3.1 ForgingTo be carried out by press or roller forging machine capable of working themetal throughout its entire length.3.2 Heat treatmentSolution heat treatment to provide a homogeneous structure with carbidecontent down to a minimum.3.3 Cold work (if necessary)Cold expansion or after slight heating, sufficient to secure mechanicalproperties requested.3.4 Stress reliefAfter cold work, the rings shall be slowly heated to 280° - 350°C, soaked for8 to 12 hours and then allowed to cool slowly to ensure dimensional stability.