Effect of Pipe Flattening in API X65 Linepipe Steels Having Bainite vs. Ferrite/Pearlite Microstructures
| Autor: | Timothy S. Weeks, John G. Speer, Chester J. Van Tyne, Singon Kang |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
lcsh:TN1-997
Materials science Bainite pipe flattening 02 engineering and technology Flattening 020501 mining & metallurgy pre-strain Ferrite (iron) Ultimate tensile strength General Materials Science steel Composite material lcsh:Mining engineering. Metallurgy Tensile testing bainite ferrite/pearlite tensile test Metals and Alloys Bauschinger effect 021001 nanoscience & nanotechnology Microstructure 0205 materials engineering Pearlite 0210 nano-technology |
| Zdroj: | Metals, Vol 8, Iss 5, p 354 (2018) Metals; Volume 8; Issue 5; Pages: 354 |
| ISSN: | 2075-4701 |
| Popis: | The influence of microstructure on pipe flattening response was assessed using two different commercially produced U-ing, O-ing, and expansion (UOE) pipes from API X65 steels having either a bainitic microstructure (steel B) or a ferrite/pearlite microstructure (steel FP). A four-point bending apparatus and distinctive procedure were used to minimize strain localization during flattening. The flattened specimens were sectioned at different positions through the thickness, and tensile tested in both the longitudinal (LD) and transverse directions (TD) to assess the through-thickness variation in properties. Yield strength (YS) distributions in the LD show V-shaped profiles through thickness in both steels, whereas the YS in the TD nearest the outside diameter (OD) surface is reduced. These variations in YS are due to the Bauschinger effect associated with the compressive flattening pre-strain. The uniform elongation (UE) of steel FP is almost independent of specimen position through the thickness, but for steel B there is a substantial reduction of the UE at both the inside and outside diameter positions and this reduction is greater in the LD. This work confirms that flattened pipe mechanical properties exhibit an important dependence on their microstructure type and it is postulated that the flattening procedure also influences the mechanical properties. |
| Databáze: | OpenAIRE |
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