Various devices have been developed for application of SS DTA in situ during actual materials thermal and thermo-mechanical processing and in simulated processing conditions.
As-Welded Setup
The figure below presents a setup for performing in situ SS DTA during fusion welding. The heat affected zone (HAZ) and weld metal thermal histories are measured by embedded thermocouples and by thermocouple plunge in the weld pool, respectively. The thermocouple signal is recorded by a fast sampling data acquisition system and personal computer. The acquired thermal histories are then processed by the SS DTA software to determine the phase transformation temperatures. A similar setup has been applied to study the phase transformations in the HAZ, the thermo-mechanically affected zone, and the stir zone in friction stir welds.
Light Radiation Furnace Setup
The setup shown in the figure below has been developed for in situ application of SS DTA during the heating and cooling cycles of various heat treatment processes and during the post weld heat treatment. This setup uses a furnace with controlled constant rate heating and cooling (temperature control), free furnace/air cooling. It has also been applied for the determination of the A1 and A3 temperatures in steels by the ASTM A1033-04 procedure.
Gas Chamber Melting Setup
The SS DTA device shown in the figure below has been developed for the determination of solid–liquid and solid-state transformations during rapid heating and cooling. In this device, a small sample of the tested alloy is heated and cooled in the shielded atmosphere over a water-cooled copper mold by a concentrated energy source as gas-tungsten arc. Heating and cooling rates between 6 and 1000C/s have been achieved in this device by controlling the power source energy, the sample mass, and the shielding gas flow rate and thermal capacity.
Alexandrov, Boian T., Dr., and John C. Lippold, Dr,. “In Situ Determination of Phase Transformations and Structural Changes During Material Processing.” In-Situ Studies with Photons, Neutrons and Electrons Scattering. Berlin, Heidelberg: Springer-Verlag, 2010. 113-31. Print.