Processes of nonconsumable electrode welding with welding current modulation (review) part iii. modeling of the processes of TIG welding by modulated current

2020 ◽  
Vol 2020 (1) ◽  
pp. 3-14
Author(s):  
Boyi Wu ◽  
◽  
I.V. Krivtsun ◽  
2017 ◽  
Vol 904 ◽  
pp. 19-23
Author(s):  
Van Nhat Nguyen ◽  
Quoc Manh Nguyen ◽  
Dang Thi Huong Thao ◽  
Shyh Chour Huang

Welding dissimilar materials has been widely applied in industries. Some of them are considered this as a strategy to develop their future technology products. Aluminum alloy and stainless steel have differences in physical, thermal, mechanical and metallurgic properties. However, selecting a suitable welding process and welding rods can solve this problem. This research aimed to investigate the T-joint welding between A6061 aluminum alloy and SUS304 stainless steel using new welding rods, Aluma-Steel by the Tungsten Inert Gas (TIG) welding process. The mechanical properties, the characteristics of microstructure, and component analysis of the welds have been investigated by the mechanical testing, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). As a result, the fracture occurred at the adjacent area between welding seam and A6061 alloys plate. The thermal cracking appeared at central welding-seam along the base metals if high welding current. A large amount of copper elements found in the welds due to using the new welding rod, Aluma-Steel rod.


2019 ◽  
Vol 9 (23) ◽  
pp. 5260 ◽  
Author(s):  
Ngo Huu Manh ◽  
Nguyen Van Anh ◽  
Nguyen Van Tuan ◽  
Bin Xu ◽  
Murata Akihisa

This paper aims to develop a novel tungsten inner gas (TIG) welding torch in order to join thin sheets efficiently. Using a narrowing nozzle (constricted nozzle) inside a conventional TIG torch can critically improve the position accuracy of the tungsten electrode and also the arc plasma characteristics and heat input density. In order to evaluate the efficiency of this new torch, weld bead appearance and cross-section images were examined by an optical microscope, scanning electron microscope (SEM), and electron back scatter diffraction patterns (EBSD). The results showed that in all cases, the weld bead profile was stable without undercut and burn-through. Full penetration weld was seen. The width of weld bead on the bottom surface was increased much in comparison to conventional TIG welding. However, the results from SEM and EBSD images indicated that in the case of low welding current, the blowholes were found out on the side of the thinner material (SS400). The penetration of SUS430 material to SS400 material was not good. It seems that no fusion of SUS430 material to SS400 at the bottom surface can be seen. Meanwhile, no blowholes were seen in the case of high welding current. The penetration was better, and the fusion was reached on the bottom surface.


2018 ◽  
Vol 7 (3.6) ◽  
pp. 206
Author(s):  
P Jerold Jose ◽  
M Dev Anand

In this research, the effects of heat input on tensile properties and microstructure were investigated for super alloy Inconel-718 sheets weld by Tungsten Inert Gas (TIG) welding process. The tensile properties and microstructure of weld joints were evaluated. The experiment was conducted with six different combinations of welding parameters like welding current, voltage and welding speed, which were give in six different welding heat input combinations of welding parameters. The experimental results shows that the welding joints weld with low welding heat input was yield higher tensile properties. From the experimentation it was understand that the tensile properties increases when the welding heat input decrease. Drastic grain coarsening was evidenced when the heat input was increases. For the weld joints experimented in this research it was also observed that amount of laves phase was increased with increase in the welding heat input which is the major fact for noticeable variation in the ultimate tensile strength of the weld joints welded by TIG welding process with different welding heat input. 


2015 ◽  
Vol 819 ◽  
pp. 45-49 ◽  
Author(s):  
Shamsul Baharin Jamaludin ◽  
Mohd Zahir Abd Latif ◽  
Mohd Noor Mazlee ◽  
Kamarudin Hussin

The effect of welding current on the joining of mild steel and aluminum 6063 has been investigated. The joining was carried using a tungsten inert gas (TIG) welding. The welding currents used were 30 A to 80 A. The formation of intermetallic reaction layers (IML) and tensile shear strength of the joining were investigated. The result showed that tensile shear strength increased as welding current increased up to 55 A. Microstructural analysis showed that intermetallic reaction layer was formed at the interface between steel and aluminum alloy during welding process. The thickness of IML was decreased with decreasing welding current.


Author(s):  
Ngo Huu Manh ◽  
Nguyen Van Anh ◽  
Murata Akihisa ◽  
Hideno Terasaki

A study about influence of heat input on welding defects in vertical upward welding position for dissimilar material and thickness using a new variation of TIG welding torch is done with support of advanced inspection methods SEM and EBSD. With vertical upward welding position, control heat input plays an important role to keep the weld stabilization without defects. On the other hand, TIG welding process using a conventional TIG torch (conventional TIG welding process) has low efficiency and it is difficult to control heat input with high accuracy. So, it is considered that using conventional TIG torch is still a challenge for welding thin plates. In this case, a new variation of TIG torch has been developed. This torch used a constricted nozzle to improve plasma arc characteristics. As a result, it can control efficiently the heat input to prevent the excessive or insufficiency for joining thin sheets. For evaluation of welding quality, advanced examination methods SEM and EBSD were applied to directly observe the welding defects. From the results, the formation mechanism of blowhole inside weld zone in case of welding dissimilar material and thickness was discussed. It is pointed out that when sufficient welding current, the change from weld zone to base metal is uniform, no welding defects such as blowhole was seen. However, in case of low welding current, the thinner base metal is insufficient fusion and the change between weld zone and base metal is not uniform. The blowhole was observed at SS400 material side.


2020 ◽  
Vol 861 ◽  
pp. 52-56
Author(s):  
Kittipong Kimapong ◽  
Voraya Wattanajitsiri ◽  
Sakchai Chantasri ◽  
Surat Triwanapong

This paper aimed to study an overlap distance (OL) of hard-faced welding bead in a tungsten inert gas (TIG) welding on the JIS-S50C carbon steel surface. Hard-faced weld metal was produced on an outside surface of the cylinder, using TIG welding with a high chromium flux-cored wire electrode. Welding process parameters were a welding current of 150–210 A and a hard-faced layer of 1–3. The experimental results were summarized as follows. An increase in welding current increased the weld width and the penetration but decreased the weld convex. It also increased the hardness and wear resistance of hard-faced weld metal. The increase of a weld overlap distance resulted in a decrease in the dilution effect in weld metals and an increase in the hardness and wear resistance. An increase in the hard-faced weld metal layer also resulted in a decrease in the dilution effect, resulting in an increase in the hardness and wear resistance.


2012 ◽  
Vol 233 ◽  
pp. 384-387
Author(s):  
De Ping Jiang ◽  
Zong Xiang Yao

The TIG welding was used to weld AZ31B magnesium alloys. The results indicate that hot cracking is related to the chemical composition of the filler metal and the welding current. When the AZ40M alloy, with low content of Zn, is used for the filler metal, no hot cracking appears in the weld. While the AZ31B alloy is used as the filler metal, or with no filler metal, hot crack appears in the weld seam.The hot crack will appear when the weleding current is over one point.The reason of hot crack appeared is some low melting eutectic appearing in weld. Key word: TIG Welding;Magnesium Alloys; Hot Cracking; AZ31B


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