What is Hot Punching Process?
The hot punching process is an advanced hot metal press processing technology which develops on the basis of precision forging and hot extrusion in order to improve the mechanical properties of the parts by changing the processing method. The hot punching process is heating the metal blanks like precision forging, and then forming them in the mold. Except for large hot stamping, it is usually once-forming, and precision forging generally needs several times of pressure forming.
The hot punching process has extensive and far-reaching practical significance for mechanical manufacturing, daily hardware products, national defense, aerospace parts and other applications. For example, diesel engines, tractors, automobiles, missiles, etc. Have many mechanical parts that are very suitable for hot punching process. At present, the hot punching process has been widely used in daily hardware industry such as various valves, pipe fittings, nuts, etc of pipe hardware, which is punched by copper. They own matchless quality and have replaced pressure casting and casting products in the past.
T Pipe Fitting Hot Punching Die
Irregular Fittings Hot Punching Tool Dies
The compare between hot punching process and hot extrusion process
The molds of hot extrusion and cold extrusion processes are basically the same, the flow of the metal material in the cavity is relatively simple.The shape of the formed part is simple and mostly similar to that of the cold extrusion part.
The structure of hot punching die is more complicated than the hot one, the structural feature is that the punching method is combined organically with the forming method of the cavity die. It can not only extrude the cavity extrusion die on the press, but also implement multiple orientations at one time. Under sufficient pressure, it forces the metal material to flow through the complex die cavity and is extruded to complex parts of shape of the cavity mold (injection mold).
Therefore the hot punching process is a deeper and broader development of precision forging and hot extrusion process.
The features of hot punching process
- Hot punching process is a process of forming metal material by hot stamping, belonging to the field of thermal processing. Firstly, put the heated metal blank into mold, and then the stamping action caused by press makes plastic deformation occur in it, thereby pressed part with various shapes and good mechanical properties can be made.
- The metal billet is deformed by heating and extrusion, which eliminates defects of original material caused by casting and drawing. The deformed metal fiber structure is distributed from inside to outside in a continuous state, which improves the mechanical properties of hot punched part.
- After the metal material heated and extruded, internal crystal grains are refined, the density of the metal is enhanced, and the surface corrosion resistance is improved.
- The hot punching process can extrude piece of any shape especially advantageous for the small rod forging, deep hole cup forging, inner and outer diameter upper teeth, the toothed shape, the upper cup lower rod forging and the forging of small middle and four large faces. The deformed metal is in a three-direction stress state due to the extrusion, so it’s easy to process the difficult-to-deformed precious metal.
- During the extrusion, the metal blank is put into the die and material storage cavity firstly, and then the blank metal is squeezed into the die cavity to form under the pressure of upper die. This forming method seems to be similar to injection mold, but the flow of the extruded metal is not liquid, so its flow performance is worse than that of injection mold.Compahot with the forging die, the metal deformation rate of the hot stamping die is higher, and fiber continuous structure of the metal shape of hot stamping die is much better than that of injection die and forging die.
- The hot punching process has good adaptability and can be widely used. Actually the hot punching process is similar to precision forging, but the requirements to the die and press are much simpler than precision forging. As long as little correction to the mold or machine, the extrusion can be realized on general pressure machine.
- Hot punching process is one of the processing methods of metal parts without cutting, which can save a lot of metal raw materials.It not only has high production efficiency, but also saves labor and materials. It can improve economic efficiency and product quality obviously.
Advantages of hot punching process
- Forming is not limited by the external shape of product parts;
- Common equipment is used in production, which is easy to put into production and suitable for small and medium-sized enterprises;
- High productivity, suitable for mass production;
- As a result of use of core-pulling device, the interior of part pressed out is hollow, unlike the solid interior of forging die processed out, and generally the rough edge thickness of small hot stamping die is about 0.5mm, and forging die part is generally more than 2mm, so the material utilization rate of hot punching process is higher.
- hot punching press is a process with less cutting, the roughness of surface is close to mold, and size accuracy can reach 6-7 level, so its amount of mechanical cutting is very small;
- The mechanical properties of the hot punching process are good, because after it the metal blanks are heated, squeezed and cooled, the metal structure changes, eliminating the defects caused by casting or drawing. The internal crystal structure is linear from inside to outside, which improves the mechanical properties of the piece.
- After hot punching process, the internal grain of the metal is refined, which enhances the density and improves anti-corrosion ability of parts;
- Suitable for all kinds of non-ferrous or black metal processing.
copper hot forging mold
Valve Hot Punching Die
