Why do stamped and machined bent parts crack?

In the process of stamping processing, the crack problem of bent parts has been one of the difficult problems. In this paper, we will discuss the causes of cracking of bent parts in stamping processing from the aspects of material properties, process parameters and mould design, and put forward corresponding measures to solve the problem.

1. First of all, we should understand the material properties of the bent parts.

Different metal materials have different mechanical properties, such as modulus of elasticity, yield strength, breaking strength and so on. These properties determine the deformation ability and damage resistance of the material when subjected to force. Therefore, when selecting the material of the bending part, its mechanical properties should be fully considered, and the use of high-strength steel should be avoided.

2. The selection of process parameters has a great influence on the crack generation of bending parts.

In the stamping process, bending force, bending radius, bending speed, etc. are process parameters that affect crack generation. Therefore, in the stamping process, appropriate process parameters should be selected according to the mechanical properties of the material and the actual demand, in order to reduce the risk of crack generation.

3. The design of the mould also has a great influence on the crack generation of bent parts.

The mould is a tool that is in direct contact with the material during the stamping process, and its shape, size and surface quality will affect the quality of the bent part. When the mould design is unreasonable, it may lead to stress concentration in the material during the bending process, thus generating cracks.

In view of the above analysed reasons for cracks in stamping processed bent parts, several solution measures can be adopted:

1. Select reasonable materials. According to the use of bending parts of the environment and requirements, choose appropriate metal materials, avoid the use of high-strength steel. At the same time, heat treatment, cold treatment and other methods can be used to improve the mechanical properties of the material, to improve its crack resistance in the stamping process.

2. Optimise process parameters. In the stamping process, appropriate process parameters should be selected according to the mechanical properties of the material and the actual demand, such as bending force, bending radius, bending speed, etc.

3. improve mould design. When designing the mould, the characteristics of the material and process requirements should be fully considered, and the shape and size of the mould should be set reasonably. Rounded corners, reinforcement and other structures can be used to disperse the stress and avoid cracks caused by stress concentration. At the same time, the surface quality and lubrication conditions of the mould should be ensured to reduce the influence of friction resistance on crack generation.