What is red punching?

Process introduction of Red Punching

"Red punching" is a new name that is not included in the dictionary, and it is also called "warm upsetting" in some places. The red punching process is an advanced professional technology developed from the modern precision forging and hot extrusion foundation.

The red punching process is one of the machining methods for less or no cutting of metal materials. The metal material is heated to a certain temperature and put into the preheated die during red punching. The metal material is plastic deformed by one-off reciprocating movement of the press machine tool, and the required size and good mechanical properties of the compressed parts are obtained.

The red punching process is one of the effective methods to improve the mechanical properties of parts by changing the processing method. The red punching process heats the metal blank in the mold like the precise forging process, the red punching process generally takes one-time forming except large forging parts, but the precision forging usually takes several times. Red punching process compared with the hot extrusion process, the blank need be heated. The hot extrusion die is basically same with the cold extrusion die, the flow of the metal material within the cavity is relatively simple, most of the formed parts are similar to cold extruded parts in shape, tend to be simpler shapes, but the die for red punching is complex structure than the heat extrusion die, The structure is characterized by the organic combination of punching mode and cavity forming mode. It can not only extrude the complex shape by the die on the press, but also perform multi-directional demould action at one time. Under strong enough pressure, it forces the metal material to pass through the complex flow in the cavity and extrude the complex parts with the shape of the cavity forming die (like injection mold). Therefore, the red punching process is a deeper and wider development of precision forging and hot extrusion technology.

Advantages of red punching process:

(1) Forming is basically not restricted by the external shape of product parts.

(2) It is easy to use common equipment in red punching production and suitable for small and medium-sized enterprises.

(3) High production efficiency, suitable for mass production.

(4) Because the red punching die can use the core pulling device to press hollow forgings, unlike the solid parts from forging die, and the general flash thickness by small red punching die is about 0.5mm, and the flash thickness by forging die is generally more than 2 mm, so the material utilization rate is much higher.

(5) Red punching is a kind of machining technology with little or no cutting. The surface roughness of the forging is close to the die cavity, and the dimension precision can reach 6-7 grade, so its machining allowance is very small.

(6) Great mechanical performance, because the metal blank material is heated, extruded and cooled in red punching process, the metal structure changes, eliminating the defects caused by casting or drawing, making the crystal structure of the parts a line from inside to outside, and improving the mechanical performance of the red punching parts.

(7) After the red punching, the internal grain of the metal is refined, the density of the metal is enhanced, and the corrosion resistance of the part is improved.

(8) Suitable for various nonferrous or black metal processing.

Due to the low investment, high production efficiency, good quality and suitable for mass production, the red punching process has produced good economic results, such as the use of this process to produce a variety of valves, pipe fittings, nuts, etc., with its unparalleled quality advantages, has replaced the past has been used in die casting or casting process.