A New Technology to Extend the Service Life of Dry Powder Pressing Mold
The mature powder metallurgy process is widely used in machinery and other industries. The quality and life of the powder is the important factor to determine the quality and life of the powder metallurgy parts. Therefore, it is very important to improve the quality and life of the mold. The use of cryogenic treatment can improve the wear resistance of steel in order to achieve the quality and life of the mold, parts quality and life will be increased.
Dry Powder Pressing Mold is usually caused by wear and tear caused by parts of the size of the deviation. Tool steel in the heat treatment in the metallographic phase will usually leave a lot of austenite, the use of molds prone to organizational changes, resulting in tissue stress, resulting in early damage from the mold, especially when the residual austenite over 5% Reduce the strength and abrasion resistance of the material.
In the powder metallurgy industry widely used Gr15 steel as a mold material, but in use with Gr15 steel mold quality and life are low, so the use of cryogenic treatment to improve the wear resistance of steel, and ultimately improve the Dry Powder Pressing Mold The quality and longevity.
After a series of experiments, Gr15 steel in the normal heat treatment still remains more austenite, cryogenic treatment is the best way to reduce the austenite residue. When the temperature of the cryogenic treatment is reduced to -140 ° C or lower, the amount of retained austenite is substantially stable.
After the cryogenic treatment, the toughness of the GR15 steel is not changed, but the strength is slightly increased. This is because the cryogenic treatment changes the austenite to the martensite, the organization is more refined and the hardness is enhanced. Therefore, the overall strength of the GR15 steel Improved, and thus the quality of the Dry Powder Pressing Mold was significantly improved.
Experiments show that the Dry Powder Pressing Mold reduces the amount of austenite after cryogenic treatment, increases the toughness and strength, thus significantly improves the quality and life of the mold, and the economy of the mold is further improved. Cryogenic treatment is a method worth promoting and using, on the basis of which we have to continue to study the effect of a better way to make Dry Powder Pressing Mold quality and life again.
Under normal circumstances, the dry powder cutting mold brittle cutting effect, in fact, much better than plastic, and can more easily meet the relevant processing requirements, but for the same material, in the metallographic structure, if it is smaller Of the words, then the better, this point in the industry are more recognized.
First, Dry Powder Pressing Mold In the forging equipment, if it is based on the weight of the forging classification, then it is best to use tonnage larger mold or equipment, and in forging before the use of hammer or hammer drill on the mold Preheating in advance to ensure the good operation of the production process.
Second, the Dry Powder Pressing Mold in the preparation of the blank powder, blank in the cutting time, it is best to carry out cold saw, and according to the different requirements of Dry Powder Pressing Mold, in the choice of raw materials, should be in accordance with the level to choose, different Of the material selection of different molds, so that the processing will be more accurate.
Third, the dry powder to suppress the mold blank heating, the blank when the heating, it is best to slow to prevent the rapid heating of the way to avoid the phenomenon of burning, and in the heating process, the temperature should not limit the lower limit, If there is a burning situation, you should first cool it and then press it.
If you are heating a number of Dry Powder Pressing Molds, between each piece and each piece must be provided with a certain clearance during heating, and during the whole heating process, the parts must be flipped at all times to ensure that they are There will be no bonding between, to ensure that the product processing and use of normal.
After the cutting of the Dry Powder Pressing Mold in the contours and shape is still relatively poor degree of roughness, and pure structure and made from the contours of a large difference, mainly because of the cutting process, the plastic appeared serious Deformation, and we in the cutting time, the choice of the tool is also more important.
Because the different tools in the precision, as well as fine cutting high and low speed will have an impact, it is serious will affect the normal use of Dry Powder Pressing Mold. If it is for the brittle Dry Powder Pressing Mold material processing, then the rate of cutting for the roughness of the impact is not large.