Welding of Internally Clad X65 Pipes With Precipitation Strengthened Ni-Based Filler Metals

2017 ◽  
Author(s):  
Graciela C. Penso ◽  
Boian T. Alexandrov
Keyword(s):  
Yield Strength ◽  
Weld Metal ◽  
Parameter Optimization ◽  
Filler Metal ◽  
Gas Metal Arc Welding ◽  
Welding Parameter ◽  
Cold Metal Transfer ◽  
Alloy 625 ◽  
Metal Yield ◽  
Cold Metal

X65 steel pipes internally clad with Alloy 625 used in subsea oil extraction are normally welded together with Alloy 625 filler metal. For pipe reeling applications, DNV-OS-F101 requires pipe girth welds to overmatch base metal yield strength with 100 MPa. Since Alloy 625 filler metal does not meet this requirement, Ni-base super alloys 718 and 282 were considered as potential welding consumables for reeling applications. The solidification behavior in weld metal of these alloys diluted with Alloy 625 pipe ID cladding was evaluated using thermodynamic simulations. The response to precipitation hardening by multiple reheat cycles was studied by producing multilayer buildups with cold metal transfer (CMT) and pulsed gas metal arc welding (GMAWp) processes. Weld buildup of Alloy 718 exhibited insufficient hardening response and yield strength, while Alloy 282 met the DNV overmatch requirement. Successful narrow groove welding of X65 pipes with Alloy 282 was performed using CMT process. Welding parameter optimization allowed resolving centerline solidification cracking and lack of fusion defects. The weld metal yield strength was lower than in the multipass buildup, which was attributed to lower number of reheats in groove welding. Meeting the overmatch requirement for yield strength in Alloy 282 groove welds requires further parameter optimization.

scholarly journals Effect of Filler Metal Type on Microstructure and Mechanical Properties of Fabricated NiAl Bronze Alloy Using Wire Arc Additive Manufacturing System

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 513
Author(s):  
Jae Won Kim ◽  
Jae-Deuk Kim ◽  
Jooyoung Cheon ◽  
Changwook Ji
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Additive Manufacturing ◽  
Filler Metal ◽  
Gas Metal Arc Welding ◽  
Metal Wire ◽  
Cold Metal Transfer ◽  
Metal Type ◽  
Cold Metal ◽  
Wire Arc Additive Manufacturing

This study observed the effect of filler metal type on mechanical properties of NAB (NiAl-bronze) material fabricated using wire arc additive manufacturing (WAAM) technology. The selection of filler metal type is must consider the field condition, mechanical properties required by customers, and economics. This study analyzed the bead shape for representative two kind of filler metal types use to maintenance and fabricated a two-dimensional bulk NAB material. The cold metal transfer (CMT) mode of gas metal arc welding (GMAW) was used. For a comparison of mechanical properties, the study obtained three specimens per welding direction from the fabricated bulk NAB material. In the tensile test, the NAB material deposited using filler metal wire A showed higher tensile strength and lower elongation (approx. +71 MPa yield strength, +107.1 MPa ultimate tensile strength, −12.4% elongation) than that deposited with filler metal wire B. The reason is that, a mixture of tangled fine α platelets and dense lamellar eutectoid α + κIII structure with β´ phases was observed in the wall made with filler metal wire A. On the other hand, the wall made with filler metal wire B was dominated by coarse α phases and lamellar eutectoid α + κIII structure in between.

scholarly journals Effect of different variants of filler metal S Ni 6625 on properties and microstructure by additive layer manufactured using CMT process

2021 ◽  
Author(s):  
Manuela Zinke ◽  
Stefan Burger ◽  
Julius Arnhold ◽  
Sven Jüttner
Keyword(s):  
Weld Metal ◽  
Filler Metal ◽  
Welding Process ◽  
Travel Speed ◽  
Cold Metal Transfer ◽  
Thin Walled Structures ◽  
Thin Walled ◽  
Cold Metal ◽  
Hardness Values ◽  
Wire Feed

AbstractThe influence of arc energy and different filler metal composition on the mechanical properties and macro- and microstructure of additively welded thin-walled structures of Ni-based alloy were investigated using four different variants commercially available solid wire electrodes of type S Ni 6625. As the welding process, the Cold Metal Transfer (CMT) process was used. The heat input and cooling rate were varied by adjusting wire feed and travel speed. The results show that an increase in arc energy leads to longer t10/6 cooling times. This leads to an increase in the dendrite arm spacing and thus to a reduction in the strength values and hardness of the thin-walled structures. The higher Fe-containing variant of S Ni 6625 produces the highest strength and hardness values, while the W-alloyed solid wire electrode produces the lowest values. The porosity in the walled structures was very low, and unacceptable weld defects, hot cracks and lack of fusion did not occur. Segregations occur in all weld metal specimens. While niobium, molybdenum and titanium are the preferred segregations in the Nb-alloyed Ni 6625 type weld metal, only Mo is present in the W-alloyed Ni 6660 type weld metal.

scholarly journals Influence of post weld heat treatment on tensile properties of cold metal transfer (CMT) arc welded AA6061-T6 aluminium alloy joints

2019 ◽  
Vol 28 (1) ◽  
pp. 135-145 ◽  
Author(s):  
Addanki Ramaswamy ◽  
Sudersanan Malarvizhi ◽  
Visvalingam Balasubramanian
Keyword(s):  
Heat Treatment ◽  
Tensile Properties ◽  
Gas Metal Arc Welding ◽  
Weight Ratio ◽  
Welding Process ◽  
Metal Transfer ◽  
Post Weld Heat Treatment ◽  
Cold Metal Transfer ◽  
Cold Metal ◽  
Weld Heat

AbstractAluminium alloys of 6xxx series are widely used in the fabrication of light weight structures especially, where high strength to weight ratio and excellent weld-ability characteristics are desirable. Gas metal arc welding (GMAW) is the most predominantly used welding process in many industries due to the ease of automation. In this investigation, an attempt has been made to identify the best variant of GMAW process to overcome the problems like alloy segregation, precipitate dissolution and heat affected zone (HAZ) softening. Thin sheets of AA6061-T6 alloy were welded by cold metal transfer (CMT) and Pulsed CMT (PCMT). Among the two joints, the joint made by PCMT technique exhibited superior tensile properties due to the mechanical stirring action in the weld pool caused by forward and rearward movement of the wire along with the controllable diffusion rate at the interface caused by shorter solidification time. However, softening still exists in the welded joints. Further to increase the joint efficiency and to minimize HAZ softening, the joints were subjected to post weld heat treatment (PWHT). Approximately 10% improvement in the tensile properties had been observed in the PWHT joints due to the nucleation of strengthening precipitates in the weld metal and HAZ.

Studies on cold metal transfer welding of aluminium alloy 6061-T6 using ER 4043

2020 ◽  
Vol 234 (7) ◽  
pp. 924-937
Author(s):  
R Pramod ◽  
N Siva Shanmugam ◽  
CK Krishnadasan
Keyword(s):  
Mechanical Properties ◽  
Aluminium Alloy ◽  
Pressure Vessel ◽  
Weld Zone ◽  
Welding Process ◽  
Metal Transfer ◽  
Welding Parameter ◽  
Cold Metal Transfer ◽  
Cold Metal ◽  
Alloy 6061

Aluminium alloy 6061-T6 is utilized in aerospace industry for developing pressure vessel liner. Cold metal transfer is a promising welding process used in fabricating aluminium structures. The present work is focussed to achieve an optimum welding parameter for joining a 3.5-mm thick pressure vessel and to examine the mechanical properties and metallurgical nature of the weldment. The welded joint was evaluated as defect free using radiography test. The joint efficiency (66.61%) and measured microhardness of weldment (59.78 HV) exhibited promising results. The effect of grain coarsening in the heat affected zone (HAZ) and weld zone is attributed to the thermal gradients during welding. Dissipation of small amounts of strengthening elements Si and Mg during welding leads to reduction in mechanical properties. X-ray diffraction peaks revealed the presence of intermetallic Al–Si and Fe–Si in the weld zone. Fractography examination confirms the ductile type of failure in the fractured surface of the tensile samples.

Weldability and Distortion of Mg AZ31-to-Galvanized Steel SPOT Plug Welding Joint by Cold Metal Transfer Method

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
R. Cao ◽  
Q. W. Xu ◽  
H. X. Zhu ◽  
G. J. Mao ◽  
Q. Lin ◽  
...  
Keyword(s):  
Mild Steel ◽  
Weld Metal ◽  
Base Metal ◽  
Metal Transfer ◽  
Galvanized Steel ◽  
Feed Speed ◽  
Process Variables ◽  
Cold Metal Transfer ◽  
Wire Feed Speed ◽  
Cold Metal

In this study, cold metal transfer (CMT) plug welding of 1 mm thick Mg AZ31 to 1 mm thick hot-dipped galvanized mild steel (i.e., Q235) was studied. Welding tests were performed and the process variables optimized with Mg AZ61 wire and 100% argon shielding gas for a plug weld located in the center of the 25 mm overlap region. It was found that it is feasible to join 1 mm thick Mg AZ31 workpiece to 1 mm thick galvanized mild steel using CMT plug welding. The optimized process variables for CMT plug welding Mg AZ31-to-galvanized mild steel were a wire feed speed of 10.5 m/min, a predrilled hole with a diameter of 8 mm in Mg AZ31 workpiece and a welding time of 0.8 s. CMT plug welded Mg AZ31-to-galvanized mild steel joints were composed of the fusion zone between Mg AZ31 base metal and Mg weld metal, Mg weld metal (i.e., combined base metal, filler wire and Zn coating), and the brazing interface between magnesium weld metal and galvanized mild steel. The brazing interface mainly consisted of Al, Zn, Mg, Si intermetallic compounds and oxides (i.e., Fe3Al, Mg2Si, MgZn, and MgZn2), and magnesium solid solution. The static strength of CMT welded-brazed Mg AZ31-galvanized steel was determined primarily by the strength and area of the brazed interface and thickness of the intermetallic reaction layer.

A52M/SA52 Dissimilar Metal RPV Repair Weld: Experimental Evaluation and Post-Weld Characterizations

2020 ◽  
Author(s):  
Iikka Virkkunen ◽  
Mikko Peltonen ◽  
Henrik Sirén ◽  
Pekka Nevasmaa ◽  
Caitlin Huotilainen ◽  
...  
Keyword(s):  
Pressure Vessel ◽  
Arc Welding ◽  
Nuclear Power ◽  
Gas Metal Arc Welding ◽  
Metal Transfer ◽  
Reactor Pressure Vessel ◽  
Cold Metal Transfer ◽  
Metal Arc Welding ◽  
Cold Metal ◽  
Reactor Pressure

Abstract Aging management of the existing fleet of nuclear power plants is becoming an increasingly important topic, especially as many units are approaching their design lifetimes or are entering long-term operation. As these plants continue to age, there is an increased probability for the need of repairs due to extended exposure to a harsh environment. It is paramount that qualified and validated solutions are readily available. A repair method for a postulated through cladding crack into the low alloy steel of a nuclear power plant’s reactor pressure vessel has been investigated in this study. This paper is part of larger study that evaluates the current possibilities of such repair welds. The present paper documents the weld-trials and method selection. A parallel paper describes numerical simulations and optimization of weld parameters. The presented weld-trial represents a case where a postulated crack has been excavated and repaired using a nickel base Alloy 52M filler metal by gas metal arc welding-cold metal transfer with a robotic arm. A SA235 structural steel has been used as a base material in this weld-trial. No pre-heating or post-weld heat treatment will be applied, as it would be nearly impossible to apply these treatments in a reactor pressure vessel repair situation. While Alloy 52M presents good material properties, in terms of resistance to environmentally assisted degradation mechanisms, such as primary water stress corrosion cracking, it is notoriously difficult to weld. Some difficulties and challenges during welding include a sluggish weld puddle, formation of titanium and/or aluminium oxides and its susceptibility to lack of fusion defects and weld metal cracking, such as ductility dip cracking and solidification cracking. Moreover, gas metal arc welding-cold metal transfer is not traditionally used in the nuclear industry. Nonetheless, it presents some interesting advantages, specifically concerning heat input requirements and automation possibilities, as compared to traditional welding methods. The mechanical properties, in terms of indentation hardness, and microstructure of a weld-trial sample have been evaluated in this study. The fusion boundary and heat affected zone were the main areas of focus when evaluating the mechanical and microstructural properties. Detailed microstructural characterization using electron backscatter diffraction and nanoindentation were performed across the weld interface. Based on these results, the gas metal arc welding cold metal transfer is seen as a potential high-quality weld method for reactor pressure vessel repair cases.

Stability analysis of the Cold Metal Transfer (CMT) brazing process for galvanized steel plates with ZnAl4 filler metal

2019 ◽  
Vol 103 (5-8) ◽  
pp. 2485-2494
Author(s):  
Gustavo Henrique Truppel ◽  
Matthias Angerhausen ◽  
Alexandros Pipinikas ◽  
Uwe Reisgen ◽  
Luiz Eduardo dos Santos Paes
Keyword(s):  
Stability Analysis ◽  
Filler Metal ◽  
Metal Transfer ◽  
Steel Plates ◽  
Galvanized Steel ◽  
Cold Metal Transfer ◽  
Cold Metal

ANALYSIS OF THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF DUAL PHASE STEEL UNDER THE EFFECTS OF DIFFERENT BRAZING RATES

2012 ◽  
Vol 1381 ◽  
Author(s):  
A.F. Miranda Pérez ◽  
I. Calliari ◽  
K. Brunelli ◽  
F.A. Reyes Valdés ◽  
G. Y Pérez Medina
Keyword(s):  
Mechanical Properties ◽  
Intermetallic Compounds ◽  
Dual Phase Steel ◽  
Filler Metal ◽  
Compound Layer ◽  
Metal Transfer ◽  
Process Conditions ◽  
Dual Phase ◽  
Cold Metal Transfer ◽  
Cold Metal

ABSTRACTEnvironmental, concerns regarding reducing CO2 emissions and the drive of having better fuel economy have already enthused the car manufacturer to use the weight materials having better mechanical properties. Automotive industry has shown a great interest in Dual Phase steels due to the possibility of reducing weight of vehicles and increasing the passenger safety at a very competitive cost. Automotive applications unavoidably entail welding and joining in the manufacturing process and the fatigue resistance of welded joints due to the integrity and safety requirements. The variation of welding parameters (voltage, current and speed of welding) affects weld performance, mechanical, and metallurgical properties.The CMT (Cold Metal Transfer) braze welding is a relatively new technology that partially decouples the arc electrical transients from the filler wire feed rate. It allows reducing the heat required for welding and permits higher joining speeds.The aim of this work is to study the interfacial microstructures and intermetallic compounds produced by cold metal transfer welding of two plates of galvanized DP600 dual phase steel with CuSi3 as filler metal. The study was performed by applying a CMT braze welding with three different joining speeds. The welded microstructures and microhardness were determined and related to the welding process conditions.A small HAZ, constituted by martensite, bainite and coarse ferrite grains, has been highlighted. Furthermore, an intermetallic Fe-Si-Cu compound layer formed at the interface between steel and filler metal. The joining speed sways the size of ZTA since the heat input Q affects the phase transformation in the weld and heat affected zoneThis parameter also affects the thickness of the compound layer and the size of precipitates in the filler metal, likewise the mechanical characteristics. The fracture starts at the interface steel-copper where intermetallic compounds formed.

Erratum to: Mechanisms of weld pool flow and slag formation location in cold metal transfer (CMT) gas metal arc welding (GMAW)

2017 ◽  
Vol 61 (6) ◽  
pp. 1287-1287 ◽  
Author(s):  
Md. R. U. Ahsan ◽  
Muralimohan Cheepu ◽  
Rouholah Ashiri ◽  
Tae-Hoon Kim ◽  
Chanyoung Jeong ◽  
...  
Keyword(s):  
Weld Pool ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Metal Transfer ◽  
Slag Formation ◽  
Cold Metal Transfer ◽  
Metal Arc Welding ◽  
Cold Metal
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