Laser and mechanical cutting effects on the cut-edge properties of steel S355N. (June 2017)

• Record Type: Journal Article
• Authors: Bursi, Oreste S.; D'Incau, Mirco; Zanon, Gabriele; Raso, Sergio; Scardi, Paolo
• Is Part Of: Journal of constructional steel research. Volume 133(2017)
• Page Start: 181
• Page End: 191
• Publication Date: 2017-06
• Subjects: Straight cut-edge -- Round cut-hole -- Laser thermal cutting -- Microstructure -- Hardness -- Residual stress -- EN 1090 -- Eurocode 3 FAT class; Steel, Structural -- Periodicals; Building, Iron and steel -- Periodicals; Acier de construction -- Périodiques; Construction métallique -- Périodiques; 624.1821
• DOI: 10.1016/j.jcsr.2017.02.012
• Languages: English
• ISSNs: 0143-974X

Abstract

Abstract: The execution of steel structures was recently regulated by the standard EN 1090 that introduced both the concept of execution class and minimum requirements for elements processed by cutting techniques such oxy-fuel, plasma and laser cutting. The last technique is especially appealing for structural details characterized by complex geometries and high precision machining. With these premises, this work compares several properties of S355N steel plates machined by traditional mechanical versus laser cutting, in view of the limitations provided by EN 1090 on local hardness HV10 of straight cutting surfaces and high-cycle fatigue applications. In particular, the microstructural characterization included optical and electron microscopy, microhardness, hardness and residual stress analysis on cut edges of 5 and 15 mm S355N steel plates. Moreover, the high-cycle fatigue behaviour was studied both in base material coupons and elemental bolted connections. Whilst the mill and drill cutting entailed straight and round cut edges with superior properties, material and high-cycle fatigue properties of edges obtained by laser cutting satisfied both EN1090 requirements and the Eurocode 3 FAT classes. Highlights: Comparison of both mechanical and laser cutting applied to workpieces extracted from structural steel S355 N. Specimens made with mechanical cutting performed generally better than specimens treated with laser cutting. Microstructures and material properties of laser cutting resulted to be favourable. Code requirements were also met for high-cycle fatigue applications. The fatigue category for drilled holes, i.e. FAT90, resulted to be adequate for laser cut elemental bolted connections.