In metal processing, forging is a common processing method, and forging release agent is an essential auxiliary material in the forging process. Below, we will briefly understand the relevant content.
Forging technology belongs to the volumetric forming process of metal materials. During the forming process, the contact pressure between the metal material and the surface of the mold (tool) is very high, and the plastic deformation of the material is large, resulting in a large amount of new surfaces. Therefore, the wear of the forged mold, the surface condition of the product, and residual lubricants are always constantly changing. The lubrication condition has a significant impact on the forging process. In order to improve the quality of workpieces and reduce production costs, it is necessary to continuously develop new release agents to meet the constantly improving forging processes and requirements.
The effective lubrication of the mold by the release agent in forging processing can improve the flow and forming performance of the metal in the mold, ensure that the forging is full, reduce forging force, reduce mold wear, improve mold service life, prevent mold jamming, and have the equivalent effect of reducing heat and demolding
The forging process is divided into cold forging (forging directly at room temperature), temperature range (workpiece temperature not exceeding the metal recrystallization temperature, generally between 300 ℃ -800 ℃), and hot forging (workpiece temperature exceeding the metal recrystallization temperature, generally above 800 ℃) according to the temperature of the metal material during forging; According to the use of molds in the forging process, it can be divided into free forging (a forging method that does not use molds and is usually applied to large workpieces), die forging (which can be divided into open die forging and closed die forging). Generally, small and medium-sized forgings use bar materials as raw materials, which have uniform grain structure, good mechanical properties, accurate shape and size, good surface quality, and are convenient for mass production.
Cold forging
The workpiece undergoes deformation and work hardening during cold forging, causing the forging die to bear high loads, thus requiring the use of high-strength dies and lubricating films to prevent wear and adhesion. The most successful lubrication method currently is to perform a "phosphating saponification" treatment on the surface of the workpiece. Phosphating is the use of chemical methods to generate porous thin films of zinc phosphate and iron phosphate on metal surfaces, with a thickness of 10-25 microns and a low coefficient of friction. This phosphating film can store lubricants, which can serve to isolate the workpiece from the mold during forging and reduce the friction between the workpiece and the mold. Saponification is a lubrication treatment method that uses fatty acid soap as a lubricant to chemically react with zinc phosphate in the phosphating layer to produce zinc stearate. For example, after phosphating treatment on the surface of carbon steel parts, saponification solution is used as a lubricant.
Hot forging
In the hot forging process, a good release agent is an important auxiliary material to ensure the quality of precision forgings. Generally, graphite type release agents are mainly used, including oil-based graphite and water-based graphite. Considering the reduction of smoke and improvement of operating environment, water machine graphite has been widely used. Titanium nickel alloys and high melting point metals often use glass release agents because glass has a protective effect against oxidation and a thick film lubricating effect.
Warm forging
Warm forging combines the advantages of both cold forging and hot forging, with less deformation force, lower workpiece temperature, and better surface quality than hot forging. During the warm forging process, the temperature of the workpiece does not decrease significantly, so multiple deformation processes can be completed on one press without intermediate treatment. Due to the high load borne by the mold during warm forging and continuous operation at high temperatures, the hardness of the mold decreases significantly, resulting in a decrease in the wear resistance of the mold. The purpose of the release agent for warm forging is to fully cool the mold, maintain the appropriate temperature of the mold, prevent the mold temperature from being too high, and reduce the hardness of the mold. Secondly, it reduces the friction and wear of the mold, lowers the processing load, improves the life of the mold, and ensures product quality. The most widely used is graphite type release agent. Nowadays, new types of non graphite type release agents have emerged in the market, which can also achieve the desired effect, avoid environmental pollution, and prevent damage to equipment caused by graphite conductivity.
