Class 8 includes case-hardened, through-hardened, and tool steels—ferrous materials commonly used in structural, mechanical, and tooling applications. Their microstructures are influenced by alloying and thermal processing, resulting in enhanced hardness, wear resistance, and toughness. Tool steels often contain elements like vanadium and molybdenum and may reach Rockwell C hardness levels above 60.
Ensure specimen edges remain intact and sharp, especially when analyzing case depth or coating transitions.
Hard carbides in tool steels may dislodge during polishing, leaving voids or relief.
Excess etching can obscure grain boundaries or martensitic structures in hardened zones.
Martensite, retained austenite, and carbides may require multiple etchants to differentiate clearly.
Use abrasive or diamond saws with coolant. Clamp firmly to avoid edge chipping or deformation.
Compression mounting is suitable. For edge-sensitive applications, use edge retention mounting media.
Use SiC or alumina with decreasing grit sizes. Maintain moderate pressure and clean thoroughly between steps.
Diamond polishing followed by colloidal silica to reveal martensite and avoid relief in high-carbide regions.
Martensite and carbides clearly resolved
Edge features retained and sharp
Minimal relief in hardened zones
No carbide pull-out or etching artifacts