Metallugical Design and Performance of ERW Linepipe With High-Quality Weld Seam Suitable for Extra-Low-Temperature Services

Author(s):  
Shunsuke Toyoda ◽  
Sota Goto ◽  
Takatoshi Okabe ◽  
Hideto Kimura ◽  
Satoshi Igi ◽  
...  

To clarify the effect of inclusions on the Charpy impact properties, the 2 mm V-notched Charpy properties of X60 – X80-grades steel were numerically simulated using the finite element method code ABAQUS. The yield strength and the tensile strength of the steel were 562 MPa and 644 MPa, respectively. The striker’s velocity and the temperature dependency of the stress-strain curve were taken into account. To estimate the effect of nonmetallic inclusions, a 200 μm long virtual inclusion with a 1 μm edge radius was situated at the maximum point of the stress triaxiality. Four types of micro crack initiation were determined: (a) ductile void generation in the matrix, (b) cleavage crack generation in the matrix, (c) void generation by inclusion fracture and (d) void generation by matrix-inclusion interface debonding. Without inclusions, a ductile micro void was generated when the striker stroke was 3.3 mm, independent of the temperature. With inclusions, an inclusion fracture occurred when the striker stroke was 0.6 mm at room temperature. The striker stroke decreased as the temperature decreased. Based on the above numerical estimation results, electric resistance welded (ERW) Linepipe with high-quality weld seam MightySeam® has been developed. Controlling the morphology and distribution of oxides generated during the welding process by means of temperature and deformation distribution control is the key factor for improving the low-temperature toughness. The Charpy transition temperature of the developed ERW pipe was much lower than −45°C. Based on the low-temperature hydrostatic burst test with a notched weld seam at −20 °C, the MightySeam® weld provides a fracture performance that is the same as UOE Double Submerged Arc Welded pipe. The pipe has been used in actual, highly demanding, severe environments.

Author(s):  
Shunsuke Toyoda ◽  
Sota Goto ◽  
Takatoshi Okabe ◽  
Hideto Kimura ◽  
Satoshi Igi

To clarify the effect of inclusions on the Charpy impact properties, the 2 mm V-notched Charpy properties of X60–X80-grades steel were numerically simulated using the finite element method code abaqus. The yield strength and the tensile strength of the steel were 562 MPa and 644 MPa, respectively. The striker's velocity and the temperature dependency of the stress–strain curve were taken into account. To estimate the effect of nonmetallic inclusions, a 200 μm long virtual inclusion with a 1 μm edge radius was situated at the maximum point of the stress triaxiality. Four types of microcrack initiation were determined: (a) ductile void generation in the matrix, (b) cleavage crack generation in the matrix, (c) void generation by inclusion fracture, and (d) void generation by matrix–inclusion interface debonding. Without inclusions, a ductile microvoid was generated when the striker stroke was 3.3 mm, independent of the temperature. With inclusions, an inclusion fracture occurred when the striker stroke was 0.6 mm at room temperature. The striker stroke decreased as the temperature decreased. Based on the above numerical estimation results, high-frequency electric resistance welded (HFW) linepipe with high-quality weld seam MightySeam® has been developed. Controlling the morphology and distribution of oxides generated during the welding process by means of temperature and deformation distribution control is the key factor for improving the low-temperature toughness. The Charpy transition temperature of the developed HFW pipe was much lower than −45 °C. Based on the low-temperature hydrostatic burst test with a notched weld seam at −20 °C, the MightySeam® weld provides a fracture performance that is the same as UOE double submerged arc welded pipe. The pipe has been used in actual, highly demanding, and severe environments.


Author(s):  
Shunsuke Toyoda ◽  
Sota Goto ◽  
Takatoshi Okabe ◽  
Hideto Kimura ◽  
Shuichi Sato ◽  
...  

To clarify the effects of inclusions on the sour resistance properties of X60- to X70-grade steel, their resistance to hydrogen-induced cracking (HIC) was numerically simulated. The steel was assumed to have a yield strength of 562 MPa and a tensile strength of 644 MPa for the simulation. To estimate the effect of nonmetallic inclusions, a virtual inclusion was situated at the center of a 10-mm-thick HIC test specimen. Tests were performed using NACE test solution A. The crack initiation criterion was determined as a function of the diffusible hydrogen concentration, the diameter of the inclusion, the edge radius of the inclusion, and the fracture toughness of the matrix after hydrogen absorption. The crack propagation was calculated as a function of the diffusion coefficient of hydrogen in the steel matrix and the gasification reaction ratio of hydrogen at the interface of the steel matrix and the inclusion. Based on the results of the numerical estimation, high-frequency electric resistance welded (HFW) Linepipe with a high-quality weld seam was developed. Controlling the morphology and distribution of oxides generated during the welding process by means of temperature and deformation distribution control is the key factor for improving resistance to HIC.


Author(s):  
Shunsuke Toyoda ◽  
Sota Goto ◽  
Yasushi Kato ◽  
Satoru Yabumoto ◽  
Akio Sato

Based on the appreciable progress being made in quality control and assurance technology for the electric resistance welding process, the number of applications for high-frequency electric resistance welded (HFW) linepipe in highly demanding, severe environments, such as offshore and sour environments, has gradually increased. Resistance to hydrogen-induced cracking (HIC) is the most important property for a linepipe to possess for use in sour environments. However, resistance to HIC, especially along the longitudinal weld seam, has not yet been fully related to metallurgical factors. In this study, to clarify the effects of inclusions on the sour resistance properties of X60- to X70-grade steels, their resistances to HIC were numerically simulated. For the simulation, the steels were assumed to have a yield strength of 562 MPa and a tensile strength of 644 MPa. To estimate the effect of nonmetallic inclusions, a virtual inclusion was situated at the center of a 10-mm-thick HIC test specimen. Tests were performed using NACE test solution A. The crack propagation rate was calculated as a function of the content of diffusible hydrogen, the diameter of the inclusion, and the fracture toughness of the matrix after hydrogen absorption. In the propagation calculation, the resistance to chemical reactions at the interface of the inclusion matrix was also considered to be a delaying factor. By assuming a resistance to chemical reactions at the interface, the crack propagation rate could be fitted to the actual HIC propagation rate. Based on the numerical simulation results, HFW linepipe with a high-quality weld seam was developed. Controlling the morphologies and distributions of oxides generated during the welding process is the key factor for improving the resistance to HIC. Using a combination of optimized chemical composition, microstructure and oxide content, the weld seam of the developed X70-grade HFW steel pipe showed excellent resistance to HIC.


Author(s):  
Satoshi Igi ◽  
Satoru Yabumoto ◽  
Masaki Mitsuya ◽  
Yuya Sumikura ◽  
Mikihiro Takeuchi

A full gas burst test at low temperature below −40°C was performed using a high frequency welded (HFW) linepipe with high-quality weld seam, “MightySeam®,” [1–4] in order to verify the applicability of the Drop Weight Tear Test (DWTT). Residual stress exists in the pipe body of HFW linepipe because the manufacturing method includes a sizing process. Therefore, it is necessary to clarify the difference between the arrestability in the DWTT without residual stress in the specimen and that in the full gas burst test with residual stress in the pipe body. The full gas burst test is performed using a test pipe specimen in which a notch is introduced into the base material by an explosive cutter. In addition, a test pipe specimen with a notch introduced into the weld seam was used in this study because the developed HFW linepipe, “MightySeam®,” has excellent low-temperature toughness as a result of control of the morphology and distribution of oxides generated in the welding process by temperature and deformation distribution control. The Charpy transition temperature of “Mighty Seam®” was much lower than −45 °C. Ductile cracks were initiated from the initial explosive notch, and these cracks were arrested after ductile crack propagation of about 1 m in base material on both sides. The fracture behavior was similar in appearance in the DWTT without residual stress and the full gas burst test with residual stress.


Materia Japan ◽  
2014 ◽  
Vol 53 (3) ◽  
pp. 104-106
Author(s):  
Takatoshi Okabe ◽  
Shunsuke Toyoda ◽  
Yutaka Matsui ◽  
Satoshi Igi ◽  
Satoru Yabumoto

Author(s):  
Satoshi Igi ◽  
Satoru Yabumoto ◽  
Teruki Sadasue ◽  
Hisakazu Tajika ◽  
Kenji Oi

Newly-developed high quality high frequency electric resistance welded (HFW) linepipes have recently been used in pipelines in reel-lay applications and low temperature service environments because of their excellent low temperature weld toughness and cost effectiveness. In order to clarify the applicability of these HFW linepipes to the seismic environment, a series of full-scale tests such as bending test with internal pressure and uniaxial compression test were conducted according to the seismic design code in Japan gas association (JGA). Based on the above-mentioned full-scale tests, the safety performance of high quality HFW linepipe to apply to the seismic region is discussed in comparison with the mechanical properties in the small-scale tests such as the tensile and compression property of the base material and weld seam, especially focused on the strain capacity of HFW linepipe from the view points of full-scale performance and geometrical imperfection. Test results of the bending test with internal pressure and the uniaxial compression were complied with the JGA seismic design code for the permanent ground deformation induced by lateral spreading and surface faults.


Alloy Digest ◽  
1982 ◽  
Vol 31 (1) ◽  

Abstract AISI Type P20 is a chromium-molybdenum tool steel of medium carbon content. It usually is supplied in the prehardened condition (about 300 Brinell) so that the cavity can be machined and the mold or die placed directly in service; however, for some uses further treatments are employed. It is produced to high-quality tool-steel standards to permit a high luster to be achieved on the surface of the polished die cavity. P20 is used for molds for plastics and for die-casting dies for zinc and other low-temperature casting alloys. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on forming, heat treating, and machining. Filing Code: TS-393. Producer or source: Tool steel mills.


2020 ◽  
Vol 39 (1) ◽  
pp. 189-199
Author(s):  
Longbiao Li

AbstractIn this paper, the temperature-dependent matrix multicracking evolution of carbon-fiber-reinforced silicon carbide ceramic-matrix composites (C/SiC CMCs) is investigated. The temperature-dependent composite microstress field is obtained by combining the shear-lag model and temperature-dependent material properties and damage models. The critical matrix strain energy criterion assumes that the strain energy in the matrix has a critical value. With increasing applied stress, when the matrix strain energy is higher than the critical value, more matrix cracks and interface debonding occur to dissipate the additional energy. Based on the composite damage state, the temperature-dependent matrix strain energy and its critical value are obtained. The relationships among applied stress, matrix cracking state, interface damage state, and environmental temperature are established. The effects of interfacial properties, material properties, and environmental temperature on temperature-dependent matrix multiple fracture evolution of C/SiC composites are analyzed. The experimental evolution of matrix multiple fracture and fraction of the interface debonding of C/SiC composites at elevated temperatures are predicted. When the interface shear stress increases, the debonding resistance at the interface increases, leading to the decrease of the debonding fraction at the interface, and the stress transfer capacity between the fiber and the matrix increases, leading to the higher first matrix cracking stress, saturation matrix cracking stress, and saturation matrix cracking density.


2013 ◽  
Vol 690-693 ◽  
pp. 2621-2624
Author(s):  
Bo Chen ◽  
Ji Cai Feng

Underwater weld technology is urgently needed for the widely development of marine recourses, and weld automation technology is the inevitable choice because of the underwater environment. Because of the influence of the rigorous environment, the weld seam forming of underwater wet welding is very poor. To control the weld seam forming automatically, the model between the weld parameters and the weld seam shape must be built. This paper used arc sensor to monitor the electrical information of underwater wet welding process, and regression method was used to model the process, and the factors that influence the weld seam forming mostly were analyzed.


2021 ◽  
pp. 1-16
Author(s):  
Jamie Boon Jun Tay ◽  
Xinying Chua ◽  
Cailing Ang ◽  
Kelvin Kim Tha Goh ◽  
Gomathy Sandhya Subramanian ◽  
...  

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