scholarly journals Porosity Formation in Thin Welded Joints of Al–MG–LI Alloys

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 348
Author(s):  
Tatyana Olshanskaya ◽  
Elena Fedoseeva
Keyword(s):  
Phase Composition ◽  
Weld Metal ◽  
Fusion Zone ◽  
Residence Time ◽  
Welded Joints ◽  
Liquid State ◽  
Pore Formation ◽  
Vacuum Treatment ◽  
Thermal Vacuum ◽  
Thermal Vacuum Treatment

This work is about the study of the correlation of pore formation in welded joints of Al–MG–LI alloy with zirconium additives with the state of the base metal, thermal vacuum treatment, and welding technologies MIG and EBW. Metallographic analysis has been carried out, the phase composition of the alloy and weld metal has been investigated, and thermal cycles of welding have been calculated, allowing to estimate the residence time of metal in the alloying zone and weld metal in the liquid state. The nature of the allocation of strengthening fine-dispersed phases in the welded joints of the alloy has been determined. The regularity and character of pore formation in welded joints depending on the applicable thermal vacuum treatment (TVT) and welding technology have been revealed. It was established that TVT with subsequent hardening and aging has no effect on the phase composition of the alloy. However, this type of treatment contributes to the formation of a more homogeneous and uniform nature of the separation of fine-dispersed strengthening phases. It was revealed that the MIG technology (metal with and without TVT) is characterized by a large length of the fusion zone, the high residence time of metal in the fusion zone and weld metal in the liquid state, and the formation of pores. Phase formation in the temperature range of the beginning and end of the alloy crystallization occurs not only in the weld at the final stage of crystallization but also in the fusion zone, which may induce pore formation, whereas EBW welding shows the opposite trend and no pores. It was found that EBW technology prevents pore formation and makes it possible to obtain welded joints of 1420 Al alloys of the required quality.

Effect of a Thermal-Vacuum Treatment and X-Ray Radiation on the Morphology and Electrical Properties of Titanium Oxide Nanocoatings

2019 ◽  
Vol 92 (7) ◽  
pp. 883-892
Author(s):  
A. S. Kochetkova ◽  
E. A. Sosnov ◽  
A. A. Malkov ◽  
V. V. Antipov ◽  
N. A. Kulikov ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Titanium Oxide ◽  
Vacuum Treatment ◽  
Thermal Vacuum ◽  
X Ray ◽  
Thermal Vacuum Treatment

Degradation of the reflectivity of white anodic-oxide coatings in thermal vacuum treatment

1997 ◽  
Vol 64 (5) ◽  
pp. 678-682 ◽  
Author(s):  
V. N. Kuznetsov ◽  
A. A. Lisachenko ◽  
I. V. Ivanova ◽  
V. A. Konnov
Keyword(s):  
Vacuum Treatment ◽  
Anodic Oxide ◽  
Oxide Coatings ◽  
Thermal Vacuum ◽  
Thermal Vacuum Treatment

scholarly journals Effect of weld metal composition on impact toughness properties of shielded metal arc welded ultra-high hard armor steel joints

2020 ◽  
Vol 29 (1) ◽  
pp. 186-194
Author(s):  
V. Balaguru ◽  
Visvalingam Balasubramanian ◽  
P. Sivakumar
Keyword(s):  
Impact Toughness ◽  
Weld Metal ◽  
Welded Joints ◽  
Weight Ratio ◽  
High Hardness ◽  
High Strength ◽  
Solidification Mode ◽  
Austenitic Phase ◽  
Ferrite Number ◽  
Steel Joints

AbstractNowadays, ultra-high hard armor (UHA) steels are employed in armor tracked vehicle (ATV) construction because of their high hardness, high strength to weight ratio, and excellent toughness. UHA steels are usually welded using austenitic stainless steel (ASS) welding consumables, to avoid hydrogen-induced cracking (HIC). The use of ASS consumables to weld the above steel was the only available remedy because of higher solubility of hydrogen in the austenitic phase. In this investigation, an attempt was made to investigate the effect of ASS consumables (with different Creq/Nieq ratio) on solidification mode, impact toughness and microstructural characteristics of shielded metal arc (SMA) welded UHA steel joints. The welded joints were characterised based on impact toughness properties, hardness, and microstructural features. As the ferrite number increases with an increase in Creq/Nieq ratio result in different solidification mode (A, FA, F). It is also found that ferrite number of weld metal has appreciable influence on impact toughness and has inversely proportional relationship with impact toughness of the welded joints.

scholarly journals DEVELOPMENT OF A TECHNOLOGICAL PROCESS FOR MANUFACTURING WELDED STRUCTURES

2021 ◽  
Vol 4 (5) ◽  
pp. 35-44
Author(s):  
R. El'cov
Keyword(s):  
Phase Composition ◽  
Laser Welding ◽  
Strain Amplitude ◽  
Welded Joints ◽  
Structural Phase ◽  
Diagnostic Methods ◽  
Aluminum Lithium ◽  
Aluminum Lithium Alloys ◽  
First Time ◽  
Lithium Alloys

the main goal of this article is to obtain welded permanent joints of modern thermally hardened aluminum and aluminum-lithium alloys made by laser welding, having mechanical characteristics (temporary tensile resistance, yield strength, elongation at break) and structural-phase composition close to or equal to the base alloy. It is shown for the first time that by controlling the parameters of heat treatment of samples with a welded joint of all studied aluminum-lithium alloys, it is possible to purposefully influence the formation of the specified mechanical properties of the weld by changing the structural and phase composition of the weld. The evolution of the struc-tural and phase composition of welded joints of thermally hardened aluminum and aluminum-lithium alloys has been investigated using modern independent diagnostic methods: for the first time, the use of synchrotron radia-tion diffractometry in combination with high-resolution transmission, scanning electron and optical microscopy. The dependences of the increment of deformation under cyclic loading with amplitudes exceeding the elastic limit on temperature are established. For untreated welded joints, it was found that at +85 C, the inhomogeneity of the deformation increment increases, and its speed increases by 8 times for alloy 1461, 5 times for alloy 1420 and 1.5 times for alloy 1441. At a temperature of -60 0C, alloys 1420 and 1461 have hardening stages, during which the value of deformation decreases at given boundary stress values. At +20 0C, there is a uniform increment of defor-mation and an increase in the amplitude of deformation with an increase in the amplitude of stress. At +85 0C, the strain amplitude does not change with increasing stress amplitude, its value is 0.55-0.5 of the strain amplitude at +20 0C. Based on the research results, technological techniques have been developed that allow obtaining me-chanical characteristics and structural-phase compositions of welded joints close to the main alloy during laser welding of aviation thermally hardened aluminum and aluminum-lithium alloys of the Al-Mg-Cu. Al-Mg-Li, Al-Cu-Mg-Li, Al-Cu-Li systems.

scholarly journals Peculiarities of alloying of weld metal of high-strength aluminium alloy welded joints with scandium

2014 ◽  
Vol 2014 (5) ◽  
pp. 28-32 ◽  
Author(s):  
V.E. Fedorchuk ◽  
◽  
O.S. Kushnaryova ◽  
T.A. Alekseenko ◽  
Yu.V. Falchenko ◽  
...  
Keyword(s):  
Weld Metal ◽  
Aluminium Alloy ◽  
Welded Joints ◽  
High Strength
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