ASTM E1225 Thermal Conductivity of Solids Using the Guarded – Comparative-Longitudinal Heat Flow Technique

Scope:

ASTM E1225 test method covers the characteristics of engineering materials like ceramics, polymers, metals and alloys, refractories, carbons, and graphites. It determines their applications and specifications. The method proceeds with the quality check, determination of thermal conductivity, and the testing of the chemical composition of materials.  The results obtained from this method help in quality control, research, and performance evaluation of solids.

Procedure:

In ASTM E1225, the thermal properties of the specimen are determined and the specimen is placed in a test stack of known temperature. The specimen is placed between two meter bars and the contact between the specimens is ensured by applying adequate force. The readings of thermal conductivity are taken at equilibrium. The output of all temperature sensors is measured once the system has reached a steady state. 

Specimen detail:

Specimen size should be as per the requirements. In this ASTM E1225 test, the specimen radius, rA, must be such that rB/rA is between 2.0 and 3.5.

Result:

The outputs from the temperature sensors shall be converted to temperature, and the apparent heat flow per unit area, q’, in the meter bars shall be calculated using the formula.

Conclusion:

The ASTM E1225-13 test method is specifically important for the quality assurance and durability check of solids. Their role in various industrial services is determined.