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SGS MSi can perform the following

Case Depth Examination

Case depth examination is typically required to verify each carburizing or carbonitriding heat treat batch or lot. A gaseous atmosphere is generated within the furnace which diffuses into the component by the laws of equilibrium. The amount of time and the carbon potential of the atmosphere dictate the resulting total case depth and effective case hardness.

Case Depth Test Method & Specification

The following is the specification that is in accordance with our A2LA and ISO accreditation.

  • SAE J423

To test for the total case depth, the following is to be performed

  1. Section & prepare the sample for metallographic examination
  2. Etch the prepared metallographic specimen with a 3% Nital etchant to reveal the microstructure
  3. Measure the total case depth as the depth below the surface where no change in microstructure can be observed resulting from heat treatment diffusion. A NIST traceable filar scale should be used for the measurement.
  4. Verify the depth measurement in at least three separate locations. Report the range observed. Do not average the values.
  5. Examine the case microstructure for any detrimental microstructural conditions and, if detected, notify the client.
  • As-Received Grains
  • Oxidation Procedure
  • Carburation Procedure

In an “as-received grain size examination”, we prepare metallographic specimens from the sample without any additional treatment. For example, an as-received grain size examination can be performed for stainless steels or carbon/alloy steels that haven’t been quenched.

In a “McQuaid-Ehn (carburizing) grain size” examination, we prepare carbon/alloy steel metallographic specimens from the sample by surrounding the specimens with a carburizing compound, heat treating them, and slowly furnace cooling them. This method is utilized mainly for quenched and tempered carbon/alloy steels with low carbon content.

In an “as-received grain size examination”, we prepare metallographic specimens from the sample without any additional treatment. For example, an as-received grain size examination can be performed for stainless steels or carbon/alloy steels that haven’t been quenched.

Our Metallurgical Lab is ASLA Accredited Our Full Service Metal Testing Laboratory Is Nadcap Accredited