Microstructure, Mechanical Properties and SSC Susceptibility of Multiple SMAW Repairs in Line Pipe Girth Welds

2008 ◽  
Author(s):  
Oscar E. Vega ◽  
Jose´ M. Hallen ◽  
Agusti´n Villagomez ◽  
Antonio Contreras
Keyword(s):  
Heat Affected Zone ◽  
Welded Joints ◽  
Impact Resistance ◽  
Microstructural Characterization ◽  
Coarse Grained ◽  
Shielded Metal Arc Welding ◽  
Line Pipe ◽  
Metal Arc Welding ◽  
Sulfide Stress ◽  
Girth Welds

Girth welds of seamless API X52 steel pipe containing multiple shielded metal arc welding (SMAW) repairs and one as-welded condition were studied. Microstructural characterization, mechanical behavior and sulfide stress corrosion cracking (SSC) susceptibility of the welded joints were evaluated by means of optical and scanning electron microscopy, hardness, tension, Charpy-V impact resistance and slow strain rate tests (SSRT). The results of this work indicate that increasing the number of welding repairs promotes grain growth in the heat affected zone (HAZ). The yield strength (YS) and ultimate tensile strength (UTS) for the different welding repairs satisfy the specified minimum values of the material. Significant reduction in Charpy-V impact resistance with the increases of the number of repairs was found in the coarse grained heat affected zone (CGHAZ). A high susceptibility to SSC was exhibited by the welded joints and the intercritical heat affected zone was the most susceptible area to SSC.

scholarly journals Shielded Metal Arc and Thermite Welding Effect to Residual Stress, Hardness and Crack of R54-Rail Weld Joint

2020 ◽  
Vol 55 (4) ◽  
Author(s):  
Yurianto ◽  
Gunawan Dwi Haryadi ◽  
Sri Nugroho ◽  
Sulardjaka ◽  
Susilo Adi Widayanto
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Welded Joints ◽  
Arc Welding ◽  
Welding Process ◽  
Shielded Metal Arc Welding ◽  
Metal Arc Welding ◽  
Crack Susceptibility

The heating and cooling at the end of the welding process can cause residual stresses that are permanent and remain in the welded joint. This study aims to evaluate the magnitude and direction of residual stresses on the base metal and heat-affected zone of rail joints welded by the manual shielded metal arc and thermite welding. This research supports the feasibility of welding for rail. The material used in this study is the R-54 rail type, and the procedure used two rail samples of one meter long each, welded using manual shielded metal arc welding and thermite welding. The base metal and heat-affected zone of the welded joints were scanned with neutron ray diffraction. The scan produces a spectrum pattern and reveals the direction of the residual stress along with it. We found the strain value contained in both types of welded joints by looking at the microstrain values, which we obtained using the Bragg equation. The results show that the magnitude and direction of the residual stress produced by manual shielded metal arc welding and thermite welding are not the same. Thermite welding produces lower residual stress (lower crack susceptibility) than manual shielded metal arc welding. The melt's freezing starts from the edge to the center of the weld to create random residual stresses. The residual stress results of both the manual shielded metal arc welding and thermite welding are still below the yield strength of the base metal.

scholarly journals The influence of manual metal arc multiple repair welding of long operated waterwall on the structure and hardness of the heat affected zone of welded joints

2017 ◽  
Vol 62 (1) ◽  
pp. 327-333 ◽  
Author(s):  
J. Pikuła ◽  
M. Łomozik ◽  
T. Pfeifer
Keyword(s):  
Heat Affected Zone ◽  
Welded Joints ◽  
Arc Welding ◽  
Power Plants ◽  
Welded Joint ◽  
Weld Bead ◽  
Boiler Steel ◽  
Metallographic Examination ◽  
Metal Arc Welding ◽  
High Degree

Abstract Welded installations failures of power plants, which are often result from a high degree of wear, requires suitable repairs. In the case of cracks formed in the weld bead of waterwall, weld bead is removed and new welded joint is prepared. However, it is associated with consecutive thermal cycles, which affect properties of heat affected zone of welded joint. This study presents the influence of multiple manual metal arc welding associated with repair activities of long operated waterwall of boiler steel on properties of repair welded joints. The work contains the results of macro and microscopic metallographic examination as well as the results of hardness measurements.

scholarly journals Microstructure and Corrosion Resistance to H2S in the Welded Joints of X80 Pipeline Steel

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1325 ◽  
Author(s):  
Jian-Bao Wang ◽  
Guang-Chun Xiao ◽  
Wei Zhao ◽  
Bing-Rong Zhang ◽  
Wei-Feng Rao
Keyword(s):  
Corrosion Resistance ◽  
Heat Affected Zone ◽  
Welded Joints ◽  
Electrochemical Impedance ◽  
Pipeline Steel ◽  
Electrochemical Corrosion ◽  
Open Circuit ◽  
Coarse Grained ◽  
Granular Bainite ◽  
X80 Pipeline Steel

The microstructure and corrosion resistance in H2S environments for various zones of X80 pipeline steel submerged arc welded joints were studied. The main microstructures in the base metal (BM), welded metal (WM), coarse-grained heat-affected zone (CGHAZ), and fine-grained heat-affected zone (FGHAZ) were mainly polygonal ferrite and granular bainite; acicular ferrite with fine grains; granular bainite, ferrite, and martensite/austenite constituents, respectively. The corrosion behavior differences resulted from the microstructure gradients. The results of the micro-morphologies of the corrosion product films and the electrochemical corrosion characteristics in H2S environments, including open circuit potential and electrochemical impedance spectroscopy, showed that the order of corrosion resistance was FGHAZ > BM > WM > CGHAZ.

Evaluation of UOE and Spiral-Welded Line Pipe for Strain Based Designs

2010 ◽  
Author(s):  
Yankui Bian ◽  
Christopher Penniston ◽  
Laurie Collins ◽  
Robert Mackenzie
Keyword(s):  
Heat Affected Zone ◽  
Work Hardening ◽  
Good Work ◽  
Aging Effects ◽  
Pipe Axis ◽  
Line Pipe ◽  
Advantages And Disadvantages ◽  
Minimum Requirements ◽  
Girth Welds ◽  
Welding Processes

Strain-based designs for Arctic pipelines place stringent demands on properties of the pipe body as well as the girth weld and associated heat affected zone. The pipe body must demonstrate good work hardening behavior in addition to satisfactory strength and toughness properties. Girth welds are required to overmatch the strength of the pipe body; both the weld and heat affected zone must also provide good toughness. In this study, X80 line pipe produced using the UOE and spiral welding processes were compared. The UOE process provides some degree of work hardening resulting from cold expansion. This extra hardening renders the UOE pipe more responsive than the spiral pipe to aging effects associated with pipe coating. However, the UOE pipe has an advantage in balancing LPA (longitudinal to pipe axis) and TPA (transverse to pipe axis) strengths. Greater strengths in the TPA orientation afford the capacity to meet specified minimum requirements of the pipe grade and lower strengths in the LPA orientation facilitate overmatching by girth welds. The two types of line pipe offer both advantages and disadvantages for strain-based designs. It must be emphasized that good work hardening characteristics can be maintained in the UOE pipe when the coating process involves a low temperature, which is an objective of modern coating technologies. It was also observed that aging effects did not affect toughness properties significantly.

FE Simulation of Cold Cracking Susceptibility in X70 Structural Steel Welded Joints

2011 ◽  
Author(s):  
Vigdis Olden ◽  
Odd Magne Akselsen
Keyword(s):  
Hydrogen Embrittlement ◽  
Yield Strength ◽  
Structural Steel ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Welded Joints ◽  
Fe Simulation ◽  
Coarse Grained ◽  
Best Fitting ◽  
Low Sensitivity

Fracture mechanics SENT testing and FE simulation to establish hydrogen influenced cohesive parameters for X70 structural steel welded joints have been performed. Base metal and weld simulated coarse grained heat affected zone have been included in the study. The base metal did not fail at net section stresses lower than 1.29 times the yield strength and reveals low sensitivity to hydrogen embrittlement. The weld simulated coarse grained heat affected zone was prone to fracture at stresses above 64% of the yield strength, which indicates hydrogen embrittlement susceptibility. The cohesive parameters best fitting the experiments are δc = 0.3 mm and σc = 1700 MPa (3.5·σy) for the base metal and δc = 0.3 mm and σc = 2100 MPa (2.6·σy) for the coarse grained heat affected zone.

scholarly journals On Mechanical Properties of Welded Joint in Novel High-Mn Cryogenic Steel in Terms of Microstructural Evolution and Solute Segregation

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 478
Author(s):  
Jia-Kuan Ren ◽  
Qi-Yuan Chen ◽  
Jun Chen ◽  
Zhen-Yu Liu
Keyword(s):  
Microstructural Evolution ◽  
Welded Joint ◽  
Solute Segregation ◽  
Coarse Grained ◽  
Shielded Metal Arc Welding ◽  
Metal Arc Welding ◽  
Long Time ◽  
Segregation Band ◽  
Lng Tank ◽  
Cryogenic Steel

There is a growing demand for high-manganese wide heavy steel plate with excellent welding performance for liquefied natural gas (LNG) tank building. However, studies on welding of high-Mn austenitic steel have mainly focused on the applications of automotive industry for a long time. In the present work, a high-Mn cryogenic steel was welded by multi-pass Shielded Metal Arc Welding (SMAW), and the microstructural evolution, solute segregation and its effect on the properties of welded joint (WJ) were studied. The yield strength, tensile strength and elongation of the WJ reached 804 MPa, 1027 MPa and 11.2% at −196 °C, respectively. The elongation of WJ was reduced with respect to the BM due to the poorer strain hardening capacity of weld metal (WM) at −196 °C. The WM and coarse-grained heat affected zone (CGHAZ) had the lowest cryogenic impact absorbed energy of ~55 J (at −196 °C). The inhibited twin formation caused by the higher critical resolved shear twinning stress ( τ T ) in the C-Mn-Si segregation band, the inhomogeneous microstructure caused by solute segregation, and the hardened austenite matrix deteriorated the plastic deformation capacity, finally resulting in the decreased cryogenic impact toughness of the CGHAZ. To summarize, the cryogenic toughness and tensile properties of the WJ meet the requirements for LNG tank building.

Application of Multiple Methods of NDT for the Evaluation of Welded Joints in a Steel Bridge ASTM-A-588

2019 ◽  
Vol 287 ◽  
pp. 8-12
Author(s):  
Héctor C. Terán ◽  
Oscar Arteaga ◽  
F.S. Alcocer ◽  
Richard R. Navas ◽  
Stalin P. Mena ◽  
...  
Keyword(s):  
Welded Joints ◽  
Arc Welding ◽  
Base Material ◽  
Steel Bridge ◽  
Shielded Metal Arc Welding ◽  
Destructive Testing ◽  
Final State ◽  
Metal Arc Welding ◽  
Flux Cored Arc Welding ◽  
Non Destructive

This work is based on making a comparison of different inspection methods of non-destructive testing (NDT), to detect porosity, bite, undercut, splash, overlap, slag, concavity, lack of fusion and damage to base material, in welds of shielded metal arc welding (SMAW) and flux-cored arc welding (FCAW), made on a steel bridge ASTM-A-588. The main application of non-destructive tests is to evaluate the final state of a welded joint in critical points, in addition the fundamental objective is to ensure that the established acceptance and rejection criteria are met rigorously. For which non-destructive techniques are analyzed, such as the visual testing of welding on the beams of a bridge of length 35000 mm, subsequently, tests of inspection by liquid penetrant were used, based on the AWS D1.5 standard to confirm the failures in welded joints in ABA webs, an ultrasonic is also carried out using an SIUI CTS 602 equipment, finally to issue an acceptance and rejection criterion as determined by ASTM E165 and ASTM E2544-09.

Influence of Steel Chemistry and Field Girth Welding Procedure on Performance of API X70 Line Pipe Steels

2020 ◽  
Author(s):  
Mohsen Mohammadijoo ◽  
Laurie Collins ◽  
Muhammad Rashid ◽  
Muhammad Arafin
Keyword(s):  
Welding Process ◽  
Strain Analysis ◽  
Image Correlation ◽  
Shielded Metal Arc Welding ◽  
Line Pipe ◽  
Factors Affecting ◽  
Metal Arc Welding ◽  
Girth Welding ◽  
Welding Procedure ◽  
Haz Toughness

Abstract Owing to recent concerns regarding pipeline field girth weld performance, particularly heat affected zone (HAZ) softening and toughness, EVRAZ North America has initiated a research program to evaluate the response of API grade line pipe to the current field girth welding practices. In particular, this study aims to elucidate the role of steel alloy design as well as the welding procedure on field girth weld and HAZ properties. This understanding is critical to balance the detrimental effects of HAZ softening on the overall joint strength against factors affecting HAZ toughness. A selection of several different steels with different levels of alloying elements, Ceq and Pcm have been subjected to welding trials to assess the effects of chemistry on joint performance. Furthermore, an analysis on the effect of welding process parameters on the joint properties has been made. The welds, fabricated via a manual shielded metal arc welding (M-SMAW) process, were evaluated in terms of toughness, local vs global strain distribution during tensile testing using digital image correlation (DIC) technique, and hardness contour mapping of the weld and HAZ regions. The results explicitly show that the extent of HAZ softening decreased as the amount of Mo, Mn, Ti/N and Ceq increased. However, this alloying addition resulted in a detrimental effect on the HAZ toughness, particularly towards the cap and fill passes. The HAZ softening increased as the inter-pass temperature and the welding heat input increased. In addition, the strain analysis confirmed the weld passes towards the root/hot passes are more prone to HAZ softening compared with the upper cap and fill passes.

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