Fracture-Toughness Evaluation in Submerged Arc-Welding Seam Welds in Nonstandard Curved SE(B) Specimens in the Short Radial Direction of API 5L Steel Pipe PDF Download

Author: D. Angeles-Herrera
Publisher:
ISBN:
Category : API 5L steel pipe
Languages : en
Pages : 4

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Book Description
Plane-strain fracture toughness of submerged arc-welding seams of an API 5L steel pipe in the short radial direction was evaluated using nonstandard curved SE(B) test specimens. These specimens are directly cut from the pipe and require no machining other than the crack starter notch. The stress intensity factor function for the nonstandard curved SE(B) specimen was calibrated for three-point bending loading. The initiating notch was aligned to make the crack propagate through the weld-deposited metal zone. The measured fracture-toughness value was 56.3 ± 2.9 Mpa?m. A fractographic study of the tested specimens showed that the deposited metal fracture consists of a mixture of ductile tearing and cleavage that corresponds to the ferrite and the dendritic grains, respectively. The dendritic grains behave in a brittle way, thus being the main contributions to the relatively low fracture-toughness values obtained from the tests.

Author: D. Angeles-Herrera
Publisher:
ISBN:
Category : Metals
Languages : en
Pages : 11

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In this paper, the fracture-toughness and fatigue crack growth rates of the deposited seam weld on the longitudinal pipeline API 5L X52 were evaluated. The study was performed with nonstandard curved specimens, which were machined in the transversal direction of the seam weld with a crack-initiating notch aligned perpendicular to the direction of the deposited seam weld metal. The fractographic analysis showed that the low fracture-toughness of the weld can be attributed to the the existence of elements capable of nucleating brittle fracture and the fact that the intrinsic porosity in the transversal direction provided a favorable crack path for separating the fracture plane, resulting in low fracture-toughness values. Finally, the resistance decrease with respect to the fatigue crack growth was attributed to the small grain size because of the effect of roughness-induced crack closure as well as the interaction of the crack and the inherent porosity.

Author: Robert E. Zinkham
Publisher:
ISBN:
Category : Fracture mechanics
Languages : en
Pages : 124

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Author:
Publisher: ASTM International
ISBN:
Category : Mathematics
Languages : en
Pages : 124

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Author: WJ. Mills
Publisher:
ISBN:
Category : Elevated temperature tests
Languages : en
Pages : 26

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Book Description
The effects of temperature, composition, and weld-process variations on the fracture toughness behavior for Types 308 and 16-8-2 stainless steel (SS) welds were examined using the multiple-specimen J-resistance-curve procedure. Fracture characteristics were found to be dependent on temperature and weld process, but not on filler material. Gas-tungstenarc (GTA) welds exhibited the highest fracture toughness, a shielded-metal-arc (SMA) weld exhibited an intermediate toughness, and submerged-arc (SA) welds yielded the lowest toughness. Minimum expected fracture properties were defined from lower bound fracture toughness and tearing modulus values generated here and in previous studies.

Author: Harry I. McHenry
Publisher: ASTM International
ISBN: 0803112777
Category : Welded joints
Languages : en
Pages : 310

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Fifteen papers from a symposium held in Sparks, Nev., April 1988. They cover: low and high cycle fatigue, fatigue crack growth, corrosion fatigue, fracture toughness testing, and wide-plate testing. Annotation copyright Book News, Inc. Portland, Or.

Author: P. C. Hughes
Publisher:
ISBN:
Category :
Languages : en
Pages : 8

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A series of multi-run submerged arc welds produced with conventional commercial wires and fluxes was evaluated by Charpy V notch and COD tests. Ductile fracture energy is raised and transition temperature lowered by increasing the weld metal Mn/Si ratio to about 2. The COD transition temperature increases with increasing weld metal yield strength. The strain rate sensitivity of the welds, as indicated by the rise in COD transition temperature on testing at a dynamic rather than quasi-static loading rate, increases as weld metal strength decreases. No controlling influence of as-deposited microstructure on fracture toughness was evident in the range of weld metals examined. (Author).

Author: E. Lucon
Publisher:
ISBN:
Category : Crack resistance curves
Languages : en
Pages : 14

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Book Description
The safety and reliability of large-diameter pipelines for the transport of fluid hydrocarbons is being improved by the development of high-strength steels, advanced weld technologies, and strain-based design (SBD) methodologies. In SBD, a limit is imposed on the applied strains rather than the applied stresses. For high-pressure pipelines, SBD requires an assured strength overmatch for the weld metal as compared to the base material, in order to avoid strain localization in the weldment during service. Achieving the required level of strength overmatch, as well as acceptable ductility and low-temperature fracture toughness, is a challenge as the pipe strength increases. Published studies show that low constraint geometries such as single-edge tension [SE(T)] or shallow-notched single-edge bend [SE(B)] specimens represent a better match to the constraint conditions of surface-breaking circumferential cracks in large-diameter pipelines during service (Shen, G., Bouchard, R., Gianetto, J. A., and Tyson, W. R., "Fracture Toughness Evaluation of High Strength Steel Pipe," Proceedings of PVP2008, ASME Pressure Vessel and Piping Division Conference, Chicago, IL, July 27-31, ASME, New York, 2008). However, the SE(T) geometry is not included in any of the most widely used elastic-plastic fracture mechanics (EPFM) test standards. A procedure has been developed for performing and analyzing SE(T) toughness tests using a single-specimen technique that includes formulas for calculating the J-integral and crack-tip opening displacement, as well as for estimating crack size using rotation-corrected elastic unloading compliance. Here, crack-resistance curves and critical toughness values obtained from shallow-crack SE(T) specimens (a0/W ? 0.25) are compared to shallow-crack (a0/W ? 0.25) SE(B) specimens. We believe that the SE(T) methodology is mature enough to be considered for inclusion in future revisions of EPFM standards such as ASTM E1820 and ISO 12135, although additional work is needed to establish validity limits for SE(T) specimens.

Author: RJ. Dexter
Publisher:
ISBN:
Category : Crack-tip opening displacement
Languages : en
Pages : 16

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Book Description
The wet and wet-backed shielded metal-arc welding (SMAW) process can produce welds suitable for structural applications provided fracture control is considered in the design. Welding procedure qualification tests and fracture toughness tests [the ASTM Test for JIc, a Measure of Fracture Toughness (E 813-87)] were performed on the heat-affected zone (HAZ) and weld metal of wet, wet-backed, and dry fillet and groove welds made with (1) A36 steel and E6013 electrodes, and (2) A516 steel and nickel alloy electrodes. Despite Vickers hardness (HV) measurements exceeding 300 HV [xl.O kgf (HV 1.0)] in the HAZ of the ferritic welds and 400 HV in the HAZ of the austenitic welds, no hydrogen cracking or brittle fracture behavior was observed. Generally, the Charpy tests indicated upper-shelf fracture behavior at -2°C (28°F), and the HAZ was found to be tougher than the weld metal. Crack-tip opening displacement (CTOD) estimates were made using British Standard (BS) 5762, and the CTOD was found to be proportional to J even after large crack extension. The maximum load point values of CTOD and J are compared with the initiation values determined by the procedure of ASTM Test E 813. The fracture toughness of the welds is sufficient to be tolerant of flaws much larger than those allowed under American Welding Society (AWS) specifications.

Author: JG. Blaue
Publisher:
ISBN:
Category : Fracture toughness
Languages : en
Pages : 28

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This paper shows that, in the temperature transition regime, scatter of weld metal and heat-affected zone toughness values is related to material heterogeneity in the welded joints. Results were obtained from impact testing of V-notched and fatigue-cracked Charpy specimens as well as from static fracture toughness tests on small-scale and full-thickness specimens. Besides material heterogeneity, mechanical heterogeneity is emphasized as having a significant influence on the fracture performance of heat-affected zone specimens.