Microindentation hardness testing, commonly called "microhardness" testing, is an important procedure for quality control of surface hardened components. However, the technique is very labor intensive and fatiguing for the operator. Furthermore, studies conducted by ASTM Committee E-4 on Metallography have demonstrated that the operator's perception of the location of the indent tips is the major source of variability in such tests. Due to the nature of the equations to calculate Vickers or Knoop hardness, the variation in hardness due to indent measurement errors increases as the indent becomes smaller. Consequently, high hardness specimens are more sensitive to this problem than soft metals. To reduce the operator influence on test reproducibility, precision and bias, and to reduce labor costs, microindentation hardness testers have been coupled to automated stages and computer-aided image analyzers.
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