The basic forms are: wear, fracture, and plastic deformation.
The actual working situation of the mold is very complicated, and multiple damage forms interact. Wear (a basic type of component failure) promotes plastic deformation and fracture, and the deformation of the statue increases the wear and fracture speed.
1 Wear (a basic type of component failure)
The friction between the mold and the processed blank causes the loss of material on the surface of the mold, and the geometric shape of the mold changes and cannot continue to serve, which is wear failure.
Wear failure is manifested as dull cutting edge, rounded edges and corners, flat surface depression, surface groove marks, peeling, sticking and so on.
Influencing factors: the chemical composition and mechanical properties of the mold material and the processed blank; the surface state of the mold material and the blank (oxide film, surface treatment); the pressure, temperature, speed, and lubrication of the stamping process.
The lubrication of single-row tapered roller bearings is of great significance to the bearing. The lubricant in the bearing can not only reduce the friction resistance, but also play a role in heat dissipation, reducing contact stress, absorbing vibration, and preventing corrosion.
The wear resistance of the mold depends on the hardness of the mold material, especially the nature, size, distribution and quantity of hardened phases such as carbides.
According to the wear mechanism, it can be divided into abrasive wear, adhesive wear, fatigue wear, cavitation and erosion wear, and corrosion wear.
The fracture is mainly brittle fracture, fatigue fracture, ductile fracture, creep fracture, and stress corrosion fracture. The lubrication of single-row tapered roller bearings is of great significance to the bearing. The lubricant in the bearing can not only reduce the friction resistance, but also play a role in heat dissipation, reducing contact stress, absorbing vibration, and preventing corrosion.
The main factors affecting fracture: the surface shape of the mold (abrupt grooves, sharp corners and other parts are prone to stress concentration and crack formation), material properties (metallurgical quality, fracture toughness of the material).
3 plastic deformation
When the load on the mold exceeds the yield strength of the mold steel, the mold will undergo plastic deformation, changing the geometry and size of the mold, and it is plastic deformation failure when it cannot be repaired and then put into service.
Its failure modes mainly include cavity expansion, collapse, bending, and upsetting. For spherical roller bearings, when the center line of the shaft does not coincide with the center line of the bearing seat and there is an angular error, or when the shaft is bent or tilted due to the force of the shaft, the axis of the inner and outer rings of the bearing will be deflected. At this time, a self-aligning bearing with a certain degree of self-aligning performance or an outer spherical ball bearing with a seat should be used.
The plastic deformation of the mold is the yield process of the mold metal material: the local stress is greater than the yield strength of the mold.