scholarly journals OPTIMALISASI KOMPOSISI KANDUNGAN MN PADA FILLER UNTUK MENDAPATKAN KETANGGUHAN DAN KEKERASAN

2012 ◽  
Vol 12 (1) ◽  
pp. 41
Author(s):  
NUR SUBEKI
Keyword(s):  
Weld Metal ◽  
Acicular Ferrite ◽  
High Reliability ◽  
Welding Process ◽  
Welded Steel ◽  
Steel Pipes ◽  
Weld Metals ◽  
Ferrite Structure ◽  
Relationship Of ◽  
Submerged Arc

Submerged Arc Welding (SAW) is a welding process used for fabrication of pipes, for example spiral welded pipes. Thetechnique can be operated automatically and has a high reliability in many various welding applications. Some factorsaffecting the strength of weld metals are heat input, current, and chemical composition of filler, flux, and base metal.The present investigation aims to study microstructure-hardness relationship of submerged arc spiral welded steel pipes. Material used in this experiment was API 5L X-52 and API 5L X-60 for spiral welded steel pipes. Welding was carried out using voltage of 35 volt, welding speed of 13,67 mm/s whereas composition Mn on the flux was varied, 1.7; 1.4; 1.4 with Mo and 1.09. Microstructure and hardness were conducted on base metal, weld metal and heat affected zone (HAZ). Results show that, an increase in composition of Mn could be increases the amount of acicular ferrite structure in weld metal. The hardness and thougness number is increase correlated with increase number of Mn, but for the composition Mn as 1,7, the number of acicular ferrite is decrease, the consequence of hardness number is decrease.

Microstructure Transformation and Mechanical Properties of X80 Large Diameter Thick Wall Induction Heating Bend for Low Temperature Service

2020 ◽  
Author(s):  
Yu Liu ◽  
Zongbin You ◽  
Lijun Yan
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Weld Metal ◽  
Acicular Ferrite ◽  
Base Material ◽  
Welding Process ◽  
Seam Weld ◽  
Bent Pipe ◽  
Low Temperature Toughness ◽  
Submerged Arc

Abstract For the requirement of pipeline station construction project, Grade X80 Longitudinally Submerged Arc Welded (LSAW) induction bend pipe 1422 mm in diameter and wall thickness greater than 25 mm have been developed for pipeline station service applications at −45 °C. The mother pipe of the bends was welded by Ni-Cr-Cu-Mo-Nb-V micro-alloyed Thermo Mechanical Control Process (TMCP) steel plates. After the heat cycle of the bent pipe manufacturing, the microstructure of the base material of the bent pipe consisted of lath bainite ferrite (LBF) and granular bainite (GB). Therefore, it can obtain high strength and excellent low temperature toughness, which can meet the requirements of the project. On the other hand, the welding of the longitudinal seam-welds of the bend mother pipe uses a typical multi-wire two-pass submerged arc welding (SAW) process, which has a large amount of welding heat input. This results in a coarse columnar weld structure with a large amount of fine acicular ferrite so that the seam weld still has a good low temperature impact toughness. However, after the thermal cycling of the bend, the acicular ferrite in the microstructure of the weld metal was greatly reduced, and the grain size was unevenly distributed, which caused the low temperature toughness of the weld metal to deteriorate significantly. In order to solve this problem, the Gleeble3500 thermal simulation test machine was used to test the phase transition critical point Ac3 of the base material and the seam weld metal of the mother pipe. In order to optimize the induction bend process parameters, the influence of heating temperature, cooling rate and tempering temperature on microstructure and mechanical properties were examined. In addition, on the basis of the existing welding process, the welding wire and flux for pipe-making seam-welding were improved, and the pipe-making welding process of the bent mother pipe was improved.

Recommendations for Submerged Arc Spiral Welding With Optimized CTOD Properties

2018 ◽  
Author(s):  
Martin Liebeherr ◽  
Özlem E. Güngör ◽  
Nuria Sanchez ◽  
Hervé Luccioni ◽  
Nenad Ilic
Keyword(s):  
Weld Metal ◽  
Base Material ◽  
Welding Process ◽  
Experimental Program ◽  
Welding Parameters ◽  
Pipe Production ◽  
Filler Wire ◽  
Crack Tip Opening Displacement ◽  
Wide Range ◽  
Submerged Arc

Many pipe mills may not be familiar with a Crack Tip Opening Displacement (CTOD) requirement on the pipe seam weld, nor will they find easily relevant information in open literature. Influencing — and certainly not independent — factors are: welding parameters, base material and consumable selection. Out of these, the welding parameters such as heat input and cooling rate cannot be varied over a wide range during the pipe production, which means that the leverage is rather limited at the given welding process. The properties of the heat affected zone will be mainly affected by the base material, while the properties of the weld metal will be affected by both, base material and filler wire selection. In particular with respect to the weld metal properties it will be difficult to obtain general quantitative information. For example, a welding consumable supplier will readily provide the properties of the filler wires but would be unable to predict the changes caused by the dilution from any base material in the weld pool and specific welding procedures that may have been used. To support the pipe mills in the selection of the consumables for submerged arc welding, an experimental program was launched with the aim to provide recommendations on how to optimize CTOD toughness of the spiral weld seam. For this, a large number of welds were produced on 20 mm thick X70 coil samples, with eight different filler wire combinations, using a 2-wire (tandem) set-up for both the inside and outside weld. Welding parameters were kept constant. The welding program was applied to two different X70 steels to determine a potential influence of the micro-alloying elements, particularly Nb. The results show clearly that a careful consumable selection is required for obtaining acceptable CTOD toughness in the weld metal. Ni-Mo and Ti-B additions to the weld metal are found to be beneficial with both steel concepts. Mo addition alone both to the ID and OD welds was clearly not a suitable selection.

Minimization of Residual Stresses in Submerged Arc Welding Process of Oil and Gas Steel Pipes by Committee Machine

2014 ◽  
Vol 564 ◽  
pp. 519-524
Author(s):  
Seyed Jafar Golestaneh ◽  
N. Ismail ◽  
M.K.A.M. Ariffin ◽  
S.H. Tang ◽  
Mohammad Reza Forouzan ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Arc Welding ◽  
Oil And Gas ◽  
Traditional Approach ◽  
Welding Process ◽  
Submerged Arc Welding ◽  
Committee Machine ◽  
Steel Pipes ◽  
Input Variables ◽  
Submerged Arc

Submerged arc welding (SAW) is a well-known method to weld seam in manufacturing of large diameters steel pipes in oil and gas industry. The main subject of SAW design is selection of the optimum combination of input variables for achieving the desired output variables of weld. Input variables include voltage, amperage and speed of welding and output variables include residual stresses due to welding. On the other hand, main target in multi response optimization (MRO) problem is to find input variables values to achieve to desired output variables. Current study is a combination and modification of some works of authors in MRO and SAW subjects. This study utilizes an experiment design according to Taguchi arrays. Also a committee machine (CM) modeling the problem by CM using two approaches. The first CM consists eight experts with traditional approach in computation and second CM includes elite experts. Genetic algorithm was applied to find CM weights and desired responses. Results show that proposed approach in CM has a smaller root mean squire error (RMSE) than traditional approach. The validation of CM model is done by comparison of results with simulation of SAW process and residual stresses in a finite element environment. Finally, the results show few differences between the real case responses and the proposed algorithm responses.

Investigation on Deposited Metal Properties of Homemade Nickel and Nickel-Free Electrodes and Fluxes for Submerged Arc Welding of SA-508 Gr.3 Cl.1

2017 ◽  
Author(s):  
Le Mei ◽  
Junbao Zhang ◽  
Yifeng Huang ◽  
Yan Yu ◽  
Yong Jiang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Weld Metal ◽  
Arc Welding ◽  
Proton Irradiation ◽  
Submerged Arc Welding ◽  
Impact Property ◽  
Welding Material ◽  
Weld Metals ◽  
Metal Properties ◽  
Submerged Arc

Up to now, two kinds of filler metal with or without nickel element for submerged arc welding have been largely used in the reactor pressure vessel (RPV) manufacturing. In order to study the effect of nickel element on weld metal properties of SA-508 Gr.3 Cl.1, submerged arc welding material with nickel (AWS classification F8P4-EGN-F2N, F2 for short) and welding material without nickel (F8P4-EA3N-A3N, A3 for short) were used; and conventional mechanical properties, low-cycle fatigue test, and proton irradiation analysis of the two weld metals were studied. Results show that the mechanical properties of the two different weld metals are similar, except that the Charpy V-notch impact property of the weld metal with nickel is better than that without nickel; the micro-structures of F2 and A3 weld metals are both composed of ferrite base and granular bainite, but the columnar grain size of F2 weld metal is smaller relatively, which results in better impact property. In addition, the irradiated A3 weld metal has fewer dislocation loops than the irradiated F2 weld metal after the same proton irradiation dose; the irradiated weld metals both have higher micro-Vickers hardness than before.

The role of addition of Ni on the microstructure and mechanical behaviour of C-Mn weld metals

Exacta ◽  
2008 ◽  
Vol 5 (1) ◽  
Author(s):  
Vicente Braz da Trindade ◽  
João Da Cruz Payão ◽  
Luís Felile Guimarães Souza ◽  
Ronaldo Da Rocha Paranhos
Keyword(s):  
Heat Treatment ◽  
Weld Metal ◽  
Nickel Content ◽  
Stress Relief ◽  
Impact Testing ◽  
Microstructural Refinement ◽  
Weld Metals ◽  
The Impact ◽  
Submerged Arc

The aim in this work is to study the influence of nickel content (as-welded state and after stress relief heat treatment) on the microstructure and toughness of CMn weld metals obtained with submerged arc welding. The nickel content vary between 0.50 wt.% and 3.11 wt.%. The microstructures were observed using optical microscopy (OM) and scanning electron microscopy (SEM). The toughness was evaluated by Charpy-V impact testing in samples cut transversally to the weld bead. The impact energy showed that nickel content up to 1 wt.% improves the toughness due to the increase of the acicular ferrite (AF) content and microstructural refinement. On the other hand, higher nickel contents have a deleterious effect on the toughness due to the presence of the microconstituent martensite-austenite (M-A) in the weld metal. The stress relief heat treatment did not improve too much the weld metal toughness, even the M-A suffering decomposition (ferrite+carbide). This may be explained by the precipitation of carbides along the boundaries of the ferrite.

The Influence of Diffusible Hydrogen in Weld Metal and Moisture Content Levels in Flux Related With Weld Metal Mechanical Properties in Submerged Arc Welding Process for Line Pipe Manufacturing

2015 ◽  
Author(s):  
Gautam Chauhan ◽  
Piyush Thakor ◽  
Satyanarayana Samavedam ◽  
Ramakrishnan Mannarsamy ◽  
Ashif Sheikh ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Moisture Content ◽  
Weld Metal ◽  
Hydrogen Content ◽  
Welding Process ◽  
Diffusible Hydrogen ◽  
Line Pipe ◽  
Arc Welding Process ◽  
Submerged Arc ◽  
Pipe Manufacturing

The mechanical properties of welding material is correlative with the diffusible hydrogen content in weld metal and level of moisture content in flux. Minitab16program to predict mechanical properties correlated to diffusible hydrogen content in weld metal and level of moisture content in flux, such as yield strength, tensile strength, elongation and average Charpy impact toughness of welding material is established by using submerged arc welding process in line pipe manufacturing. The present paper aims to experiment and investigate the line pipe SAW Flux used for offshore/onshore applications. Flux moisture content has been studied under Karl Fischer Coulometer method. Subsequently, flux was then used to make weld to analysis for ‘diffusible hydrogen content in weld metal’ through mercury displacement method. This detailed study envisages and explains the correlations between the mechanical properties and micro structures of weldments. Evaluating the variance of moisture level in flux and diffusible hydrogen content in weld metal proves the advantage of restricting the moisture content along with good practices to accomplish better weld quality.

scholarly journals Microstructure features and formation mechanism in a newly developed electroslag welding

2021 ◽  
Author(s):  
Tomonori Kakizaki ◽  
Shodai Koga ◽  
Hajime Yamamoto ◽  
Yoshiki Mikami ◽  
Kazuhiro Ito ◽  
...  
Keyword(s):  
Low Temperature ◽  
Weld Metal ◽  
Heat Input ◽  
Acicular Ferrite ◽  
Charpy Impact ◽  
Electroslag Welding ◽  
Weld Metals ◽  
Columnar Grains ◽  
Cooling Speed ◽  
Low Temperature Toughness

AbstractElectroslag welding (ESW) is known to show higher heat input than electrogas welding (EGW), resulting in poor low-temperature toughness. However, a newly developed ESW (dev. ESW) method using low-resistivity slag bath exhibited excellent low-temperature toughness as a result of lower effective heat input than conventional EGW, as demonstrated by the faster cooling rates measured in weld metals and estimated using finite element method analyses. This led to much shallower molten pool in the dev. ESW, resulting in much finer columnar grains and thinner centerline axial grains. High cooling speed in the dev. ESW method appeared to contribute to increased acicular ferrite proportion. The uniform microstructure with large acicular ferrite proportion and small number of inclusions in the weld metal permitted the dev. ESW weld metal to possess little variation in Charpy impact energy across the center of weld metal.

TMF Influence on Weld Structure at the Welding of 12X18H9T

2018 ◽  
Vol 927 ◽  
pp. 1-5 ◽  
Author(s):  
Alexander D. Razmyshlyaev ◽  
Marina V. Ahieieva ◽  
Elena V. Lavrova
Keyword(s):  
Magnetic Field ◽  
Weld Metal ◽  
Arc Welding ◽  
Welding Process ◽  
Metal Structure ◽  
Transverse Magnetic ◽  
Submerged Arc Welding ◽  
Structural Components ◽  
Weld Structure ◽  
Submerged Arc

The transverse magnetic field (TMF) use allows to obtain follow effects: increasing the electrode melting coefficient, reducing the base metal penetration depth and grinding the weld metal structural components. The paper analyzed the existing literature data about the TMF influence on the refinement of the weld metal structure. It is experimentally shown that the alternating TMF influence of 6 Hz frequency reduces the grain size of weld metal is almost twice in comparison with the welding process without the TMF influence at submerged arc welding of plates of austenitic steel type 12X18H9T (X10CrNiTi18-9). The average grains size is 7-6 index, when welding without the TMF influence and the average grains size of the weld metal corresponds to 8 index, with separate inclusions of grains with 7 index when welding with the TMF influence. This is should increase the yield strength value of the weld metal in accordance with the data of Hall – Petch.

Some Feasibility Studies for Recycling of Steel Slag as a Useful Flux for Submerged Arc Welding

2020 ◽  
Vol 19 (02) ◽  
pp. 277-289
Author(s):  
Sumit Saini ◽  
Kulwant Singh
Keyword(s):  
Weld Metal ◽  
Arc Welding ◽  
Steel Slag ◽  
Welding Process ◽  
Feasibility Studies ◽  
Submerged Arc Welding ◽  
Bead Geometry ◽  
Weld Bead Geometry ◽  
Arc Welding Process ◽  
Submerged Arc

Protection of environment from industrialization and urbanization waste is the prime duty of engineers and researchers. Elimination of industrial waste completely is not possible because it is generally a byproduct of the process. It can be minimized by recycling or reusing. In this research, waste slag generated by steel plant is recycled as a useful flux for submerged arc welding. It is found that recycled slag is capable of producing acceptable weld bead geometry. The penetration achieved using recycled slag is 7.897[Formula: see text]mm, which is more than the penetration obtained using fresh flux, i.e. 6.027[Formula: see text]mm. The reinforcement produced by recycled slag is 2.632[Formula: see text]mm, which is close to the reinforcement obtained using fresh flux. It is further observed that chemistry of weld metal deposited using recycled slag is also at par with that of weld metal produced using fresh original flux. The amount of carbon present in weld metal produced by recycled slag is 0.15%, which is comparable to the percentage of carbon present in weld metal produced using fresh flux. The microstructure and microhardness obtained using recycled slag are also comparable with the microstructure and microhardness obtained using fresh flux. This research established the feasibility of recycling slag as a flux required for submerged arc welding process.

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