Shot peening analysis on trip780 steel exhibiting martensitic transformation

The microstructure and mechanical fields were studied on a cold-rolled TRIP 780 steel after conventional shot peening, and with or without pre-strain; for the first time, results were compared to numerical simulations at the phase scale. 1. The pre-strain does not affect residual stresses in the different phases nor the affected depth but it shifts the austenite fraction value towards lower values. 2. All the constituents were found in compression; the maximum value reached in the austenite was -800 MPa while around -500 MPa in the BCC phases. 3. The stress variations are maximum in the zone affected by the martensitic transformation