Scope:

ASTM A1038 test method determines comparative hardness values by applying the Ultrasonic Contact Impedance Method (UCI Method) on metallic samples. The UCI hardness test can be used to take hardness measurements on positions difficult to access, such as tooth flanks or roots of gears. The ASTM A1038 hardness test is a superficial determination that is done only for measuring the hardness condition of the surface contacted.

Test Procedure:

To perform ASTM A1038 hardness test, the probe is connected to the indicating unit and the
instrument is turned on. The probe is held firmly with its axis in a perpendicular position relative to the test piece surface. Steady pressure is exerted against the test piece during the loading phase. Vertical probe position is to be maintained as long as the load is effective. Then, the instruments indicate the end of the measurement by an acoustic signal and display the value of hardness.

 Specimen size:

The specimen used for ASTM A1038 hardness test, generally consists of a probe containing a rod with a defined indenter.

Data:

In ASTM A1038 testing, hardness is reported in SI units and is considered as standard.

The error E in the performance of UCI hardness testing relative to a standardized reference
value is calculated as :

E = | 100 × ( x’ – x_ref. / x_ref. ) |

Where,

x’ = the average of the measurements made on a standard reference block.

x_ref = the certified reference hardness reported for the standard reference block.

Conclusion:

ASTM A1038 test method covers the determination of comparative hardness values of metallic elements by applying the Ultrasonic Contact Impedance Method (UCI Method).