期刊
METALS
卷 8, 期 12, 页码 -出版社
MDPI
DOI: 10.3390/met8121007
关键词
weldments; cladding; weld overlay; dissimilar transition zone; interface of dissimilar metals; type II boundary; electron backscatter diffraction (EBSD); cryogenic steel; corrosion resistant alloy; CO2 injection unit
资金
- Shell Brasil Ltd. [TO821]
- Empresa Brasileira de Pesquisa e Inovacao Industrial-Embrapii [PCCOP1512.0004]
9%Ni steel was recently used for the first time in the field of injection unit (IU) for the injection of CO2 into oil wells. Because such steels are operated in H2S medium and are susceptible to sulfide stress cracking, their pipes are cladded with Ni-based superalloy 625 by using gas tungsten arc welding with a hot wire to prevent this phenomenon from occurring. The transition zone of substrate/clad can have high hardness and low toughness, and promote failure of the component during service; therefore, it is very important to know its characteristics. In this work, this transition zone was analyzed through optical and scanning electron microscopy with energy dispersive X-ray spectrometry and electron backscatter diffraction, as well as Vickers microhardness, shear and bend tests. Metallographic analysis identified type I and II boundaries with distinct chemical gradients, MC-type carbides, Laves/gamma eutectics, peninsulas macrosegregation, crystallographic texture close to < 100 > in the clads, residual strain, and drop of microhardness across the transition zone. The dads were approved in the shear and bend tests. This work proposes a new type II boundary formation mechanism in dissimilar welds of steels that do not exhibit the allotropic transformation delta ->gamma during the welding thermal cycle and do not experience a change in the solidification mode.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据