The high-temperature pseudo-invar effect in multilayer steel materials

Abstract

The paper presents the results of research into Coefficients of Thermal Expansion (CTE) in multilayer steel material produced by hot pack rolling. It has been discovered that the material comprised of interleaving layers of steel features abnormally low CTE values in the direction normal to the rolling plane. A hypothesis has been proposed to explain the phenomenon by an interrelation between normal and tangent stresses generated in the interlayer boundaries within the material. A leading role of reactive stresses is confirmed by the results of the metallographic analysis. It has been shown that cyclic heating at a high temperature provokes recrystallization on the interlayer boundaries due to the difference between the CTE values of the adjacent layers and the high-temperature impact.