Case Depth Measurement

Case hardening or surface hardening refers to the modification of the metal materials' surface that result in forming a thin surface layer called “case” which is substantially harder than the inside section of the component called the “core”. Case depth improves the materials' wear resistance and hardness under dynamic and/or thermal stresses. Case hardening methods include carburizing, nitriding, carbonitriding, cyaniding, ferritic nitrocarburizing, induction- and flame- hardening.

Case depth can be divided into effective case depth and total case depth.

Effective case depth: The perpendicular distance from the surface of a hardened case to the furthest point at which a specified level of hardness is maintained.

Total case depth: The perpendicular distance from the surface of the hardened or unhardened case to a point at which differences in chemical or physical properties of the case and care can't be distinguished.

STEMart provides accurate measurement of the harness and thickness of case depth for the quality control of the hardening process.

Test Methods

• Chemical method: Determine the carbon content (and nitrogen when applicable) at various depths below the surface of a test material, suitable for carburized cases, as well as cyanided or carbonitrided cases.
• Mechanical method: Suitable for all types of hardened case, especially for determination of effective case depth.
  • Cross-section procedure: Suitable for measurement of light, medium and heavier cases.
  • Taper-grind procedure: Suitable for measurement of light and medium cases.
  • Step-grind procedure: Suitable for measurement of medium and heavy cases.
• Visual method
  • Macroscopic visual procedure: Suitable for measuring all types of cases for routine process control.
  • Microscopic visual procedure: Suitable for measurement of carburized cases, carbonitrided cases, nitride cases and flame or induction hardened cases.

For more information about our case depth measurement services, please contact us.