How to select raw materials for cold heading process.

Cold heading machine is a special equipment, which is mainly used for mass production of nuts, bolts and other fasteners. Most of them are heavy equipment that exerts pressure on metals, and most of them are equipped with safety protection devices to ensure the safety of equipment and personnel. The chemical composition and mechanical properties of raw materials for cold heading of cold pier machine should meet the relevant standards of multi-station automatic cold heading machine. Common raw materials are copper-aluminum alloy, carbon steel, stainless steel and other materials. Here is a brief introduction on how to select raw materials for cold heading process:

I. Selection of raw materials for workpieces

(1) raw materials must be spheroidized and annealed, and its metallographic structure is spherical pearlite.

(2) In order to reduce the cracking tendency of the material as much as possible and improve the service life of the die, the hardness of the raw materials is also required to be as low as possible to improve the plasticity.

(3) The inch accuracy of raw materials should generally be determined according to the specific requirements and process conditions of the workpiece. Generally speaking, the multi-station cold heading machine has low requirements on the dimensional accuracy of shrinkage and strong shrinkage.

(4) The surface quality of raw materials requires the lubricating film to be dull, and the surface shall be free of scratches, folds, cracks, galling, rust, scale, pits and other defects.

(5) It is required that the total thickness of the radial decarburization layer of raw materials shall not exceed 1% of the diameter of raw materials.

(6) In order to ensure the cutting quality during cold forming, it is required that the surface of raw materials is hard and the center is soft.

(7) Raw materials shall be subjected to cold heading test to increase deformation resistance due to cold working and hardening. The lower the sensitivity of materials to cold work hardening, the better.

Second, the choice of cold heading forming oil

(1) has excellent extreme pressure lubrication performance, high temperature resistance, extreme pressure wear resistance, rust resistance and high temperature oxidation stability. Improve the accuracy and smoothness of the workpiece, prevent the mold from sintering, meet the multi-station forming processing of standard parts and non-standard parts, and be fully qualified for cold heading stainless steel workpieces.

(2) It can minimize the oil smoke and "floating fog" and meet the nut process of strong die shrinkage.

(3) It has good performance for workpieces with large deformation, such as hollow, high-strength bolts, sleeves, stainless steel hollow and semi-hollow rivets.

(4) It can effectively protect the punch (punching needle) and the die, and prolong the service life.

(5) The heat dissipation effect is good, and the local temperature of the workpiece and the mold is prevented from being too high in the cold forming process.

(6) It is resistant to high temperature and is not easy to produce sludge. Low odor and smoke, protecting the operating environment.

(7) It has certain rust resistance and can meet the requirements of rust prevention between processes.

(8) It can meet the demanding forming process of large deformation cold heading stainless steel and carbon steel.

The above is the selection method of raw materials for cold heading process. Using raw materials that meet the process requirements can effectively avoid quality problems of workpieces.