residual strain in induction hardened gears

Abstract A time-of-flight Bragg-edge neutron transmission imaging was used to investigate the microstructure and strain distributions in a gear hardened by newly developed two-step induction-heating method: precursor (Sample 1) final product 2). The edge-position edge-broadening were determined mapped with high spatial resolution, which enabled us confirm two-dimensional of residual strain. deep layer made for Sample 1 martensite formed on entire teeth outer peripheral portion body. 2 subjected double induction-hardening, where tempered as thermal refined between fine-grained at tooth surface ferrite-pearlite core. relationship Vickers hardness described linear equation employed derive elastic map revealed that steep compressive introduced into super rapid quenching process. reversal tension speculated occur below mm from tip, almost zero core region.