Cold upsetting is a forging method of upsetting (usually local upsetting) metal bars at room temperature. It is usually used to make the head of screws, bolts, rivets, etc. Cutting can be reduced or replaced.

Forging blank materials can be copper, aluminum, carbon steel, alloy steel, stainless steel and titanium alloy, and the material utilization rate can reach 80 ~ 90%. Cold heading is mostly carried out on a special cold heading machine, which is convenient to realize continuous, multi station and automatic production. The cold upsetting machine can sequentially complete the processes of cutting, upsetting, accumulation, forming, chamfering, thread rolling, diameter reduction and edge cutting. The production efficiency is high, up to more than 300 pieces / min, and the diameter of the maximum cold heading workpiece is 48 mm. The bar is automatically fed into a certain degree by the feeding mechanism, cut into blank by the cutting mechanism, and then sent to the accumulation forming and punching station for cold upsetting by the clamp transmission mechanism.

This technology belongs to a kind of cold forming, which is the processing method of punching, shearing, bending and stretching materials without heating. Cold forming processes include cold heading, cold rolling, etc.

Main advantages of cold formed steel structure:

1. Cold formed steel can be processed for smaller loads and shorter spans than thicker hot-rolled sections.

2. Through cold forming, unusual section shape can be obtained economically and satisfactory strength weight ratio can be obtained.

3. Considering the tight type of packaging and transportation, nested sections can be produced.

4. There is no expansion and deformation under the action of environmental gravity.

Cold work hardening:

The processing of steel at room temperature or below recrystallization temperature can significantly improve the strength and hardness, reduce the plasticity and impact toughness, and become cold work hardening.

The process of rolling steel after heating and controlling it above the recrystallization temperature is called hot rolling. The process of rolling below the recrystallization temperature, including normal temperature, is called cold rolling. Hot rolled steel has good plasticity and is easy to form. After forming, the steel has no internal stress, which is convenient for the following processes. Cold rolled steel has the characteristics of cold work hardening. Because cold rolling has good mechanical properties, many directly used steels use cold rolled steels.