NLMK Dansteel A/S (Fredriksvaerk, Denmark):

E. A. Goli-Oglu, Cand. Eng., Process Developer, e-mail: EGoli-Oglu@yandex.ru
Z. Greisen, Cand. Eng., Chief Metallurgist

In the first part of the article, a brief overview of the ongoing progress in onshore/offshore wind energy segment is given together with general dimensional descriptions and comparable drawings of the main parts of offshore wind towers used for ~3 and 8–10 MW power wind generators. Comparison in heavy plates dimensions as well as steel grades, which are commonly used for monopile foundations of ~3 MW wind turbines and planned to be used for 8–10 MW wind turbines are presented. The second part contains investigations of the micro hardness level, microstructure and fracture resistance (CTOD test) of industrial samples from a welded joint of low-carbon microalloyed offshore steel heavy plate VL E36 and VL E420 with a thickness of 150 mm after normalization and additional post weld heat treatment (PWHT). The positive effect of PWHT on decreasing the local micro hardness and the increasing of the resistance to brittle fracture of the Grain-Coarsened HAZ of the tested type of the welded joint is presented.

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