Evaluations of stress-free lattice spacings and residual stresses in a quenched carbon steel cylinder using neutron diffraction

Microstructure-dependent stress-free lattice spacings (d0) were measured using neutron diffraction in a comb-like specimen fabricated from a quenched carbon steel cylinder. The d0 values increased with cylinder radius due to the increase in the martensite (α′) fraction with the radius and were comparable to d0 values calculated using the lattice parameter of each phase, taking the auto-tempering effect into consideration. Using the measured d0 values, we suggested a relationship between the d0 and α′ fraction and evaluated macroscopic residual stresses in the quenched steel cylinder.