Elasto-plastic stress analysis on formation mechanism of ghost-lines in cold tolled steel sheet produced from continuously cast slab

摘要

Ghost-lines (CL) observed at polished surfaces of cold rolled sheets, stretched perpendicular to rolling direction, produced from continuously cast slabs were examined in order to investigate formation mechanism. Results obtained were as follows.(1) Degree of GL was influenced by conditions of segregations such as size, intensity, and position in the sheet.(2 ) Simulations of the CL with elasto-plastic stress analysis were carried out under an assumption that there was a difference in stress-strain curves between the sheet matrix and the segregation. It was revealed that a convex part was formed at astretched sheet surface and the convex height was proportional to the size of the segregation and inversely proportional to the depth of the segregation part from the sheet surface. The actual behaviors of the CL in the sheet produced from continuouscasting slab can be quantitatively explained by the calculated results.(3 ) From above, it was concluded that the CL was caused by existence of uneven part of mechanical properties inside the sheet.