Warm / hot forged products:

Cold forging of large size or large deformation parts will give rise to forging defects or require more operations due to metal deformation resistance under room temperature, cold working hardening, limit of equipment capacity, limit of tooling strength, etc. Usually parts no larger than M24 are most suitable for cold forming though we can cold forming M30 screws. For large sizes or parts requiring large amount of deformation, warm forging or hot forging is better.

Warm forging shapes metals at temperatures between room temperature and recrystallisation temperature. To avoid blue brittleness and hot brittleness, carbon steel is usually warm forged between 400℃ - 600℃. In this range of temperature, steel plastic deformation resistance drops and ductility increases. Besides, scaling of surface and decarburization is avoided. So dimensional accuracy, surface roughness and mechanical properties of warm forged parts are similar to cold forged ones while fatigue strength will be better.

Hot forging plastically deforms metals at temperatures above recrystallization points. At such temperatures metals exhibit low deformation resistance and high flowability so low forging force is required. Hot forging is used to form large parts, parts of large deformation volume and materials hard to deform. However, hot forging has several disadvantages.? Tooling temperature rises quickly and cooling is not uniform, so tooling cracks and wears easily and tool life is short. Dimensional accuracy and surface quality are also poor because of the expansion of the hot blank and tooling and blank surface oxidation.

By warm and hot forging, Autocraft can not only produce large size fasteners but also gears, cylinders, bearing collars, universal joints, rear vehicle axles, small motor shells, turbo electric generator sleeve, etc.