A measurement method of residual stress in quenched steel by neutron diffracation

An experimental methodology was developed for identification of residual stresses inside quenched steel by neutron diffraction considering gradient distribution of martensite phases. A hybrid method is used by which the residual stress in the quenched steel was measured with neutron diffraction integrated with numerical simulation results of microstructure and phase distribution. A coupled finite element analysis based on metallo-thermo-mechanical theory was carried out to predict the microstructure due to phase transformation during quenching process. The non-strain lattice spacing and elastic modulus were measured with rotating specimen method in tensile test. Then, residual stresses in the (110) plane are measured using the cylinder specimens of quenched S45C and SCr420 steel by the neutron diffraction method. Finally the measured results of XRD, neutron diffraction as well as the calculated values were compared and discussed.