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Kenneth A Macdonald - One of the best experts on this subject based on the ideXlab platform.
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fatigue analysis of low alloy steel forgings used in the Subsea Industry
International Journal of Fatigue, 2017Co-Authors: Anders Wormsen, Lorents Reinas, Kenneth A Macdonald, Anthony David Muff, Arne Fjeldstad, Finn KirkemoAbstract:Abstract Design S–N curves are presented for low alloy machined steel forgings. Separate S–N curves are given for air and for seawater with cathodic protection. The selection of the S–N curve is made based on the tensile strength and the surface roughness. S–N curves for four tensile strength classes and two surface roughness classes are given. The tensile strength classes cover steels with a tensile strength in the range of 517–793 MPa. The two surface roughness classes cover surface roughnesses up to R a = 6.3 μ m. Separate S–N curves are given for a stress ratio of R = 0 and for a high mean tensile stress. Secondly, a method for adjusting the peak stress in the notch root with respect to the stress gradient is presented. The stress gradient corrected peak stress is used with the presented S–N curves for estimating the fatigue life of fatigue tested notched specimens with typical Subsea design features. All estimated fatigue lives are demonstrably conservative compared to the test results for the wide variety of notched specimens types considered.
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base material fatigue data for low alloy forged steels used in the Subsea Industry part 2 effect of cathodic protection
International Journal of Fatigue, 2015Co-Authors: Anders Wormsen, Marc Avice, Egil Gulbrandsen, Lorents Reinas, Kenneth A Macdonald, Anthony David MuffAbstract:Abstract In air S–N fatigue data for forged low alloy steels as used in the Subsea Industry are presented in Part 1 of this paper. The test scope in Part 1 included testing to quantify the effect of the surface roughness, mean stress and material strength on the high cycle fatigue strength of low alloy steels with a tensile strength in the range of 600–800 MPa. A method for estimating the in air S–N curve from the tensile strength (material grade), surface roughness (machining) and mean stress (such as residual stresses, pressure testing, pre-load and external loads) is presented in Part 1. In this Part 2, fatigue test results for low alloy steels and one carbon steel tested in seawater with cathodic protection with a potential of −1050 mV versus an Ag/AgCl reference electrode are presented. The fatigue testing has been performed using smooth specimens. The tested smooth specimens have (actual) tensile strengths in the range from 627 to 790 MPa. Penalty factors for the tested smooth specimens in seawater with cathodic protection with respect to in air performance (Part 1) are presented and compared with penalty factors used in fatigue design codes such as DNVGL-RP-0005 (former DNV-RP-C203) and BS 7608. The obtained environmental reduction factors are found to be in accordance with the penalty factors used in BS 7608 provided that the maximum stress in the cycle is less than 94% of the yield stress for the material. The penalty factors used for forged steels in DNVGL-RP-0005 are non-conservative compared to the test outcome for the steel tested in an artificial 3.5% NaCl seawater solution. For higher stress levels, larger penalty factors than used in BS 7608 are required. It is found that the obtained S–N based environmental reduction factors are of similar magnitude as BS 7910 fatigue crack growth based reduction factors for CP.
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base material fatigue data for low alloy forged steels used in the Subsea Industry part 1 in air s n data
International Journal of Fatigue, 2015Co-Authors: Anders Wormsen, Marc Avice, Lorents Reinas, Kenneth A Macdonald, Arne Fjeldstad, Anthony David MuffAbstract:Abstract This is the first of two papers presenting fatigue data for low alloy forged steels in a quenched and tempered condition. This paper considers the effect of the surface roughness, mean stress and material strength on the high cycle fatigue crack initiation life on low alloy steels having tensile strengths in the range from 600 to 800 MPa. The scatter in fatigue life has been quantified for the data set consisting of 354 fatigue test results. Fatigue test specimens having surface roughness from R a = 0.3 μ m (polished surface) to R a = 6.3 μ m (coarse production surface, resulting for instance from coarse surface grinding). A method for estimating high cycle fatigue data for smooth low alloy steel from the tensile strength or the Vickers hardness is presented. The estimation method has been validated with fatigue test results and compared with other published methods for estimating strain–life fatigue properties. Part 2 of this paper addresses the effect of seawater with cathodic protection on the fatigue crack initiation life for smooth specimens.
Anthony David Muff - One of the best experts on this subject based on the ideXlab platform.
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fatigue analysis of low alloy steel forgings used in the Subsea Industry
International Journal of Fatigue, 2017Co-Authors: Anders Wormsen, Lorents Reinas, Kenneth A Macdonald, Anthony David Muff, Arne Fjeldstad, Finn KirkemoAbstract:Abstract Design S–N curves are presented for low alloy machined steel forgings. Separate S–N curves are given for air and for seawater with cathodic protection. The selection of the S–N curve is made based on the tensile strength and the surface roughness. S–N curves for four tensile strength classes and two surface roughness classes are given. The tensile strength classes cover steels with a tensile strength in the range of 517–793 MPa. The two surface roughness classes cover surface roughnesses up to R a = 6.3 μ m. Separate S–N curves are given for a stress ratio of R = 0 and for a high mean tensile stress. Secondly, a method for adjusting the peak stress in the notch root with respect to the stress gradient is presented. The stress gradient corrected peak stress is used with the presented S–N curves for estimating the fatigue life of fatigue tested notched specimens with typical Subsea design features. All estimated fatigue lives are demonstrably conservative compared to the test results for the wide variety of notched specimens types considered.
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base material fatigue data for low alloy forged steels used in the Subsea Industry part 2 effect of cathodic protection
International Journal of Fatigue, 2015Co-Authors: Anders Wormsen, Marc Avice, Egil Gulbrandsen, Lorents Reinas, Kenneth A Macdonald, Anthony David MuffAbstract:Abstract In air S–N fatigue data for forged low alloy steels as used in the Subsea Industry are presented in Part 1 of this paper. The test scope in Part 1 included testing to quantify the effect of the surface roughness, mean stress and material strength on the high cycle fatigue strength of low alloy steels with a tensile strength in the range of 600–800 MPa. A method for estimating the in air S–N curve from the tensile strength (material grade), surface roughness (machining) and mean stress (such as residual stresses, pressure testing, pre-load and external loads) is presented in Part 1. In this Part 2, fatigue test results for low alloy steels and one carbon steel tested in seawater with cathodic protection with a potential of −1050 mV versus an Ag/AgCl reference electrode are presented. The fatigue testing has been performed using smooth specimens. The tested smooth specimens have (actual) tensile strengths in the range from 627 to 790 MPa. Penalty factors for the tested smooth specimens in seawater with cathodic protection with respect to in air performance (Part 1) are presented and compared with penalty factors used in fatigue design codes such as DNVGL-RP-0005 (former DNV-RP-C203) and BS 7608. The obtained environmental reduction factors are found to be in accordance with the penalty factors used in BS 7608 provided that the maximum stress in the cycle is less than 94% of the yield stress for the material. The penalty factors used for forged steels in DNVGL-RP-0005 are non-conservative compared to the test outcome for the steel tested in an artificial 3.5% NaCl seawater solution. For higher stress levels, larger penalty factors than used in BS 7608 are required. It is found that the obtained S–N based environmental reduction factors are of similar magnitude as BS 7910 fatigue crack growth based reduction factors for CP.
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base material fatigue data for low alloy forged steels used in the Subsea Industry part 1 in air s n data
International Journal of Fatigue, 2015Co-Authors: Anders Wormsen, Marc Avice, Lorents Reinas, Kenneth A Macdonald, Arne Fjeldstad, Anthony David MuffAbstract:Abstract This is the first of two papers presenting fatigue data for low alloy forged steels in a quenched and tempered condition. This paper considers the effect of the surface roughness, mean stress and material strength on the high cycle fatigue crack initiation life on low alloy steels having tensile strengths in the range from 600 to 800 MPa. The scatter in fatigue life has been quantified for the data set consisting of 354 fatigue test results. Fatigue test specimens having surface roughness from R a = 0.3 μ m (polished surface) to R a = 6.3 μ m (coarse production surface, resulting for instance from coarse surface grinding). A method for estimating high cycle fatigue data for smooth low alloy steel from the tensile strength or the Vickers hardness is presented. The estimation method has been validated with fatigue test results and compared with other published methods for estimating strain–life fatigue properties. Part 2 of this paper addresses the effect of seawater with cathodic protection on the fatigue crack initiation life for smooth specimens.
Anders Wormsen - One of the best experts on this subject based on the ideXlab platform.
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fatigue analysis of low alloy steel forgings used in the Subsea Industry
International Journal of Fatigue, 2017Co-Authors: Anders Wormsen, Lorents Reinas, Kenneth A Macdonald, Anthony David Muff, Arne Fjeldstad, Finn KirkemoAbstract:Abstract Design S–N curves are presented for low alloy machined steel forgings. Separate S–N curves are given for air and for seawater with cathodic protection. The selection of the S–N curve is made based on the tensile strength and the surface roughness. S–N curves for four tensile strength classes and two surface roughness classes are given. The tensile strength classes cover steels with a tensile strength in the range of 517–793 MPa. The two surface roughness classes cover surface roughnesses up to R a = 6.3 μ m. Separate S–N curves are given for a stress ratio of R = 0 and for a high mean tensile stress. Secondly, a method for adjusting the peak stress in the notch root with respect to the stress gradient is presented. The stress gradient corrected peak stress is used with the presented S–N curves for estimating the fatigue life of fatigue tested notched specimens with typical Subsea design features. All estimated fatigue lives are demonstrably conservative compared to the test results for the wide variety of notched specimens types considered.
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Tensile Testing and Analysis of Notched Low Alloy Steel Specimens
Volume 5: High-Pressure Technology; Rudy Scavuzzo Student Paper Symposium and 24th Annual Student Paper Competition; ASME Nondestructive Evaluation Di, 2016Co-Authors: Anders Wormsen, Finn Kirkemo, Torulf HagnerAbstract:Notched axisymmetric specimens of two high strength low alloy steels used frequently in the Subsea Industry have been tensile tested to failure in air and in a 3.5% NaCl artificial seawater solution with cathodic protection (CP). The aim of the testing was to provide input to an initial assessment of elastic-plastic static load-capacity analysis of low alloy steels with material and quality control requirements according to ISO 13628-7 (ISO-7). The tensile testing in seawater with CP was performed in order to investigate whether hydrogen as formed by the CP system may have an effect on the ductility and strength that needs to be taken into account in the static load-capacity analysis and hence in design. Local and global static load-capacity criteria from ASME VIII Div. 3 (Div.3), ISO-7, NORSOK U-001 (U-001) and API 6X (6X) have been considered for the notched specimens. Recommendations regarding elastic-plastic static load-capacity analysis of Subsea equipment are given. The specimens tested in seawater with CP were found to have a reduced ductility and strength compared to the corresponding specimens tested in air. Further testing in seawater with CP is recommended before it can be concluded whether the environmental effect of the hydrogen needs to be included in the static load-capacity analysis of high strength low alloy steels.
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base material fatigue data for low alloy forged steels used in the Subsea Industry part 2 effect of cathodic protection
International Journal of Fatigue, 2015Co-Authors: Anders Wormsen, Marc Avice, Egil Gulbrandsen, Lorents Reinas, Kenneth A Macdonald, Anthony David MuffAbstract:Abstract In air S–N fatigue data for forged low alloy steels as used in the Subsea Industry are presented in Part 1 of this paper. The test scope in Part 1 included testing to quantify the effect of the surface roughness, mean stress and material strength on the high cycle fatigue strength of low alloy steels with a tensile strength in the range of 600–800 MPa. A method for estimating the in air S–N curve from the tensile strength (material grade), surface roughness (machining) and mean stress (such as residual stresses, pressure testing, pre-load and external loads) is presented in Part 1. In this Part 2, fatigue test results for low alloy steels and one carbon steel tested in seawater with cathodic protection with a potential of −1050 mV versus an Ag/AgCl reference electrode are presented. The fatigue testing has been performed using smooth specimens. The tested smooth specimens have (actual) tensile strengths in the range from 627 to 790 MPa. Penalty factors for the tested smooth specimens in seawater with cathodic protection with respect to in air performance (Part 1) are presented and compared with penalty factors used in fatigue design codes such as DNVGL-RP-0005 (former DNV-RP-C203) and BS 7608. The obtained environmental reduction factors are found to be in accordance with the penalty factors used in BS 7608 provided that the maximum stress in the cycle is less than 94% of the yield stress for the material. The penalty factors used for forged steels in DNVGL-RP-0005 are non-conservative compared to the test outcome for the steel tested in an artificial 3.5% NaCl seawater solution. For higher stress levels, larger penalty factors than used in BS 7608 are required. It is found that the obtained S–N based environmental reduction factors are of similar magnitude as BS 7910 fatigue crack growth based reduction factors for CP.
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base material fatigue data for low alloy forged steels used in the Subsea Industry part 1 in air s n data
International Journal of Fatigue, 2015Co-Authors: Anders Wormsen, Marc Avice, Lorents Reinas, Kenneth A Macdonald, Arne Fjeldstad, Anthony David MuffAbstract:Abstract This is the first of two papers presenting fatigue data for low alloy forged steels in a quenched and tempered condition. This paper considers the effect of the surface roughness, mean stress and material strength on the high cycle fatigue crack initiation life on low alloy steels having tensile strengths in the range from 600 to 800 MPa. The scatter in fatigue life has been quantified for the data set consisting of 354 fatigue test results. Fatigue test specimens having surface roughness from R a = 0.3 μ m (polished surface) to R a = 6.3 μ m (coarse production surface, resulting for instance from coarse surface grinding). A method for estimating high cycle fatigue data for smooth low alloy steel from the tensile strength or the Vickers hardness is presented. The estimation method has been validated with fatigue test results and compared with other published methods for estimating strain–life fatigue properties. Part 2 of this paper addresses the effect of seawater with cathodic protection on the fatigue crack initiation life for smooth specimens.
Lorents Reinas - One of the best experts on this subject based on the ideXlab platform.
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fatigue analysis of low alloy steel forgings used in the Subsea Industry
International Journal of Fatigue, 2017Co-Authors: Anders Wormsen, Lorents Reinas, Kenneth A Macdonald, Anthony David Muff, Arne Fjeldstad, Finn KirkemoAbstract:Abstract Design S–N curves are presented for low alloy machined steel forgings. Separate S–N curves are given for air and for seawater with cathodic protection. The selection of the S–N curve is made based on the tensile strength and the surface roughness. S–N curves for four tensile strength classes and two surface roughness classes are given. The tensile strength classes cover steels with a tensile strength in the range of 517–793 MPa. The two surface roughness classes cover surface roughnesses up to R a = 6.3 μ m. Separate S–N curves are given for a stress ratio of R = 0 and for a high mean tensile stress. Secondly, a method for adjusting the peak stress in the notch root with respect to the stress gradient is presented. The stress gradient corrected peak stress is used with the presented S–N curves for estimating the fatigue life of fatigue tested notched specimens with typical Subsea design features. All estimated fatigue lives are demonstrably conservative compared to the test results for the wide variety of notched specimens types considered.
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base material fatigue data for low alloy forged steels used in the Subsea Industry part 2 effect of cathodic protection
International Journal of Fatigue, 2015Co-Authors: Anders Wormsen, Marc Avice, Egil Gulbrandsen, Lorents Reinas, Kenneth A Macdonald, Anthony David MuffAbstract:Abstract In air S–N fatigue data for forged low alloy steels as used in the Subsea Industry are presented in Part 1 of this paper. The test scope in Part 1 included testing to quantify the effect of the surface roughness, mean stress and material strength on the high cycle fatigue strength of low alloy steels with a tensile strength in the range of 600–800 MPa. A method for estimating the in air S–N curve from the tensile strength (material grade), surface roughness (machining) and mean stress (such as residual stresses, pressure testing, pre-load and external loads) is presented in Part 1. In this Part 2, fatigue test results for low alloy steels and one carbon steel tested in seawater with cathodic protection with a potential of −1050 mV versus an Ag/AgCl reference electrode are presented. The fatigue testing has been performed using smooth specimens. The tested smooth specimens have (actual) tensile strengths in the range from 627 to 790 MPa. Penalty factors for the tested smooth specimens in seawater with cathodic protection with respect to in air performance (Part 1) are presented and compared with penalty factors used in fatigue design codes such as DNVGL-RP-0005 (former DNV-RP-C203) and BS 7608. The obtained environmental reduction factors are found to be in accordance with the penalty factors used in BS 7608 provided that the maximum stress in the cycle is less than 94% of the yield stress for the material. The penalty factors used for forged steels in DNVGL-RP-0005 are non-conservative compared to the test outcome for the steel tested in an artificial 3.5% NaCl seawater solution. For higher stress levels, larger penalty factors than used in BS 7608 are required. It is found that the obtained S–N based environmental reduction factors are of similar magnitude as BS 7910 fatigue crack growth based reduction factors for CP.
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base material fatigue data for low alloy forged steels used in the Subsea Industry part 1 in air s n data
International Journal of Fatigue, 2015Co-Authors: Anders Wormsen, Marc Avice, Lorents Reinas, Kenneth A Macdonald, Arne Fjeldstad, Anthony David MuffAbstract:Abstract This is the first of two papers presenting fatigue data for low alloy forged steels in a quenched and tempered condition. This paper considers the effect of the surface roughness, mean stress and material strength on the high cycle fatigue crack initiation life on low alloy steels having tensile strengths in the range from 600 to 800 MPa. The scatter in fatigue life has been quantified for the data set consisting of 354 fatigue test results. Fatigue test specimens having surface roughness from R a = 0.3 μ m (polished surface) to R a = 6.3 μ m (coarse production surface, resulting for instance from coarse surface grinding). A method for estimating high cycle fatigue data for smooth low alloy steel from the tensile strength or the Vickers hardness is presented. The estimation method has been validated with fatigue test results and compared with other published methods for estimating strain–life fatigue properties. Part 2 of this paper addresses the effect of seawater with cathodic protection on the fatigue crack initiation life for smooth specimens.
Marc Avice - One of the best experts on this subject based on the ideXlab platform.
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base material fatigue data for low alloy forged steels used in the Subsea Industry part 2 effect of cathodic protection
International Journal of Fatigue, 2015Co-Authors: Anders Wormsen, Marc Avice, Egil Gulbrandsen, Lorents Reinas, Kenneth A Macdonald, Anthony David MuffAbstract:Abstract In air S–N fatigue data for forged low alloy steels as used in the Subsea Industry are presented in Part 1 of this paper. The test scope in Part 1 included testing to quantify the effect of the surface roughness, mean stress and material strength on the high cycle fatigue strength of low alloy steels with a tensile strength in the range of 600–800 MPa. A method for estimating the in air S–N curve from the tensile strength (material grade), surface roughness (machining) and mean stress (such as residual stresses, pressure testing, pre-load and external loads) is presented in Part 1. In this Part 2, fatigue test results for low alloy steels and one carbon steel tested in seawater with cathodic protection with a potential of −1050 mV versus an Ag/AgCl reference electrode are presented. The fatigue testing has been performed using smooth specimens. The tested smooth specimens have (actual) tensile strengths in the range from 627 to 790 MPa. Penalty factors for the tested smooth specimens in seawater with cathodic protection with respect to in air performance (Part 1) are presented and compared with penalty factors used in fatigue design codes such as DNVGL-RP-0005 (former DNV-RP-C203) and BS 7608. The obtained environmental reduction factors are found to be in accordance with the penalty factors used in BS 7608 provided that the maximum stress in the cycle is less than 94% of the yield stress for the material. The penalty factors used for forged steels in DNVGL-RP-0005 are non-conservative compared to the test outcome for the steel tested in an artificial 3.5% NaCl seawater solution. For higher stress levels, larger penalty factors than used in BS 7608 are required. It is found that the obtained S–N based environmental reduction factors are of similar magnitude as BS 7910 fatigue crack growth based reduction factors for CP.
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base material fatigue data for low alloy forged steels used in the Subsea Industry part 1 in air s n data
International Journal of Fatigue, 2015Co-Authors: Anders Wormsen, Marc Avice, Lorents Reinas, Kenneth A Macdonald, Arne Fjeldstad, Anthony David MuffAbstract:Abstract This is the first of two papers presenting fatigue data for low alloy forged steels in a quenched and tempered condition. This paper considers the effect of the surface roughness, mean stress and material strength on the high cycle fatigue crack initiation life on low alloy steels having tensile strengths in the range from 600 to 800 MPa. The scatter in fatigue life has been quantified for the data set consisting of 354 fatigue test results. Fatigue test specimens having surface roughness from R a = 0.3 μ m (polished surface) to R a = 6.3 μ m (coarse production surface, resulting for instance from coarse surface grinding). A method for estimating high cycle fatigue data for smooth low alloy steel from the tensile strength or the Vickers hardness is presented. The estimation method has been validated with fatigue test results and compared with other published methods for estimating strain–life fatigue properties. Part 2 of this paper addresses the effect of seawater with cathodic protection on the fatigue crack initiation life for smooth specimens.
