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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.

Deep drawing quality high strength (400 MPa grade) cold-rolled steel sheet for automotive use has been developed. This steel sheet is characterized by its chemical composition of extra low carbon, high phosphorus and small niobium together with aluminum. It exhibits very high r̄-value and elongation in tensile test and also an excellent deep draw-ability in small cup test and actual press test of automotive panel parts. The resistance to cold-work embrittlement are improved by controlling the compositions and the cooling rate after final annealing. Spot weldability and the weld performances are very good like as ordinary mild steel sheets. These properties are compared with those of DDQ grade mild steel sheet and previously developed high strength dual phase or rephosphorized steel sheets.