Difference Between Cold Forging & Hot Forging?

Not sure about EN19, but hot forging uses metal at a more plastic state due to temperature. Through cooling the metal's properties can be set to make it harder and brittle or softer but stronger.

Cold forging uses powerful hammers or presses to form metal while cold. This method induces stresses within the metal that can cause cracks later, but is usually less expensive to manufacture. Sometimes those stresses are desired in the final product.

Drew K

Thanks.

Sir, actually i have to manufacture M20X50 (grade 8.8 i.e. hardness 22 to 32 HRC, tensile strength 860 N/mm2 min.) screw from EN19 material so which process should i use cold forging or hot forging.

http://en.wikipedia.org/wiki/Thread_rolling#Thread_forming_and_rolling

cold.

Kindly inform us where these screws will be sold.