Elimination of heat pipe in the band structure

Hot-rolled seamless steel tube or by heat expansion of seamless steel metallurgical examination, often found banded structure defects, severe achieve level 4-5. Different parts of the steel pipe sampling inspection results show that the circumferential surface of the pipe band structure is lighter, the bore surface band structure obviously seriously half the thickness of the band structure. In the same material, same process conditions, thick-walled steel pipe in relatively thin-walled banded structure serious. Banded structure is a steel tube defect tissue, when severe banded structure, the mechanical properties of steel apparent anisotropy, the steel pipe section shrinkage rate decreased more lateral, vertical and horizontal impact energy impact energy of about a difference of one times, plastic or steel toughness not meet the technical standards

Requirements, even if the mechanical properties of the steel pipe reached the minimum value of the standard requirements, but the technical agreement on the level of steel in the band structure is also restricted, banded structure also can not pay excessive cargo. In order to eliminate the steel band structure, we conducted several normalizing normalizing and processing, but the results are not ideal. Therefore, to explore low-carbon heat treatment process to eliminate or reduce the deformation of steel banded structure is very urgent task.