Recent Development of HFW Linepipe With a High-Quality Weld Seam Suitable for Sour Service Environments

2014 ◽  
Author(s):  
Shunsuke Toyoda ◽  
Sota Goto ◽  
Yasushi Kato ◽  
Satoru Yabumoto ◽  
Akio Sato
Keyword(s):  
Crack Propagation ◽  
Chemical Reactions ◽  
Weld Seam ◽  
Welding Process ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Oxide Content ◽  
Electric Resistance ◽  
Diffusible Hydrogen ◽  
High Quality

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.

Metallurgical Design and Performance of HFW Linepipe With a High-Quality Weld Seam Suitable for Sour Services

2013 ◽  
Author(s):  
Shunsuke Toyoda ◽  
Sota Goto ◽  
Takatoshi Okabe ◽  
Hideto Kimura ◽  
Shuichi Sato ◽  
...  
Keyword(s):  
Weld Seam ◽  
Welding Process ◽  
Steel Matrix ◽  
Diffusible Hydrogen ◽  
High Quality ◽  
The Matrix ◽  
Key Factor ◽  
And Performance ◽  
Gasification Reaction ◽  
Crack Initiation Criterion

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.

Effects of Hydrogen Concentration, Specimen Thickness and Loading Frequency on the Hydrogen Enhanced Crack Propagation of Low Alloy Steel

2011 ◽  
Vol 465 ◽  
pp. 519-522
Author(s):  
Yoshiyuki Kondo ◽  
Koshiro Mizobe ◽  
Masanobu Kubota
Keyword(s):  
Crack Propagation ◽  
Alloy Steel ◽  
Hydrogen Concentration ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Specimen Thickness ◽  
Loading Frequency ◽  
Low Alloy Steel ◽  
Diffusible Hydrogen ◽  
Thin Specimen

Crack propagation of SCM440H low alloy steel under varying load is enhanced by absorbed hydrogen. Substantial acceleration of crack propagation rate up to 1000 times was observed compared with that of uncharged material. The role of factors affecting enhanced acceleration was investigated by changing hydrogen concentration absorbed in metal, specimen thickness and loading frequency. Results are as follows. (1) 0.2 mass ppm diffusible hydrogen in metal was enough to cause enhanced acceleration. The predominant fracture mode showing acceleration was quasi cleavage. (2) In the case of thin specimen thinner than 0.8mm, the tri-axiality of stress is weak, and the enhanced crack propagation did not appear. However, the introduction of side-groove to 0.8mm specimen in order to increase the tri-axiality resulted in enhanced acceleration. (3) Lower loading frequency resulted in higher crack propagation rate in cycle domain. The crack propagation rate in time domain was almost constant irrespective of loading frequency. Enough concentration of hydrogen, tri-axiality and low loading frequency resulted in enhanced acceleration of fatigue crack propagation.

Metallurgical Design and Performance of High-Frequency Electric Resistance Welded Linepipe With High-Quality Weld Seam Suitable for Extra-Low-Temperature Services

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Shunsuke Toyoda ◽  
Sota Goto ◽  
Takatoshi Okabe ◽  
Hideto Kimura ◽  
Satoshi Igi
Keyword(s):  
Low Temperature ◽  
High Frequency ◽  
Weld Seam ◽  
Welding Process ◽  
Interface Debonding ◽  
Cleavage Crack ◽  
Maximum Point ◽  
Electric Resistance ◽  
High Quality ◽  
The Matrix

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.

scholarly journals Mode I Crack Propagation Experimental Analysis of Adhesive Bonded Joints Comprising Glass Fibre Composite Material under Impact and Constant Amplitude Fatigue Loading

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4380
Author(s):  
Alirio Andres Bautista Villamil ◽  
Juan Pablo Casas Rodriguez ◽  
Alicia Porras Holguin ◽  
Maribel Silva Barrera
Keyword(s):  
Crack Propagation ◽  
Structural Integrity ◽  
Crack Propagation Rate ◽  
Fatigue Loading ◽  
Propagation Rate ◽  
Operating Conditions ◽  
Impact Testing ◽  
Mode I ◽  
Mode I Crack ◽  
Constant Amplitude

The T-90 Calima is a low-wing monoplane aircraft. Its structure is mainly composed of different components of composite materials, which are mainly bonded by using adhesive joints of different thicknesses. The T-90 Calima is a trainer aircraft; thus, adverse operating conditions such as hard landings, which cause impact loads, may affect the structural integrity of aircrafts. As a result, in this study, the mode I crack propagation rate of a typical adhesive joint of the aircraft is estimated under impact and constant amplitude fatigue loading. To this end, effects of adhesive thickness on the mechanical performance of the joint under quasistatic loading conditions, impact and constant amplitude fatigue in double cantilever beam (DCB) specimens are experimentally investigated. Cyclic impact is induced using a drop-weight impact testing machine to obtain the crack propagation rate (da/dN) as a function of the maximum strain energy release rate (GImax) diagram; likewise, this diagram is also obtained under constant amplitude fatigue, and both diagrams are compared to determine the effect of each type of loading on the structural integrity of the joint. Results reveal that the crack propagation rate under impact fatigue is three orders of magnitude greater than that under constant amplitude fatigue.

scholarly journals Crack Propagation Behavior of a Ni-Based Single-Crystal Superalloy during In Situ SEM Tensile Test at 1000 °C

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1047
Author(s):  
Wenxiang Jiang ◽  
Xiaoyi Ren ◽  
Jinghao Zhao ◽  
Jianli Zhou ◽  
Jinyao Ma ◽  
...  
Keyword(s):  
Crack Propagation ◽  
Tensile Test ◽  
Single Crystal ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Single Crystal Superalloy ◽  
Propagation Path ◽  
Propagation Behavior ◽  
Crack Propagation Behavior

An in situ scanning electron microscope (SEM) tensile test for Ni-based single-crystal superalloy was carried out at 1000 °C. The stress displacement was obtained, and the yield strength and tensile strength of the superalloy were 699 MPa and 826 MPa, respectively. The crack propagation process, consisting of Model I crack and crystallographic shearing crack, was determined. More interestingly, the crack propagation path and rate affected by eutectics was directly observed and counted. Results show that the coalescence of the primary crack and second microcrack at the interface of a γ/γ′ matrix and eutectics would make the crack propagation rate increase from 0.3 μm/s to 0.4 μm/s. On the other hand, crack deflection decreased the rate to 0.05 μm/s. Moreover, movement of dislocations in front of the crack was also analyzed to explain the different crack propagation behavior in the superalloy.

Test Stand for Analysis of Fatigue Crack Propagation under Bending with Torsion

2008 ◽  
Vol 144 ◽  
pp. 90-93 ◽  
Author(s):  
Grzegorz Gasiak ◽  
Grzegorz Robak
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Digital Camera ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Test Stand ◽  
Crack Development ◽  
Fatigue Crack Propagation Rate ◽  
Fatigue Crack Development

The paper presents a test stand for measurements of fatigue crack propagation. The stand includes a fatigue machine MZGS–100 and a device for registration of the crack length. The test stand is equipped with a stereoscopic microscope with fluent magnification of 7× – 67.5×. The microscope can be applied for observation of fatigue crack development. The microscope is also equipped with a digital camera, which enables continuous observation of fatigue crack development on the computer monitor and it is not necessary to stop the machine. The test results obtained at this stand can be used for determination of fatigue life and fatigue crack propagation rate.

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