The Effects on Process Performance of Reducing the Pressure From 36 to 1Bar in Hyperbaric MIG Welding

Author(s):  
Hans Fostervoll ◽  
Neil Woodward ◽  
Odd M. Akselsen

Technology for remotely controlled (diverless) repair welding of subsea pipelines from 170 to 1000m water depth is being developed by StatoilHydro. The repair technology is based on a sleeve concept combined with MIG welding and the development is currently nearing completion. Technology for diver-assisted remotely controlled welding down to about 200m has been used in the North Sea for about twenty years. In order to reduce the use of divers, the deep water diverless technology is also being considered for use in shallow waters. The present work has been performed to investigate whether the deepwater welding procedure may also be used in shallow waters, and which modifications for the lower pressure conditions need to be made. Test welding has been performed in the pressure range from 36 to 1bar corresponding to 350 to 0m sea water depth to study the effect of ambient pressure upon the welding process behaviour and weld bead appearance and geometry. For the 12 o’clock welding position tested, welding parameters developed for deep water conditions also worked well for shallow water conditions down to about 2bar. It was also evident that the electrode polarity, which is negative for the deep water procedure, had to be changed to electrode positive for the lowest pressures, which coincides with conventional 1-atm MIG welding. Mechanical property testing and microstructure examinations revealed satisfactory results using the modified welding procedure.

2013 ◽  
Vol 455 ◽  
pp. 425-430 ◽  
Author(s):  
Xue Wu Wang ◽  
Shang Yong Yang

Intelligent procedure expert system was developed to select appropriate GTAW procedure in this paper. First, the function design and implementation methods of the welding procedure expert system were introduced. The expert system can present the welding procedure card, multimedia display of welding process, and output function to makes the data sharing more convenient. Then, the database design of the welding procedure expert system based on C/S mode was presented where the expert knowledge was stored. At last, the neural network model was established to realize procedure selection based on the neural network learning ability and the welding case from the database. With the BPNN model, the welding parameters can be obtained based on the input welding conditions.


Author(s):  
Yu-Ping Yang ◽  
Zhenning Cao ◽  
Jerry Gould ◽  
Tom McGaughy ◽  
Jon Jennings

A Microsoft Excel-based screening tool was developed to allow an engineer with weld process knowledge to predict cooling rate and hardness during welding procedure qualifications to screen a combination of materials and welding process parameters quickly to meet requirements of fabrication and design codes. The material properties for commonly used pipeline steels have been built into a database coupled with the screening tool. The Excel-based tool includes a physics-based laser and arc welding solution which was developed based on Rosenthal’s mathematical equations for a point heat source to predict thermal cycles by inputting welding parameters. A reflecting heat source scheme was adapted to model the boundary conditions and plate thickness effect on cooling rate. The Excel-based tool also includes a microstructure model which was developed based on the Ashby model. The microstructure model can be used to predict the distributions of individual phases such as ferrite, bainite, and martensite along with a hardness map across the weld and heat-affected-zone (HAZ) regions by integrating with the thermal model.


Author(s):  
Hiroyuki Nagayama ◽  
Masahiko Hamada ◽  
Mark F. Mruczek ◽  
Mark Vickers ◽  
Nobuyuki Hisamune ◽  
...  

Ultra-high strength seamless pipes of X90 and X100 grades have been developed for deepwater or ultra-deepwater applications. Girth welding procedure specifications (WPSs) should be developed for the ultra-high strength pipes. However, there is little information for double jointing welding procedure by using submerged arc welding process for high strength line pipes. This paper describes mechanical test results of submerged arc welding (SAW) and gas shielded flux cored arc welding (GSFCAW) trials with various welding consumables procured from commercial markets. Welds were then made with typical welding parameters for riser productions using high strength X90 seamless pipes. The submerged arc weld metal strength could increase by increasing alloy elements in weld metal. The weld metal with CE (IIW) value of 0.74 mass% achieved fully overmatching for the X90 pipe. The weld metal yield strength (0.2% offset) was 694 MPa, and the ultimate tensile strength was 833 MPa. It was also confirmed that the reduction of boron in weld metal can improve low temperature toughness of high strength weld metal. Furthermore, it was confirmed that the HAZ has excellent mechanical properties and toughness for riser applications. In this study GSFCAW procedures were also developed. GSFCAW can be used for joining pipe and connector material for riser production welding. The weld metal with a CE (IIW) value of 0.54 mass% could meet the required strength level for X90-grade pipe as specified in ISO 3183. Cross weld tensile testing showed that fractures were achieved in the base metal. Good Charpy impact properties in weld metal and HAZ were also confirmed.


2019 ◽  
Vol 269 ◽  
pp. 06001 ◽  
Author(s):  
Dahia Andud ◽  
Muhd Faiz Mat ◽  
Yupiter HP Manurung ◽  
Salina Saidin ◽  
Noridzwan Nordin ◽  
...  

This research deals with a method and procedure for enhancing the structural life of the commonly used steel structure in oil and gas industries HSLA S460G2+M with a thickness of 10 mm. The type of joint and welding process is T-joint with transverse and longitudinal attachment welded using semi-automated GMAW. Filler wire ER80S-Ni1 and mixed shielding gas (80% Ar / 20% CO2) is used as material consumables. At first, the best suitable welding parameters are comprehensively investigated, prepared, tested and qualified according to welding procedure specification (WPS) qualification requirements. Further, the weld toe is treated by using HFMI/PIT with a frequency of 90Hz, 2 mm pin radius and air pressure of 6 bars. In accordance with the recommendation of the International Welding Institute (IIW), fatigue test is conducted using constant amplitude loading with the stress ratio of 0.1 and loading stresses from 55% to 75% of the yield strength of the material. Finally, the results of the fatigue experimental are compared with the fatigue recommendation of as-welded and HFMI/PIT of IIW as well as the untreated raw material. As a conclusion, it is observed that the fatigue life is increased up to 300% compared to IIW and 70% to as-welded. It is also obvious that treated transverse T-joint shows significant improvement than the longitudinal attachment.


2017 ◽  
Vol 885 ◽  
pp. 80-85 ◽  
Author(s):  
Eszter Kalácska ◽  
Kornél Májlinger ◽  
Enikő Réka Fábián ◽  
Pasquale Russo Spena

The need for steel materials with increasing strength is constantly growing. The main application of such advanced high strength steels (AHSS) is the automobile industry, therefore the welding process of different types of AHSSs in dissimilar welding joint was investigated. To simulate the mass production of thin steel sheet constructions (such as car bodies) automated metal inert gas (MIG) welding process was used to weld the TWIP (twinning induced plasticity) and TRIP (transformation induced plasticity) steel sheets together. The welding parameters were successfully optimized for butt welded joints. The joints were investigated by visual examination, tensile testing, quantitative metallography and hardness measurements. The TRIP steel side of the joints showed increased microhardness up to (450-500 HV0.1) through increased fraction of bainite and martensite. Macroscopically the tensile specimen showed ductile behaviour, they broke in the austenitic weld material.


2011 ◽  
Vol 264-265 ◽  
pp. 1270-1280
Author(s):  
Marco Brandizzi ◽  
Annunziata Anna Satriano ◽  
Luigi Tricarico

CO2 laser - Metal Inert Gas (MIG) hybrid welding process was investigated in the butt welding of Ti-6Al-4V titanium alloy sheets of 3.0mm in thickness. Using a Design of Experiment (DoE) approach, bead on plate tests were planned with the aim to analyze the effect of laser and laser-MIG welding parameters on the bead shape, hardness profiles in the weld cross section and welding efficiency. Butt welds performed in correspondence of the bead on plate working conditions which assure the complete penetration of the samples, the absence of undercuts and the maximum welding efficiency, confirm the results of the bead on plate tests and highlights the gap bridging ability of the hybrid welding process.


1987 ◽  
Vol 23 (2) ◽  
pp. 201-206 ◽  
Author(s):  
B. B. Reddy ◽  
B. C. Ghosh ◽  
M. D. Reddy

SummaryWater depth at or shortly after planting is critical for the establishment and subsequent tolerance of excess water in rice. A crop transplanted early in the season produced twice as much grain as a later planted crop. A semi-dwarf variety (CR 1018) and a taller variety (CR 1030) performed similarly after early transplanting, but the tall variety performed better when planted late under excess water. Seedling age did not greatly alter the yields when crops were transplanted early, but after late planting 45-day-old seedlings were best.


2008 ◽  
Vol 580-582 ◽  
pp. 251-258
Author(s):  
Jin Seok Oh ◽  
Jong Do Kim ◽  
Jun Ho Kwak ◽  
Ji Young Lee

Welding tasks in shipbuilding create great problems for a manual welder since welding takes place in closed area with associated work environmental problems. This paper addresses the problems involved in the welding robot with control algorithm and system. The control system may similarly be modified as a tracking simulation test. The performance of the control system is assessed through the use of field data. The aim of this paper is to determine feasible parameters for a welding procedure with simulation for seam tracking of welding robot system. The main advantage of tracking simulation is its flexibility in that as the welding parameters are modified at a sufficiently high rate. Tracking simulation showed that the development of robot control algorithms should be performed by simulation, since it saves time, expenses and efforts. This paper will contribute to an increased use of automated welding technology with tracking simulation methods. Also, this paper’s results can be used for the optimization of welding process using simulation method with LabVIEW.


2012 ◽  
Vol 524-527 ◽  
pp. 1423-1428
Author(s):  
Xun Cheng Song ◽  
Xiao Long Xu ◽  
Sha Sha Hu ◽  
Zhi Chuan Guan

Wellbore temperature is significant to well program and safety drilling for deep water drilling operations. On the basis of transient heat transfer mechanisms involved in deep water drilling among wellbore and formation and sea water, wellbore temperature profile, especially near sea bed and sensitivities to drilling fluid circulating duration, inlet temperature, water depth, water temperature, riser insulation and drilling fluid specific heat capacity have been analyzed via this model. Analysis show that deep-water wellbore temperature is much lower than a land well, the temperatures above sea bed normally ranges 10-30°C, and decreases with increased circulating duration; temperature at both outlet and bottom hole decreases drastically with increased water depth, and heat generation must be considered into estimating wellbore temperature profile especially one at bottom hole.


This paper studies the butt welded joint of SUS316L stainless steel. The butt joint is not beveled, has a gap and is welded in one pass by MIG welding process. First, the welding parameters of this weld are determined through calculation and test welding for the butt joint of two plates of 3 mm in thickness. Then these welding parameters are used as input data to calculate and determine the temperature field by two methods: the calculation method based on the theory of heat transfer process and the numerical simulation method of welding processes that relies on SYSWELD software on the basis of the finite element method. The calculation results of the two methods were compared with each other and tested by experiment to show the reliability of calculation and simulation results.


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