Characterization of residual stress and texture in cast steel railroad wheels

Residual stress and texture were characterized in the rim of a cast steel railroad wheel, using both an electromagnetic acoustic transducer (EMAT) and a piezoelectric transducer. Orthogonally polarized shear horizontal waves were propagated through the thickness of the rim, and arrival times measured (by the pulse-echo method) with a precision of ≈ 10 −5. The difference in arrival times (birefringence) is related to the difference in principal stresses and also to texture. The wheel had been sawcut in a previous experiment and the residual stress had been relieved at the sawcut. The birefringence was measured at the sawcut and subtracted from the birefringence measured at stressed regions. This allowed us to map variations in stress around the circumference of the wheel. Stresses measured with the EMAT and piezoelectric transducer agreed to within 10 MPa.