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Effects of welding parameters on microstructure and mechanical properties of underwater wet friction taper plug welded pipeline steel
- Source :
- Welding in the World. 63:11-22
- Publication Year :
- 2018
- Publisher :
- Springer Science and Business Media LLC, 2018.
-
Abstract
- Microstructure and mechanical properties of underwater wet friction taper plug-welded API X52 pipeline steel with 6500–7500-rpm rotational speed at 30–45-kN axial force have been investigated, and the defect-free friction taper plug-welded joints were obtained. It was found that the microstructure in welded joint was remarkably inhomogeneous and very different from the X52 base metal. The weld region could be divided into forged zone (FZ), final frictional plane (FFP), shear deformation zone (SDZ), bonding zone (BZ), and heat-affected zone (HAZ). The HAZ has the coarsest grain and mainly consists of martensite and bainite, and the FZ and SDZ are mainly characterized by a mixture of martensite, bainite, and various shapes of ferrites. The BZ is represented by the banding pattern of fine equi-axed grain ferrites because of local decarbonization around frictional interface in wet welding condition. The axial force has a greater impact on microstructure of welded joint as compared with rotational speed. The hardness profiles measured on cross section of welded joints are severely non-uniform, ranging from 200 to 400 HV1, due to the inhomogeneity of microstructures. The impact absorbed energy of bonding interface sites in welds was considerably lower than that of base metal (about 20% of parent metal) because of the local obviously coarse grain, Widmanstatten ferrites, and banding ferrite defects. The principle of “close mode” friction welding is illustrated, and the microstructural characteristics and mechanical properties of welds can be predicted by judging the type of friction welding.
- Subjects :
- 0209 industrial biotechnology
Materials science
Bainite
Mechanical Engineering
Metals and Alloys
Rotational speed
02 engineering and technology
Welding
Microstructure
020501 mining & metallurgy
law.invention
020901 industrial engineering & automation
0205 materials engineering
Mechanics of Materials
law
Martensite
Ferrite (magnet)
Friction welding
Composite material
Base metal
Subjects
Details
- ISSN :
- 18786669 and 00432288
- Volume :
- 63
- Database :
- OpenAIRE
- Journal :
- Welding in the World
- Accession number :
- edsair.doi...........19b68f08a367b92e4af77b4d7bd0aa38