The heavy steel plates (100 - 300 mm) require a good geometric stability during the manufacturing operations by end users. This stability depends on the residual stress state inherited from the manufacturing process. This residual stress state is assessed by an ultrasonic testing method : the acoustical birefringence. The first tests carried out on representative heavy plates allowed to define the most suitable measurement configurations and to identify the residual stress states that could generate shape defects. Then, this method was applied to industrial heavy plates with success.