Modern vehicle bodies make intensive use of high strength steel grades to meet the contradicting demand of lighter weight and simultaneously better mechanical performance. For many steel grades microalloying by niobium is the key to achieve their characteristic property profile. In HSLA steels niobium enhances the strength primarily by grain refinement. In interstitial free high strength steels...

The present study investigates the fracture toughness of FSW X80 HSLA steel welds. Weld cooling rate and peak temperature were varied among welds; indirectly manipulated through travel speed, rpm, weld preheat. Fracture was tested according to ASTM 1820 standard along centerline using surface-notched SEB specimen cooled −40 °C. Results demonstrate that CTOD has a strong inverse linear correlati...

The fracture behavior of a high-strength low-alloy steel subjected to tempforming at 873 K, 923 or 973 K was studied by means impact and bending tests. A decrease in temperature promoted the grain refinement resulting ultrafine grained lamellar-type microstructure with finely dispersed particles that led significant strengthening along an increase toughness. tempformed samples exhibited Charpy ...