Mill Scale
Mill scale refers to oxide layers on metal surfaces that are formed by thermal effects during cutting, heating, or forming processes.
The oxide layer affects subsequent processing and coating processes.
Formation of tinder
Scale forms when metal surfaces react with oxygen at high temperatures. This process creates oxide layers of varying thickness and adhesion on the surface or cut edges of sheet metal components.
Factors influencing mill scale formation
- temperature load
- oxygen input
- material composition
- separation process
- process duration
Impact on subsequent processes
Residual mill scale affects surface quality and can hinder stable downstream processes. In particular, coating, welding, and bonding processes are sensitive to oxide residues on the component surface.
Typical effects
- reduced coating adhesion
- unequal surface conditions
- unstable subsequent processes
- increased post-processing effort
- impairment of surface appearance
Mill scale in the context of oxide removal
In the oxide removal process step, oxide layers are mechanically removed to produce clean metallic surfaces and reproducible initial conditions for subsequent processes.
Difference between mill scale and slag
Slag describes molten and subsequently solidified material deposits on the cutting edge. Mill scale, on the other hand, forms as an oxide reaction layer on the surface of the material.
Technical differences
- Slag: molten and solidified material
- Mill scale: oxide surface layer
- Slag: predominantly at cut edges
- Mill scale: flat on metal surfaces
FAQ
Why does mill scale need to be removed?
Residual mill scale can impair coating adhesion and lead to unstable downstream processes.
In which processes does mill scale form?
Scale is primarily formed during thermal machining processes involving high temperature stress and contact with oxygen.