Study on the Cracks of NiTiNb/TC4 Lap Joints Welded by Micro Laser Welding

Chen, Yuhua; Zhan, Zilin; Mao, Yuqing; Yu, Yangyang; Lü, Weiwei

doi:10.1007/978-981-10-7043-3_5

Cited by 4 publications

(1 citation statement)

References 15 publications

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“…However, the higher wire energy and slower cooling rate lead to a weakening of the lowtemperature impact properties of pressure vessel steels in the welding heat-affected zone. This has led to increasing demands on the weldability of metallic materials [6,7]. Therefore, it is necessary to develop a large wire energy welding pressure vessel steel [8,9].…”

Section: Introductionmentioning

confidence: 99%

Effect of Mg Addition on Inclusions in the Welding Heat-Affected Zone of Pressure Vessel Steels

Liu,

Zhang,

Wang

et al. 2023

Materials

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With the development of the pressure vessel industry, high-energy wire welding has a great future. However, this means higher demands on the weldability of pressure vessel steels. Controlling inclusions via oxidative metallurgy is a reliable method of improving the weldability of pressure vessel steels. Hence, in this paper, experimental steels with different Mg element mass fractions were prepared using vacuum metallurgy. Simulated welding for high-heat input welding was carried out using the Gleeble-2000 welding thermal simulation test machine. The inclusions in the welding heat-affected zone (HAZ) in the experimental steels were observed using an optical microscope (OM) and scanning electron microscope (SEM). The compositions of the inclusions were analyzed using an energy-dispersive spectrometer (EDS). The research results indicated that the addition of Mg could increase the number density of the inclusions in the welding HAZ. With the addition of Mg from 0 to 5 wt.%, the total number density of the inclusions increased from 133 to 687 pieces/mm2, and the number density of the inclusions with a size of 0–5 μm2 increased from 122 to 579 pieces/mm2. The inclusions in the experimental steel welding HAZ with Mg elements were mainly elliptical composite inclusions composed of (Mg-Zr-O) + MnS. Moreover, MnS precipitated on the surface of the Mg-containing inclusions in the welding HAZ. Intragranular acicular ferrite (IAF) nucleation was primarily induced via the minimum lattice mismatch mechanism, supplemented with stress-strain energy and inert interface energy mechanisms.

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