Abstract
The effects of aging in the tensile fracture behavior of welded joints of API5L-X52 pipe steel were studied by accelerating aging at 250 °C for different periods of time. The weld metal, heat affected zone and base metal, showed an increase in yield strength while the strain-hardening exponent decreased at early stages of aging. A maximum strength and minimum hardening exponent was found at 500 h due to peak-aging. Subsequently, both properties exhibited an opposite behavior due to over-aging. Tensile fractured specimens for the three different zones exhibited ductile failure, presenting microvoid morphology associated with the coalescence of microcavities. An increase in void density and a reduction in diameter during short periods in the fractured specimens were observed. The maximum density and minimum diameter of voids were obtained at 500 h and were linked to the improvement of strength and precipitation of nanoparticles. Afterward, the fractured surfaces exhibited a reduction in density and the diameters of voids were larger, having been induced by the deterioration of strength and coarsening of particles.
| Original language | English |
|---|---|
| Pages (from-to) | 1561-1568 |
| Number of pages | 8 |
| Journal | Materials Characterization |
| Volume | 60 |
| Issue number | 12 |
| DOIs | |
| State | Published - Dec 2009 |
| Externally published | Yes |
Keywords
- Aging
- Heat affected zone
- Pipe steel
- Tensile test
- Welded joint