Defects in Metal Material Forming Processing, Part 4

Defects in metal forming processes can arise due to various factors, including material properties, process parameters, and environmental conditions. Here are some common defects associated with metal forming:

Foreign Matter Intrusion

The surface of metal or non-metallic intrusion products is called foreign matter intrusion.

The metal intrusion has a clear interface with the substrate, a clear outline, different metallic luster, and is in the form of dots and blocks.

After peeling, pits are formed; non-metallic intrusions have different shapes and colors, are mostly brittle, have no metallic luster, and are distributed in the form of dots, flakes, and long strips along the processing direction, and are not easy to peel off.

Sources of foreign matter: Oxide scales and lubricants formed by heating adhere to the surface of tools and products; fragments and adhesions of tools and molds; metal chips, burrs and flash of cracked edges; furnace chips and oil stains of heat treatment furnaces; debris in the emulsion; foreign matter on the rolling track and guide plate.