1. Smelting
1.1 For the production of forged parts, alkaline electric arc furnace smelting followed by external refining is recommended for steel ingots. Other methods ensuring quality can also be used for smelting.
1.2 Prior to or during the casting of ingots, the steel should undergo vacuum degassing.
2. Forging
2.1 The main deformation characteristics during the forging process should be indicated in the forging process diagram. Sufficient allowance for cutting should be provided at the upper and lower ends of the steel ingot for ensuring that the forged part is free from slag inclusions, shrinkage cavities, porosity, and severe segregation defects.
2.2 The forging equipment should have sufficient capacity to ensure complete penetration of the entire cross-section. The axis of the forged part should align as closely as possible with the axial centerline of the steel ingot, preferably selecting the end of the steel ingot with better quality for the turbine drive end.
3. Heat treatment
3.1 Post-forging, normalizing and tempering treatments should be carried out.
3.2 Performance heat treatment should be performed after rough machining.
3.3 Performance heat treatment involves quenching and tempering and should be conducted in a vertical position.
3.4 The heating temperature for quenching during performance heat treatment should be above the transformation temperature but not exceed 960 ℃. The tempering temperature should not be below 650 ℃, and the part should be slowly cooled to below 250 ℃ before removal from the furnace. The cooling rate prior to removal should be less than 25 ℃/h.
4. Stress relieving treatment
4.1 The stress relieving treatment should be performed by the supplier, and the temperature should be within 15 ℃ to 50 ℃ below the actual tempering temperature. However, the temperature for stress relieving treatment should not be below 620 ℃.
4.2 The forged part should be in a vertical position during the stress relieving treatment.
5. Welding
Welding is not allowed during the manufacturing and packaging processes.
6. Inspection and testing
The equipment and capability for conducting tests on chemical composition, mechanical properties, ultrasonic inspection, residual stress, and other specified items should comply with relevant technical agreements and standards.
Post time: Oct-24-2023
