Weldability Evaluation of Sincron EN 10025-4 S355M Steel Applied in Wind Tower Manufacturing Welding with High Efficiency Process

Abstract

The search for solutions to improve productivity has been the emphasis in relations between the steel industry and the wind tower manufacturers. In this sense, Usiminas, after the implementation of CLC technology (Continuous On-Line Control), has conducted several development projects and implementation of structural steel TMCP (Thermo-Mechanical-Control-Process) with mechanical and metallurgical characteristics differentiated in relation to steels conventionally used by Brazilian industry, especially the wind tower manufacturers. Because of the importance of the welding processes in the manufacture of wind towers, weldability studies are important for the development of procedures and the proper selection of steels and consumables enabling the improvement of welding activities. In this context, this work has the objective of comparative evaluate the weldability of steel Sincron EN 10025-4 S355M (TMCP steels) and ASTM A572 grade 50 (Normalizing steels), when welded by SAW Tandem Arc process using heat inputs higher than those commonly used in wind turbine manufacturing. The results obtained showed that is possible to obtain SAW Tandem Arc welded joints with excellent results for mechanical properties and toughness when employed especially Sincron EN 10025-4 S355M steel, together with combination wire/flux OK Autrod12.22/OK Flux 10.72. The welding procedures evaluated in this work can be an excellent way to increase the productivity in the manufacture of wind towers decreasing the number of pass in longitudinal and circumferential welds.

Key-words:
TMCP Steel; SAW tandem arc; Wind power; Heat affected zone; EBSD