Scope:

The standard test method, ASTM A991, is used to determine the capability of a furnace to fulfill the permitted temperature variation specified in the applicable product specification. The uniformity survey aims to select the temperature range present in different furnace parts under normal operating conditions. Those who utilize, manufacture, and provide calibration services to heat-treat furnaces used in processing steel products can employ the techniques in this test method.

Test Procedure:

In ASTM A991, test conditions and test frequency should be according to requirements:

1. Time and temperature in the furnace are monitored, then test sensors are conveyed through the furnace.
2. Statistical samples are taken by using alternative surveying techniques described in ASTM A991.
3. Observations are taken at intervals of five minutes or fewer for at least 30 minutes after thermal equilibrium is attained if no recurrent temperature profile is detected.

Specimen Size : 

Steel items must be heat treated as required in the working zone.

Data:

In ASTM A991 testing, if there isn’t a repeated temperature profile, then that means thermal equilibrium is not reached.

Conclusion:

The standard test method, ASTM A991, is used to determine the capability of a furnace to fulfill the permitted temperature variation specified in the applicable product specification.