ASTM E384 Knoop Microhardness


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APM Testing provides A2LA accredited services for Knoop micro-hardness testing at a fair price, with prompt delivery, and a detailed test report. Our laboratory also provides laboratory services for plastic testing, metal testing, rubber testing, oil testing, paint testing, plating testing, adhesive testing, circuit board testing, and other testing.

Purpose: Measure the micro-hardness of a metal sample per ASTM E384.

Sample: One sample 0.010 inches (0.25 mm) square or larger.

Basic Description: ASTM E384 is a method of measuring micro-hardness by pushing a pyramid shaped diamond indenter into a metal and then measuring the size of the indent using a microscope. Usually the sample is cross sectioned, mounted (ASTM E3) in epoxy, and polished to a mirror finish before testing. This method covers Knoop micro-hardness using an elongated pyramid indenter and Vickers micro-hardness using a square (equilateral) pyramid indenter. The indenter is pushed into the sample using a fixed load which is usually 500 grams but loads ranging from 10 to 1000 grams may be used. Large and non-uniform samples can be better measured using ASTM E18 Rockwell Hardness or ASTM E10 Brinell Hardness. Knoop micro-hardness is used to measure the hardness of areas as small as 0.0015 inches in size (0.05 mm). Hardness profiles from the surface to the core of a sample allow measurement of effective case depth or depth of decarburization. High surface hardness will give good wear resistance but a softer core is normally required to preserve ductility (impact strength). Results are reported in a table with up to ten indents per sample.

Limitations: The sample must be polished to a mirror finish and is usually cross sectioned and mounted (ASTM E3) in epoxy prior to testing. Non-uniform materials often give inconsistent results. Samples less than 0.0015 inches (0.05 mm) thick are usually too thin for accurate measurements.


  • Mitutoyo MVK-H1 Microhardness Tester

Method Publisher:


  • Knoop Micro-Hardness
  • Knoop Hardness
  • Vickers Micro-Hardness
  • Vickers Hardness
  • Case Depth
  • Micro-Indentation Testing
  • Hardness Testing

Related Techniques: