The main problems in the current thick plate stamping are:
(L) rough surfaces of punching parts, even uneven steps. The dimension and shape accuracy of the blanking parts are low, and the blanking material has obvious arch deflection. The quality of blanking parts is low, which seriously affects the popularization and application of the technology. How to improve the quality of thick plate stamping is a key issue to be discussed urgently.
(2) die life is low, especially for hard steel or thick plate, and die life is lower. Therefore, it hinders the popularization of the process.
(3) there are still some difficult problems to be explored in the process, such as pre processing and preparation of raw materials, including leveling, blanking and spheroidizing annealing, cleaning, lubrication, and the preparation of strips, pieces, and blocks. It is difficult for the general factory to be restricted by the equipment conditions and the immature technology.
(4) the determination of stamping process and the design and manufacture of the die structure, including material selection and heat treatment of the working parts of the stamping die, are still to be explored.
(5) the theory of thick plate stamping process has not yet been put on the agenda. Such as: improving the quality of the plate blanking, reducing the effective measures for the punching pressure of the thick plate, reducing the stamping noise of the thick plate, and popularizing the hot and clean blanking technology of the thick plate, etc. all need to be studied in order to guide the practice of the factory.
It should be pointed out that thick plate stamping is a modern stamping technology with great potential, excellent efficiency and broad prospect. Its development and popularization depend on the development and progress of material technology, mold technology and production technology of stamping equipment and related basic technology. Therefore, the development and application of thick plate stamping technology, in fact, is a system engineering involving many basic technological fields, and is a key research topic for a long and arduous modern stamping technology.
Because the cold shear strength of cold punched thick steel plate is large, when the material thickness t reaches 4 20mm, the P~ value increases with the increase of T value. The convex and concave dies made of conventional cold stamping die materials are difficult to withstand the excessive compressive stress during blanking. Sometimes P, the two value will exceed the tonnage of the field equipment and can not be cold stamping. The use of hot stamping steel plate can reduce the blanking force. After the heating of steel plate, the a two value of the shear strength decreased significantly, and the Pmax value decreased significantly, which provided superior conditions for thick plate stamping. However, heating steel plates need some heating equipment, and the use of mechanical presses to heat blanking is not appropriate. Due to the strict control of heating temperature, it is necessary to clean up the rust and oxide skin on the surface of the hot plate. The hot flushing equipment should also be suitable for the discharge and discharge of hot stamping parts and the discharge and stacking of hot waste. Therefore, according to practical experience, it is recommended to use friction press to make thick steel plate hot stamping.