Effect of Trace Rare Earth on Mechanical Properties of Corten Steel Coil

For rare earth corten steel coil with oxygen content of 0.004%~0.007% and sulfur content of 0.008%, the content of rare earth is in the range of 0.005%~0.025%, and the content of solid solution rare earth is 5x10-6-16x10-6. The banded MnS inclusions in corten steel coil are gradually modified to spherical dispersed rare earth inclusions with size less than 2 microns by appropriate rare earth elements. The structure of corten steel coil is refined, and there are some solid soluble rare earth elements in corten steel coil, which improves the comprehensive mechanical properties of corten steel coil. After adding rare earth, the tensile strength and elongation of corten steel coil are increased, and the yield strength ratio is reduced. When the RE content in corten steel coil is less than 0.012%, the comprehensive mechanical properties of corten steel coil are improved obviously with the increase of RE content and RE solid solution content.

After adding rare earth into CuP corten steel coil, the impact toughness of corten steel coil is improved, especially at low temperature, within a certain range of rare earth content. With the increase of rare earth content, corten steel coil transforms from cleavage fracture to dimple fracture, and the small spherical rare earth oxygen sulfide inclusion in dimple is the main reason for the transformation.