Manufacturing Technology 2012, 12(2):217-221 | DOI: 10.21062/ujep/x.2012/a/1213-2489/MT/12/2/217

Fatigue resistance of dual phase steels in presence of microstructural inhomogeneities

Gejza Rosenberg¹, Ľuboš Juhár²

¹ Institute of Materials Research, Slovak Academy of Sciences, Watsonova 47, 040 01 Košice, Slovak Republic

² Unit GM for Research USSE, U. S. Steel Košice, s. r. o, Vstupný areál US Steel Košice, 044 54 Košice, Slovak Republic

In the work, there are noted experimental results aimed at determination of influence of initial microstructure of the steel S355, that was exposed to different temperatures of intercritical annealing, on its resistance against cyclic loading by number of cycles needed to fracture the samples, loaded by stress amplitude σa = 500 MPa. Intercritical annealing at temperature ranging 740-840°C was carried out on a bar with the same thickness as the steel sheet in received state (B=9mm). Fatigue tests were realized on 1,2mm thick specimen cut from subsurface and middle area of initial thickness of the plate, where a banding structure occurred, thickness ∼1,5 mm in the received state. It was discovered, that samples with microstructural banding have higher fatigue resistance independently on temperature of intercritical annealing.

Keywords: dual phase steel, microstructural banding, tensile properties, fatigue resistance

Published: December 1, 2012  Show citation