A new type of high strength steel for exposed panels - High-strength steel with excellent formability, superior surface precision after press forming, and uniform surface appearance

SFGHITEN&reg (super fine grain, high strength steel sheet), which was developed recently by JFE Steel, is strengthened by fine Nb(C, N) precipitates and grain refinement, giving it excellent press formability suitable for automotive exposed panels. The Nb(C, N) precipitate shows a unique distribution which had not been observed previously and tends to form precipitatedepleted zones, called precipitate free zones (PFZ), in the vicinity of grain boundaries. These PFZs lower yield strength in spite of the small size of the grains. In comparison with conventional deep-drawing sheets, SFGHITEN has a high r-value, combined with excellent resistance to secondary embrittlement imparted by B addition. Try-out pressing for an automotive front-fender model was successfully conducted and demonstrated that the new material has excellent formability, displaying a wider formable range than the conventional steel.