Showing 3 results for Thermal Shock
Chandler H.w.,
Volume 2, Issue 2 (6-2005)
Abstract
Being brittle and having low thermal conductivity, refractories suffer damage and sometimes fail in service as a result of thermal shock. While the approach of those making fine-grained technical ceramics is to make their products sufficiently strong to withstand thermal stresses the refractory technologist is more cunning. He uses, often little known, devices to provide resistance to thermal shock that minimise but do not eliminate damage to the component. In this paper the basic equations of thermal conduction and elasticity are presented and followed by some immediate results that should guide the designer of components subject to severe thermal environments. The influence of size and shape of the refractory components is then discussed along with ways in which refractory producers can engineer the thermal and mechanical properties. In particular, the methods used to tailor fracture behavior to optimize the thermal shock resistance are treated in some detail.
M. Adjabshiri, S. Sharafi,
Volume 4, Issue 1 (6-2007)
Abstract
Abstract: Strength at elevated temperatures and thermal shock resistance of austempered ductile
irons at high temperatures has been less intentioned, because of instability of ausferrite phase. In
this research the tensile properties of this iron and pearlitic ductile cast iron have been
investigated by short time high temperature tensile tests. Also thermal shock tests were done at
the molten lead bath at 1000 C . In these experiments, at first samples were immersed partially in
the molten lead bath for 25 seconds and then either cooled in air or quenched in water. Results of
short time high temperature tensile and thermal shock tests showed that ADI samples have higher
strength and shock resistance than the pearlitic ductile samples.
M. Ghassemi Kakroudi,
Volume 5, Issue 4 (12-2008)
Abstract
Abstract: Refractory materials containing cordierite (2MgO.2Al2O3.5SiO2) and mullite (3Al2O3.2SiO2) are used as
support in furnaces, because of their low thermal expansion properties which confer them a very good ability to
thermal shock resistance. Composed of two phases presenting very different CTE (1.5–3×10-6 for cordierite and
4–6×10-6 K-1 for mullite), these materials can develop damage during thermal cycling due to internal stresses.
The resulting network of microcracks is well known to improved thermal shock resistance of materials, since it usually
involves a significant decrease in their elastic properties. This paper is devoted to the characterisation of the damage
generated by this CTE mismatch, thanks to the application of a specific ultrasonic device at high temperature.
