Determination of Alloy Capability to Thermal Shock Resistance
C Paul Qiao, Daniel Csaki, Dakota Dorner
ABSTRACT
An undulation thermal exposure is a common operational condition for many high temperature engineering equipment and structures. A safety factor of application temperature (maximum temperature) has been conventionally adopted during the related engineering application design such as valvetrain components. Depending upon application, different materials properties such as high temperature compressive yield strength, ultimate tensile strength, stress rupture strength and creep strength have been used to define the materials thermal shock resistance. The complexity of thermal exposure environment often requires an alloy to have a stable metallurgical property such as microstructural stability and sustained hardness.
For valvetrain engineering application, changing in component hardness under an elevated temperature service condition can reduce intended performance related to wear resistance and erosion resistance. A heat and wear resistance alloy J130 widely used for valve train component application has been adopted for carrying out this thermal shock resistance study exhibiting that the alloy high temperature capability can be precisely defined for the intended high temperature application as a design parameter to engine performance.
Thermal aging behavior of alloy J130 was investigated utilizing high precision laboratory heat treatment furnace with a variety of thermal socking temperatures and durations. Bulk hardness, microhardness measurement and microstructural characterization have been applied to reveal the material behavior under different thermal exposure conditions and relationship between microstructure and mechanical properties.