scholarly journals Analysis of the structure and selected properties of welds obtained by the CMT and MAG method

2020 ◽  
Vol 92 (1) ◽  
pp. 45-51
Author(s):  
Szymon Kwiecień ◽  
Wirginia Pilarczyk ◽  
Ewa Harapińska
Keyword(s):  
Mechanical Properties ◽  
Optical Microscopy ◽  
Heat Affected Zone ◽  
Welded Joints ◽  
Low Energy ◽  
Test Results ◽  
High Quality ◽  
Cold Metal Transfer ◽  
Cold Metal ◽  
Non Destructive

The article presents an analysis of the Cold Metal Transfer (CMT) method, including the process, advantages and application of the method. The joints made with low energy CMT method and classic MAG method were also compared. The paper presents the results of non-destructive penetrant tests of welded joints made of steel in the S235JR grade. Microscopic observations were made using optical microscopy and the hardness was measured in accordance with PN-EN ISO 6507-1:2007. The test results confirmed that the CMT process allows for the production of high-quality joints and a narrow heat-affected zone compared to the classic MAG welding method, and also provides good mechanical properties and elimination of spatter.

scholarly journals Study of Corrosion, Structural, and Mechanical Properties of EN AW-6082 and EN AW-7075 Welded Joints

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4349
Author(s):  
Tomasz Wojdat ◽  
Paweł Kustroń ◽  
Karol Jaśkiewicz ◽  
Jarosław Pabian
Keyword(s):  
Mechanical Properties ◽  
Welded Joints ◽  
Base Material ◽  
Lap Joints ◽  
The Body ◽  
Butt Joints ◽  
Cold Metal Transfer ◽  
7075 Alloy ◽  
Cold Metal ◽  
Structure Investigations

The purpose of the work was to test the welded joints of aluminum alloys EN AW-7075 and EN AW-6082, which are used to join individual structural elements of car bodies, e.g., B-pillar with the body. The joints were made using the low-energy cold metal transfer (CMT) arc welding method. The results of the structure investigations of lap and butt joints, as well as tests of mechanical properties are presented. The influence of linear energy and the way of arranging materials in lap joints on the possibility of hot cracks occurrence has been demonstrated. The shear strength of lap joints was equal to 150 MPa, while the tensile strength of butt joints was equal to 375 MPa. The highest hardness reduction was observed in the heat affected zone (HAZ) from the EN AW-7075 alloy side in the range of 98 to 138 HV 0.05. In addition, a significant reduction of the corrosion resistance in the transition zone between HAZ and the base material (EN AW-7075 alloy) in the medium salinity environment, corresponding to the sea conditions according to ASTM G85 was indicated.

scholarly journals Microstructure and mechanical properties of 2060 Al–Li alloy welded by alternating current cold metal transfer with high-frequency pulse current

2021 ◽  
Vol 40 (1) ◽  
pp. 214-227
Author(s):  
Liwei Wang ◽  
Huan Hu ◽  
Huan Yan ◽  
Ying Liu ◽  
Ziqin Wu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Welded Joints ◽  
High Frequency ◽  
Pulse Current ◽  
Pulse Frequency ◽  
Cold Metal Transfer ◽  
Cold Metal ◽  
Frequency Pulse

Abstract Al–Li alloy has been widely used in the aerospace field owing to its high strength and low density. In this study, alternating current cold metal transfer (AC CMT) along with a high-frequency pulse current technique was used to weld a 2060 Al–Li alloy using an ER5356 wire. The effect of pulse frequency on the arc shape, microstructure, and mechanical properties of the welded joints was examined, and mechanical performance testing was conducted. The results revealed that the arc diameter, arc length, and arc volume showed a trend of increasing first and then decreasing with an increase in the pulse frequency and reached their peak values when the pulse frequency was 50 kHz. Coupling the welding process with a high-frequency pulse resulted in grain refinement, which was attributed to the stirring action of the arc force. Both the porosity levels and grain size decreased with increasing frequency. When the pulse frequency was 70 kHz, the porosity level was the lowest, and the grain size was refined to 24.1 μm. The tensile strength of the welded joints also increased with the pulse frequency, and a maximum tensile strength of 249 MPa was observed at 70 kHz.

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.

Influence of backing materials towards the fatigue strength of butt-welded joints

2011 ◽  
Vol 225 (8) ◽  
pp. 1798-1807 ◽  
Author(s):  
M H Kim ◽  
H J Kim ◽  
J H Han ◽  
J M Lee ◽  
Y D Kim ◽  
...  
Keyword(s):  
Finite Element ◽  
Fatigue Strength ◽  
Welded Joints ◽  
Fatigue Tests ◽  
Experimental Results ◽  
Finite Element Analyses ◽  
Cold Metal Transfer ◽  
Notch Stress ◽  
Effective Notch Stress ◽  
Cold Metal

The purpose of this study is to investigate the fatigue strength of butt-welded joints with special attention paid to employing different kinds of backing plates. The effect of the under-matched weld was also considered. Four different cases of backing scenarios for butt-welded specimens such as steel backing, ceramic backing, CMT (no backing by cold metal transfer) and UM (under-matched welded specimen) were investigated. A series of fatigue tests was performed to compare the fatigue strength of butt-welded joints with respect to different backing scenarios. Effective notch stress was used for the interpretation of fatigue strength of butt-welded specimens with backing plates based on finite element analyses for calculating fatigue notch factors. When results were presented from the effective notch stress, all backing scenarios considered in this study exhibited the fatigue strengths corresponding to the FAT 225 curve. From the experimental results of this study, it was determined that the fatigue strengths of butt-welded joints were found to be in the order of CMT, ceramic backing, UM, and steel backing. No significant decrease in fatigue strength, however, was observed when backing plates were steel backing and ceramic backing types.

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