Surface roughness of steel sheet for automotive use is one of the most important control items, because the surface roughness influences image clarity of painted surface, press formability and easiness in handling during manufacturing and processing of steel sheets.
Laser texturing technology is introduced into a roll finishing process of cold rolling, and new type of regular surface roughness profile can be processed on the surface of steel sheets. Effective application method of this technology is investigated at the present day. In Japan, Laser-textured dull steel sheets are used for outer-panels of automotive body as the first application. And image clarity after painting of outer panels has been successful in improving. Nowadays, Laser texturing technology is actually used for manufacturing the high image clarity steel sheets, and they are manufactured in large quantities.
Another application of Laser texturing technology is for the inner parts which require pressformability. And Laser-textured steel sheets are also actually used for some inner parts.
In this report, according to the technology for improving formability by surface roughness control of steel sheets, the results of basic studies and actual application tests are summarized.