The warm forging manufacturing process occurs within the temperature range of 650 °C and 1000 °C, depending on the used material and the components type. This is usually above the work hardening temperature of the workpiece and below the temperature at which scale forms.
Warm Forged Common Rails
If the forging temperature is below the transformation point of 740-770 °C, the material should undergo a preliminary heat treatment. This temperature range is used for parts with medium complexity which don’t require heat treatment after forging. For parts with greater complexity, the forging temperature is above the transformation point.
Although this temperature range is close to the one of hot forging, in terms of technology warm forging is rather similar to cold forging.
The warm forging process is placed somewhere between the cold and hot forging techniques, combining all their advantages as surface quality, precision, material usage and flexible shapes but generally requires high engineering skills (tools design, cooling, lubrification) and a dedicated forging press.
The information is from www.farinia.com