scholarly journals Effect of the Interpass Temperature on Simulated Heat-Affected Zone of Gas Metal Arc Welded API 5L X70 Pipe Joint

Author(s):  
Paulo Henrique Grossi Dornelas ◽  
João da Cruz Payão Filho ◽  
Victor Hugo Pereira Moraes e Oliveira ◽  
Diogo de Oliveira Moraes ◽  
Petrônio Zumpano Júnior

Abstract Welding costs associated with the laying of pipes for deepwater oil and gas extraction can be reduced using high interpass temperatures (ITs). However, a high IT can decrease the mechanical properties of the heat-affected zone (HAZ) of welded joints. With the use of high strength-toughness stees, this decrease may be an acceptable trade-off. Therefore, it is necessary to evaluate the influence of high ITs on the HAZ. The influence of the IT on the coarse grain HAZ (CGHAZ) and intercritically reheated coarse-grain HAZ (ICCGHAZ) of an API 5L X70 pipe joint welded by gas metal arc welding was investigated. The welding was numerically simulated using finite element method software. The microstructure of the HAZ was predicted using thermodynamic simulation software. The CGHAZ and ICCGHAZ were also physically simulated and evaluated via optical microscopy and scanning electron microscopy, dilatometry, and Vickers microhardness and Charpy V-notch (CVN) impact tests. The increase in IT led to a decrease in CGHAZ microhardness, but did not affect the ICCGHAZ. The CVN energies obtained for all ITs (CGHAZ and ICCGHAZ) were higher than that set by the DNVGL-ST-F101 standard (50 J). These results show that increasing the IT is an interesting and effective method to reduce welding costs. In addition, thermodynamic simulation proved to be a valid method for predicting the phases in the HAZ of API 5L X70 pipe welded joints.

2019 ◽  
Vol 269 ◽  
pp. 06003
Author(s):  
Herry Oktadinata ◽  
Winarto Winarto

Various welding methods are widely applied in large fabrication of high strength steel. However, commonly the problem occurs where a coarse grain is formed near fusion zone causing reduce the impact toughness due to the weld joint become brittle. Ductility and toughness in a coarse grain heat affected zone (CGHAZ) is low due to the formation of coarsening grain size. The objective of this research is to investigate the microstructure evolution, impact toughness and fracture appearance at sub-zero temperatures of the high strength steel arc welded. The steel that used in this experiment is a HY-80 steel welded by gas metal arc welding (GMAW) with a mixture of argon and carbon dioxide (90%Ar and 10%CO2) and ER100S solid wire. Microstructure observation and Charpy V-notch (CVN) tests were performed on the weld joint which consist of base metal (BM), heat affected zone (HAZ), and weld metal (WM). The CVN tests on the HY-80 steel plate at various temperatures (20, -20, -60 and -80 °C) show impact toughness decrease when the test temperature decrease. The CVN tests on the HY-80 weld joint at a temperature of 80 °C show the lowest impact toughness was measured at WM (61 J) and followed fusion line-FL (101 J) with brittle fracture appearance.


2010 ◽  
Vol 652 ◽  
pp. 275-278
Author(s):  
Ran Wei ◽  
Lin Cheng ◽  
Kai Ming Wu

The weldability of a 700 MPa grade low carbon Ti-containing microalloyed bainitic steel produced by compact strip production (CSP) has been investigated by gas metal arc welding. Microstructural features of the welded joint of the investigated steel have been investigated utilizing optical and scanning electron microscopy (SEM). The microstructures in the heat affected zone (HAZ) consist of a predominantly bainitic ferrite and a proportion of acicular ferrite which formed on Ti-oxide and/or nitride particles. The acicular ferrite formed earlier effectively partitions prior austenite grains into smaller separate regions. The bainite transformed at lower temperatures is thus restricted in the smaller regions so that fine-grained mixed microstructures are obtained. The superior toughness of the weld joint of the investigated steel is attributed to the prior formation of acicular ferrite in the heat-affected zone.


2015 ◽  
Vol 812 ◽  
pp. 29-34 ◽  
Author(s):  
Ádám Dobosy ◽  
János Lukács

The objective of this article is to present the first results of our research work. In order to determination and comparison of the fatigue resistance, high cycle fatigue tests (HCF) were performed on RUUKKI OPTIM S690QL quenched and tempered high strength steel. In parallel these; welded joints were made on the same steel using gas metal arc welding (GMAW, MIG/MAG) to preparation of the cyclic investigations of the welded joints. In the article, the performance of the welding experiments will be presented; along with the results of the HCF tests executed on the base material and its welded joints. Furthermore, our results will be compared with different literary data.


Author(s):  
Xiaodong He ◽  
Yangqin Liu ◽  
Lixia Zhu ◽  
Ke Tong ◽  
Xiaodong Shao

The X80 girth welds were produced by solid-wire gas metal arc welding (GMAW) and shield metal arc welding (SMAW) using two welding consumables respectively, which contained different mass fraction of C, Mo and Ni. The tensile properties, notch toughness, hardness, and microstructures of welded joints were evaluated. The results indicate that high strength and good toughness of welded joints can be achieved. But the tensile properties of all weld metal of GMAW and SMAW process were evidently different because of the difference of mass fraction of C, Mo, Ni. The strength reduced slightly in softening zone of HAZ. Using welding consumable which contain higher Mo additions, the microstructure in weld seam and fusion zones were IAF+GB and GB+M respectively. Furthermore, the mechanical properties of X80 pipeline welded by single wire welding and double wire welding respectively have been compared. The double wire welds exhibited lower yield strength but higher toughness compared to the corresponding single wire welds.


2014 ◽  
Vol 936 ◽  
pp. 1747-1753
Author(s):  
Xiao Dong He ◽  
Ke Tong ◽  
Ming Hua Liang ◽  
Li Xia Zhu ◽  
Wei Ping Lin

The X80 girth welds were produced by solid-wire gas metal arc welding (GMAW) and shield metal arc welding (SMAW) using two welding consumables respectively, which contained different mass fraction of C, Mo and Ni. The tensile properties, notch toughness, hardness, and microstructures of welded joints were evaluated. The results indicate that high strength and good toughness of welded joints can be achieved. But the tensile properties of all weld metal of GMAW and SMAW process were evidently different because of the difference of mass fraction of C, Mo, Ni. The strength reduced slightly in softening zone of HAZ. Using welding consumable which contain higher Mo additions, the microstructure in filler weld and fusion zones were IAF+GB and GB+M respectively. Furthermore, the mechanical properties of X80 pipeline welded by single wire welding and double wire welding respectively have been compared. The double wire welds exhibited lower yield strength but higher toughness compared to the corresponding single wire welds.


Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1077 ◽  
Author(s):  
Seungmin Shin ◽  
Sehun Rhee

In this study, lap joint experiments were conducted using galvanized high-strength steel, SGAFH 590 FB 2.3 mmt, which was applied to automotive chassis components in the gas metal arc welding (GMAW) process. Zinc residues were confirmed using a semi-quantitative energy dispersive X-ray spectroscopy (EDS) analysis of the porosity in the weld. In addition, a tensile shear test was performed to evaluate the weldability. Furthermore, the effect of porosity defects, such as blowholes and pits generated in the weld, on the tensile shear strength was experimentally verified by comparing the porosity at the weld section of the tensile test specimen with that measured through radiographic testing.


2017 ◽  
Vol 62 (1) ◽  
pp. 327-333 ◽  
Author(s):  
J. Pikuła ◽  
M. Łomozik ◽  
T. Pfeifer

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.


Author(s):  
Emre Korkmaz ◽  
Cemal Meran

In this study, the effect of gas metal arc welding on the mechanical and microstructure properties of hot-rolled XPF800 steel newly produced by TATA Steel has been investigated. This steel finds its role in the automotive industry as chassis and seating applications. The microstructure transformation during gas metal arc welding has been analyzed using scanning electron microscope, optical microscope, and energy dispersive X-ray spectrometry. Tensile, Charpy impact, and microhardness tests have been implemented to determine the mechanical properties of welded samples. Acceptable welded joints have been obtained using heat input in the range of 0.28–0.46 kJ/mm. It has been found that the base metal hardness of the welded sample is 320 HV0.1. On account of the heat-affected zone softening, the intercritical heat-affected zone hardness values have diminished ∼20% compared to base metal.


Author(s):  
Yoshiyuki Matsuhiro ◽  
Noritake Oguchi ◽  
Toshio Kurumura ◽  
Masahiko Hamada ◽  
Nobuaki Takahashi ◽  
...  

The construction of the first L555(X80) pipeline in Japan was completed in autumn, 2011.In this paper, the overview of the design consideration of the line, technical points for linepipe material and for girth welds are presented. In recent years the use of high strength linepipe has substantially reduced the cost of pipeline installation for the transportation of natural gas. The grades up to L555(X80) have been used worldwide and higher ones, L690(X100) and L830(X120), e.g., are being studied intensively. In the areas with possible ground movement, the active seismic regions, e.g., pipeline is designed to tolerate the anticipated deformation in longitudinal direction. In Japan, where seismic events including liquefaction are not infrequent, the codes for pipeline are generally for the grades up to L450(X65). Tokyo Gas Co. had extensively investigated technical issues for L555(X80) in the region described above and performed many experiments including full-scale burst test, full-scale bending test, FE analysis on the girth weld, etc., when the company concluded the said grade as applicable and decided project-specific requirements for linepipe material and for girth weld. Sumitomo Metals, in charge of pipe manufacturing, to fulfill these requirements, especially the requirement of round-house type stress-strain (S-S) curve to be maintained after being heated by coating operation, which is critical to avoid the concentration of longitudinal deformation, developed and applied specially designed chemical composition and optimized TMCP (Thermo-Machanical Control Process) and supplied linepipe (24″OD,14.5∼18.9mmWT) with sufficient quality. It had also developed and supplied induction bends needed with the same grade. Girth welds were conducted by Sumitomo Metal Pipeline and Piping, Ltd and mechanized GMAW (Gas Metal Arc Welding) was selected to achieve the special requirements, i.e., the strength of weld metal to completely overmatch the pipe avoiding the concentration of longitudinal strain to the girth weld, and the hardness to be max.300HV10 avoiding HSC (Hydrogen Stress Cracking) on this portion. Both of RT (Radiographic Test) and UT (Ultrasonic Test) were carried out to all the girth welds. These were by JIS (Japan Industrial Standards) and the project-specific requirements.


Sign in / Sign up

Export Citation Format

Share Document