What are the defects of the final metallurgical parts in the pressing process?

1. The blank density does not meet the planning requirements.
In the production of powder metallurgy parts, the material density is high, and the physical and mechanical properties are also high. In other words, the compaction density, concavity and distribution of P / M parts will determine the function of the product. Therefore, in the process of debugging and constraining the P / M part mold, the density of the blank is the item to be tested.
2. The blank standard does not meet the requirements.
(1) The radial standard is unqualified or the hole spacing is unqualified. There may be problems with mold planning or manufacturing.
(2) The axial standard is unqualified. For the cylinder blank without steps, the axial standard can be adjusted and stabilized by adjusting the powder loading amount, changing the confinement pressure or prolonging the holding time. For the step blank, the step height standard can be changed by adjusting the stamping direction of the combined die, the powder loading rate in each stage and the stamping speed of the floating die.
3. The geometric tolerance is unqualified.
(1) Straight
The causes of non-standard straightness are: uneven die, uneven density distribution of blank, uneven wall thickness of blank.
(2) Parallelism.
The causes of non-standard parallelism are: mold non-standard parallelism, uneven powder loading, etc.
(3) Coaxiality.
The reasons for the non-standard coaxiality are: the precision of the mold is not up to the standard, the precision of the constraint tooling and equipment is low, the mold equipment does not meet the requirements, and the dressing is not uniform.
4. The appearance is unqualified.
High roughness, burr, corner shedding, roughening and crack are common defects of billet.