Scope:

ASTM D7646 shows the relationship between cooling time and temperature. The findings of this test technique can be utilized as a reference for quenchant selection or comparison of quench severities of new and used quenchants.

Procedure:

In ASTM D7646, the cooling time vs. temperature of the silver rod probe assembly is evaluated after heating it to 500 °C in a furnace and then quenching it in an aqueous polymer quenchant solution. To create a cooling temperature versus time curve, the temperature within the probe assembly and the cooling periods are recorded at predetermined time intervals. The ensuing cooling curve is utilized to determine the severity of the quench.

Video 01: Heat treatment precipitation hardening of aluminum alloys

Specimen size:

The specimen used in ASTM D7646 testing should be conditioned at 510 ± 5 °C and soaked at this temperature for at least 2 min.

Data:

In ASTM D7646, the characteristic temperature is measured by the tangential line crossing method based on the cooling curve.

Conclusion:

ASTM D7646 describes the equipment and technique for determining the cooling rate to evaluate the quenching properties of aqueous polymer quenchants.