Thermo-Mechanical Processing and Testing in ASRC
Currently the steel processing group uses two main types of equipment for thermos-mechanical processing.
1. Gleeble - In the AMMC building, there are two Gleeble systems, a HDS V40 and a 3800. Both systems are multipurpose thermos-mechanical testing simulators. At their core, they are capable of heating rates >1000 °C/s and deformation rates up to 2 m/s. This can be achieved in a variety of ways, either tensile, compression (uniaxial or plane) or torsion. This opens up a huge range of possible testing that can be achieved.The machines work by joule heat (direct heating by passing a large current through the sample) and thus the sample need to be electrically conductive and care needs to be taken in specimen design. However, temperature up to 1500 °C can be tested (depending on the material)
A lot of the work that is carried out on these machines looks at simulating the forging/hot rolling process and to obtain metallurgical information about the kinetics of processes such as recrystallisation, recovery, grain growth and homogenisation. Due to the high quenching capability then all these processes can be interrupted at certain intervals to allow a greater insight into the mechanisms of each of these phenomena.
2. Electro-Thermo-Mechanical Tester (ETMT) -
Made by Phoenix Materials testing, this machine is designed as a high throughput mechanical testing machine. Capable of tension, compression, fatigue and bending. This machine operates at temperatures up to 1400°C in a highly controlled atmospheric chamber that is suitable for vacuum (>10-3 mbar), inert (high purity argon) or corrosive (CO2 etc) environments. With a 5kN load cell, this machine is designed for subsize specimens that is fed through our internal high throughput alloy production system. Typical cross-sections are around 3x1mm and the sample length is 50mm (although flexible).
This machine is capable of heating and cooling rates of around 200 °C/s and frequencies of 200 Hz.