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This work aims to study the effect of cold forming on the texture evolution during the manufacturing of rectangular hollow sections. Conventional TMCP steel and a direct-quenched steel in 420 MPa strength level are compared. The texture was characterized at the centerline (S=0) and both surfaces (S=0.8) for base material, four flat side and one corner samples of the rectangular hollow section. The results show that the flat sides of both steels have the minor intensity of ∼{554}<225> and ∼{112}<110> texture components and an intense texture component of ∼{001}<110> in the centerline. Generally, any significant difference between four flat size samples was not found and texture intensities of the conventional TMCP steel were slightly sharper compared to direct-quenched steel. The most important change is observed with the inner corner samples, where the randomly oriented texture in the base material and flat side samples changes to the {110}<111>/<112> shear texture components.

The aim of this work is to study the effect of ageing (250 °C for 1 h) on the mechanical properties of the cold formed S700 rectangular hollow section. The investigated hot rolled steel strip was produced thermomechanical rolling followed by direct quenching. The dimension of the investigated hollow section was 120 x 120 x 10 mm and the corner radii and the other tolerances compliant with EN 10219. Tensile properties and Charpy-V impact toughness were determined for the base material and flat and corner area of the hollow section. The results showed that the tensile strength in the corner was slightly higher in comparison with the flat side, revealing higher cold deformation rate in the corner. Ageing increased the strength level relatively higher than cold forming without losing any elongation properties. The impact energies were at the high level at −40°C and −60°C in cold formed and aged materials. Even at −80°C, the CV results were 118 J/cm2. It is also notable that no difference in CV values between the flat and the corner samples were observed. Thus, the results showed that the flat side specimens testing provides sufficient information of mechanical properties of the cold formed rectangular hollow sections and no need demanding corner sample testing when the structural hollow section is produced by using the thermomechanical controlled and direct-quenched base material. Furthermore, results showed that cold formed S700 is excellent for offshore steels, as steels are used even colder conditions as before.