Causes and Solutions of Common Defects (Cracks, Oxidation) in Forging Processing

Causes and Solutions of Common Defects (Cracks, Oxidation) in Forging Processing

During the forging processing, cracks and oxidation are the most common quality defects. They not only affect the mechanical properties and service life of forgings, but may also lead to product rejection and increase production costs. Clarifying the causes of these two types of defects and adopting targeted solutions are the key to improving forging quality and reducing loss. Combining with actual production conditions, the detailed analysis of their causes and solutions is as follows.

Cracks are the most fatal defects in forging processing, mainly caused by three factors: first, improper heating process. Excessively high heating temperature or too fast heating rate leads to stress concentration inside the metal, and cracks are prone to occur after cooling; second, unreasonable forging process. Insufficient forging force, uneven rhythm, or excessive metal deformation during forging exceed the plastic limit of the material; third, impurities and air holes in raw materials. Cracks are prone to occur at the weak parts during processing.

Oxidation defects are mainly manifested as oxide scale and uneven color on the forging surface. The main cause is the oxidation reaction between metal and air during heating. Especially at high temperature, the oxidation speed accelerates. If effective protective measures are not taken, the oxide layer will continue to thicken, affecting the forging accuracy and surface quality.

Corresponding solutions can be taken for the two types of defects: for crack defects, optimize the heating process, control the heating temperature and heating rate, select qualified raw materials, and reasonably adjust the forging force and rhythm to avoid excessive deformation; for oxidation defects, adopt protective measures during heating, such as introducing protective gas, applying anti-oxidation coating, shortening the heating time to reduce the contact between metal and air, and clean up the oxide scale in time after processing. Good process control can effectively reduce the defect rate and ensure the stable quality of forgings.