Hot Forging
Hot forging shapes metal above its recrystallisation temperature, around 1,100–1,250 °C for steel, where it is soft and easy to deform. It allows large deformations and complex shapes with low forming force, and is the most common forging method.
What it is
Billets are heated in induction or gas furnaces and forged immediately. At these temperatures the metal recrystallises continuously, so it doesn't work-harden and can be shaped extensively.
Hot-forged parts have scale and wider tolerances than cold-forged parts, so they are shot blasted and machined as required.
Typical applications
- Crankshafts and axles
- Gears, flanges and hubs
- Connecting rods and levers
- Valve bodies and fittings
- Large and complex forged parts
Suitable materials
- Carbon steels (EN8, C45, 1045)
- Alloy steels (EN19, EN24, 42CrMo4, 20MnCr5)
- Stainless steels (304, 316, 410, 17-4 PH)
- Aluminium, brass and copper alloys
Points to consider
- Allow for scale loss and machining stock.
- Heat treatment after forging sets final properties.
- Suits complex shapes and larger parts.
- Cold or warm forging may be cheaper for small, simple high-volume parts.
Frequently asked questions
What is the difference between hot and cold forging?
Hot forging shapes heated metal for large deformations and complex shapes. Cold forging works at room temperature for better accuracy and finish on smaller parts.
What temperature is steel hot forged at?
Typically around 1,100–1,250 °C for carbon and alloy steels, depending on the grade and the size of the part.
Do hot forgings need machining?
Usually yes, on functional surfaces, because of scale and forging tolerances.