Free forging is a simple and flexible basic forming method of metal plastic processing. It uses the upper and lower anvil blocks of forging equipment and some simple general tools to make the blank plastic deformation under pressure. Free forging can be divided into manual forging and machine forging. With the rapid development of machine manufacturing industry, machine forging is now mainly used in production. According to different types of forging equipment, machine forging can be divided into hammer free forging and hydraulic press free forging. The former is used to forge small and medium-sized forgings, while the latter is mainly used to forge large forgings.
Because the tools used for free forging are simple, versatile and flexible, they are suitable for the production of single piece and small batch forgings. The free forging is formed by the progressive deformation of the blank, and the tool only contacts the blank part, so the required equipment power is much smaller than the die forging, so the free forging is also suitable for forging large forgings. For example, the 10000 ton die forging hydraulic press can only forge forgings weighing hundreds of kilograms, while the 10000 ton free forging hydraulic press can forge large forgings weighing more than 100 tons. It can be seen that the free forging forming technology can only be adopted for the forging of large forgings.
However, free forging depends on workers' operation to control the shape and size of forgings, so the precision of forgings is poor, the forging productivity is low, and the labor intensity is high. In view of the above shortcomings, in recent years, the free forging production is constantly improving and developing in improving the precision of forgings and realizing mechanization.
The forming process of any forging is composed of a series of deformation processes. Forgings are no exception. Today, let's look at the free forging process of forgings. It can generally be divided into three categories: basic process, auxiliary process and finishing process.
The basic process refers to the process that can greatly change the shape and size of the blank, and it is also the main deformation process in the free forging process. Such as upsetting, elongation, punching, mandrel reaming, mandrel elongation, bending, chopping, staggering, twisting, etc.
Auxiliary process refers to the process of pre deformation before the blank enters the basic process.
Finishing process refers to the process used to finish the size and shape of forgings so that they can fully meet the requirements of the forging drawing. It is generally carried out after a basic operation is completed. For example, after upsetting, the drum and section are rounded, convex, concave and uneven, and the indentation surface is flat, the end face is flat, the bending and straightening after elongation and the correction after skew forging.
During the forming process of any free forging, each of the above three processes can be used separately or combined alternately as required.