Springback is not only related to fillet, but also related to material mechanical properties, bending angle, bending radius and thickness. Generally speaking, the yield strength and bending angle of materials are directly proportional to the bending deformation coefficient r/t, and the bending rebound angle is inversely proportional to the elastic modulus of materials.
It has a certain relationship with stamping speed, part shape and technology. It is difficult to quantify by formula, and experience and mold modification are very important.
Extended data:
High-strength steel and ultra-high-strength steel have realized the lightweight of vehicles and improved the collision strength and safety performance of vehicles, so they have become an important development direction of automotive steel. However, with the improvement of plate strength, the traditional cold stamping process is easy to crack in the forming process, which can not meet the processing requirements of high-strength steel plate.
In the case that the forming conditions cannot be met, the hot stamping technology of ultra-high strength steel plate is gradually studied internationally. This technology is a new technology integrating shape, heat transfer and microstructure transformation. It is mainly a forming process by using the characteristics of increasing plasticity and decreasing yield strength of metal plates in high temperature austenite state.
However, hot forming needs in-depth research on process conditions, metal phase transformation and CAE analysis technology, which is monopolized by foreign manufacturers and developed slowly in China.
In the past, when producing deep drawing or heavy stamping workpieces, everyone thought that ep lubricating oil was the best choice to protect the mold. It has a long history to mix sulfur and chlorine extreme pressure additives into pure oil to improve the service life of dies. However, with the appearance of new metal-high strength steel and strict environmental protection requirements, the value of EP oil-based lubricating oil has been reduced and even lost the market.
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