Weldability of accelerated-cooled (AcC) high strength TMCP steel X80

Pekka Nevasmaa, Mark Cederberg, Martti Vilpas

Research output: Book/ReportReportProfessional

Abstract

The report gives and briefly discusses the test results obtained in welding and weldability tests of an accelerated-cooled pipe-line steel AcC X80. The tests comprised of mechanical testing of joints welded with arc energies ranging from 15 to 50 kJ/cm using SAW and FCAW processes. Also the results of weld thermal simulation and Implant weldability tests for the steel are reported and discussed. The results demonstrate the improved weldability of the AcC X80 steel, as compared to conventional normalized or QT steels of similar strength level. Even in heavily restrained butt-welded joints representing the most severe conditions in pipe-line field welding, welding without preheat was possible up to 15 and 25 mm plate thickness using arc energies of 10 and 22 kJ/cm, respectively. Provided that re-dried low-hydrogen consumables were used, no weld metal cracking was observed in the heat input range studied in this X80 class although welding was performed without preheat. In the majority of cases, all the welded joints failed to meet the toughness requirement (40 J/-40°C) all through the arc energy range from 15 to 50 kJ/cm. Adequate HAZ impact toughness was obtained only in one of the joints welded with a low arc energy of 15 kJ/cm. Weld metal toughness was acceptable, although a decrease in toughness was evident towards higher heat inputs. Surprisingly, the use of 0.4% Mo-Ti-B-alloyed SAW-filler material with an arc energy of 50 kJ/cm led to a drastic degradation in toughness of the two-pass weld metal. Any clear relationship between HAZ toughness and arc energy could not be derived owing to the anomalous low HAZ impact energy values through the whole arc energy range studied. Also the Charpy-V tests of simulated HAZ confirmed a deterioration in HAZ toughness at -40°C through the whole cooling time range t<MV%0>8/5<D> of 12 to 52 sec. However, Charpy-V test data from real HAZ suggested that some improvement could be expected at higher temperatures of -20°C, when limiting the maximum allowable heat input below 15 kJ/cm.
Original languageEnglish
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
Number of pages40
ISBN (Print)951-38-4307-6
Publication statusPublished - 1992
MoE publication typeNot Eligible

Publication series

NameVTT Tiedotteita - Meddelanden - Research Notes
PublisherVTT
No.1413
ISSN (Print)1235-0605
ISSN (Electronic)1455-0865

Fingerprint

Weldability
High strength steel
Welds
Toughness
Welding
Steel
Flux-cored arc welding (FCAW)
Metals
Pipe
Mechanical testing
Heat affected zone
Deterioration
Fillers
Fracture toughness
Cooling
Degradation
Hydrogen
Hot Temperature

Keywords

  • welded joints
  • butt welds
  • high strength steels
  • thermochemical treatment
  • weldability
  • arc seam welds
  • arc welding
  • toughness
  • impact strength
  • mechanical properties

Cite this

Nevasmaa, P., Cederberg, M., & Vilpas, M. (1992). Weldability of accelerated-cooled (AcC) high strength TMCP steel X80. Espoo: VTT Technical Research Centre of Finland. VTT Tiedotteita - Meddelanden - Research Notes, No. 1413
Nevasmaa, Pekka ; Cederberg, Mark ; Vilpas, Martti. / Weldability of accelerated-cooled (AcC) high strength TMCP steel X80. Espoo : VTT Technical Research Centre of Finland, 1992. 40 p. (VTT Tiedotteita - Meddelanden - Research Notes; No. 1413).
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Nevasmaa, P, Cederberg, M & Vilpas, M 1992, Weldability of accelerated-cooled (AcC) high strength TMCP steel X80. VTT Tiedotteita - Meddelanden - Research Notes, no. 1413, VTT Technical Research Centre of Finland, Espoo.

Weldability of accelerated-cooled (AcC) high strength TMCP steel X80. / Nevasmaa, Pekka; Cederberg, Mark; Vilpas, Martti.

Espoo : VTT Technical Research Centre of Finland, 1992. 40 p. (VTT Tiedotteita - Meddelanden - Research Notes; No. 1413).

Research output: Book/ReportReportProfessional

TY - BOOK

T1 - Weldability of accelerated-cooled (AcC) high strength TMCP steel X80

AU - Nevasmaa, Pekka

AU - Cederberg, Mark

AU - Vilpas, Martti

PY - 1992

Y1 - 1992

N2 - The report gives and briefly discusses the test results obtained in welding and weldability tests of an accelerated-cooled pipe-line steel AcC X80. The tests comprised of mechanical testing of joints welded with arc energies ranging from 15 to 50 kJ/cm using SAW and FCAW processes. Also the results of weld thermal simulation and Implant weldability tests for the steel are reported and discussed. The results demonstrate the improved weldability of the AcC X80 steel, as compared to conventional normalized or QT steels of similar strength level. Even in heavily restrained butt-welded joints representing the most severe conditions in pipe-line field welding, welding without preheat was possible up to 15 and 25 mm plate thickness using arc energies of 10 and 22 kJ/cm, respectively. Provided that re-dried low-hydrogen consumables were used, no weld metal cracking was observed in the heat input range studied in this X80 class although welding was performed without preheat. In the majority of cases, all the welded joints failed to meet the toughness requirement (40 J/-40°C) all through the arc energy range from 15 to 50 kJ/cm. Adequate HAZ impact toughness was obtained only in one of the joints welded with a low arc energy of 15 kJ/cm. Weld metal toughness was acceptable, although a decrease in toughness was evident towards higher heat inputs. Surprisingly, the use of 0.4% Mo-Ti-B-alloyed SAW-filler material with an arc energy of 50 kJ/cm led to a drastic degradation in toughness of the two-pass weld metal. Any clear relationship between HAZ toughness and arc energy could not be derived owing to the anomalous low HAZ impact energy values through the whole arc energy range studied. Also the Charpy-V tests of simulated HAZ confirmed a deterioration in HAZ toughness at -40°C through the whole cooling time range t<MV%0>8/5<D> of 12 to 52 sec. However, Charpy-V test data from real HAZ suggested that some improvement could be expected at higher temperatures of -20°C, when limiting the maximum allowable heat input below 15 kJ/cm.

AB - The report gives and briefly discusses the test results obtained in welding and weldability tests of an accelerated-cooled pipe-line steel AcC X80. The tests comprised of mechanical testing of joints welded with arc energies ranging from 15 to 50 kJ/cm using SAW and FCAW processes. Also the results of weld thermal simulation and Implant weldability tests for the steel are reported and discussed. The results demonstrate the improved weldability of the AcC X80 steel, as compared to conventional normalized or QT steels of similar strength level. Even in heavily restrained butt-welded joints representing the most severe conditions in pipe-line field welding, welding without preheat was possible up to 15 and 25 mm plate thickness using arc energies of 10 and 22 kJ/cm, respectively. Provided that re-dried low-hydrogen consumables were used, no weld metal cracking was observed in the heat input range studied in this X80 class although welding was performed without preheat. In the majority of cases, all the welded joints failed to meet the toughness requirement (40 J/-40°C) all through the arc energy range from 15 to 50 kJ/cm. Adequate HAZ impact toughness was obtained only in one of the joints welded with a low arc energy of 15 kJ/cm. Weld metal toughness was acceptable, although a decrease in toughness was evident towards higher heat inputs. Surprisingly, the use of 0.4% Mo-Ti-B-alloyed SAW-filler material with an arc energy of 50 kJ/cm led to a drastic degradation in toughness of the two-pass weld metal. Any clear relationship between HAZ toughness and arc energy could not be derived owing to the anomalous low HAZ impact energy values through the whole arc energy range studied. Also the Charpy-V tests of simulated HAZ confirmed a deterioration in HAZ toughness at -40°C through the whole cooling time range t<MV%0>8/5<D> of 12 to 52 sec. However, Charpy-V test data from real HAZ suggested that some improvement could be expected at higher temperatures of -20°C, when limiting the maximum allowable heat input below 15 kJ/cm.

KW - welded joints

KW - butt welds

KW - high strength steels

KW - thermochemical treatment

KW - weldability

KW - arc seam welds

KW - arc welding

KW - toughness

KW - impact strength

KW - mechanical properties

M3 - Report

SN - 951-38-4307-6

T3 - VTT Tiedotteita - Meddelanden - Research Notes

BT - Weldability of accelerated-cooled (AcC) high strength TMCP steel X80

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Nevasmaa P, Cederberg M, Vilpas M. Weldability of accelerated-cooled (AcC) high strength TMCP steel X80. Espoo: VTT Technical Research Centre of Finland, 1992. 40 p. (VTT Tiedotteita - Meddelanden - Research Notes; No. 1413).