Determination and analysis of SHCCT curve of EH36 steel for offshore platform

doi:10.13251/j.issn.0254-6051.2025.01.009

Abstract

Abstract: Offshore platform steel EH36 was taken as the research object, and the welding process of the tested steel was simulated by DIL805L quenching dilatometer. The SHCCT curve of the tested steel was established by means of thermal expansion method combined with metallography method and Vickers hardness test, and the influence of different cooling rates on the microstructure transformation law of the welding heat affected zone was studied. The results show that in the whole cooling rate range, there are four types of microstructure transformation in the HAZ of the tested steel: ferrite+pearlite, ferrite+pearlite+bainite, bainite and martensite+bainite, and the hardness value increases from 164 HV10 to 277 HV10 with the increase of cooling rate. When the cooling rate is lower than 5 ℃/s, the hardness of the HAZ of the tested steel is lower than that of the base metal. In order to ensure that the tested steel obtains good welding joint properties, the cooling rate should be controlled in the range of 10-20 ℃/s (that is, the t_8/5 time is controlled in the range of 15-30 s).

Key words: offshore platform steel, SHCCT curve, welding heat affected zone, Vickers hardness

CLC Number:

TG161

Wang Chengming, Bai Lijuan, Song Yue, Liu Lijun, Gu Xiurui, Li Huimin. Determination and analysis of SHCCT curve of EH36 steel for offshore platform[J]. Heat Treatment of Metals, 2025, 50(1): 58-62.

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