What is the reason for the cracking of stamping parts?
- Reasons for bending and cracking of stamping parts
1. The steel used has poor plasticity, including the low elongation of the steel, the uneven grain size, the continuous occurrence of harmful Widmanstler structures, the cold bending performance that does not meet the technical standards, and the poor surface quality of various kinds, etc. Problems may cause a drop in plasticity, resulting in the consequences of bending cracking.
- When the angle between the bending line and the direction of the embossing of the sheet does not meet the layout regulations, the angle between the direction of the embossing of the bent sheet does not meet the process regulations.
3. The bending radius is too small, and the deformation degree of the outer metal during the bending process exceeds the deformation limit.
4. The quality of blank shearing and punching sections is poor, such as large burrs or cracks in the sheet at the bend.
5. The thickness of the material is seriously out of tolerance, which will cause difficulty in feeding and cracking.
6. Factors such as the wear of the mold fillet radius or the too small gap, the rough surface of the die or the improper design structure cause the feeding resistance to be large, and the stamping parts are easy to crack.
7. The quality of pickling is poor, and the pickling process of steel is carried out carelessly, resulting in over-pickling or hydrogen embrittlement, resulting in reduced plasticity and cracking.
8. Insufficient lubrication, high friction, easy to cause cracks.
Second, the solution to the bending and cracking of stamping parts
1. Improve the condition of the steel plate, mainly including the selection of steel with good plasticity (such as good cold bending performance), local annealing in the parts with large deformation, and improving the quality of the sheared blank section.
2. Improve the technical state of the working part of the mold, reduce the roughness of the working surface of the convex and concave mold, and adjust the reasonable gap.
3. Formulate the correct process plan, select the appropriate process plan, so that the flow resistance of the steel during the bending process is small and the deformation is easy.
4. Improve the manufacturability of the product structure, select a reasonable fillet radius, and increase the process incision at the local bending part to avoid root fracture.
5. Improve lubricating conditions, lubricate rationally, and use lubricating oil with good lubricating performance to reduce the resistance of steel flowing during the bending process.