Optimization of TIG Welding Influenced by Nb+Ta Based Filler Wire for Ferritic Stainless Steel

The possible sources causing weld metal hydrogen and oxygen pick-up during offshore hyperbaric tie-in TIG welding have been identified and simulated at a hyperbaric chamber pressure of 12 bar, i.e. 110 meter sea depth. The base material was supermartensitic 13% Cr stainless steel. Matching filler wire was used. The weld metal hydrogen and oxygen pick-up from water vapor in the shielding and chamber gases has been investigated by girth welding of pipes. Moist chamber gas seems to have insignificant effect on hydrogen and oxygen pick-up. The largest contribution is from moist shielding gas. Most of the hydrogen content in the supermartensitic welds is diffusible. By applying post-heat, it is possible to reduce the hydrogen content in the weld metal. Microcracks in the cap were observed for welds deposited with 14 mbar water vapor in the shielding gas (117 ppm) and above. Microcracks in the root welds were not observed, which was also confirmed for self restrained cracking tests. During constant load test at 150 MPa simulating hydrostatic testing of pipelines, the microcracks grew, and for the weld deposited with fully moistened shielding gas (175 ppm), a macrocrack appeared in the centre of the capping pass longitudinally to the welding direction. Crack Tip Opening Displacement (CTOD) values based on Single Edge Notched Bend (SENB) testing were all low, and the high constraint of the SENB specimen did not show any effects of hydrogen on fracture toughness. CTOD values based on Single Edge Notched Tension (SENT) testing decreased with increasing shielding gas moisture contents. For specimens without microcracks it was possible to increase the CTOD (SENT) values by post-heat, close to the toughness observed for specimens deposited with dry shielding gas.

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GMAW dissimilar welding of AISI 409 ferritic stainless steel to AISI 316L austenitic stainless steel by using AISI 308 filler wire

Engineering Science and Technology an International Journal ◽

10.1016/j.jestch.2017.08.002 ◽

2017 ◽

Vol 20 (4) ◽

pp. 1334-1341 ◽

Cited By ~ 4

Author(s):

Nabendu Ghosh ◽

Pradip Kumar Pal ◽

Goutam Nandi

Keyword(s):

Stainless Steel ◽

Austenitic Stainless Steel ◽

Ferritic Stainless Steel ◽

Dissimilar Welding ◽

Filler Wire ◽

Aisi 316L ◽

316L Austenitic Stainless Steel

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Effect of Ternary Fluxes on Depth of Penetration in A-TIG Welding of AISI 409 Ferritic Stainless Steel

Procedia Materials Science ◽

10.1016/j.mspro.2014.07.485 ◽

2014 ◽

Vol 5 ◽

pp. 2402-2410 ◽

Cited By ~ 16

Author(s):

G. Venkatesan ◽

Jimin George ◽

M. Sowmyasri ◽

V. Muthupandi

Keyword(s):

Stainless Steel ◽

Ferritic Stainless Steel ◽

Tig Welding ◽

Depth Of Penetration ◽

A Tig Welding

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Effects of ATIG Welding on Weld Shape, Mechanical Properties, and Corrosion Resistance of 430 Ferritic Stainless Steel Alloy

Metals ◽

10.3390/met10030404 ◽

2020 ◽

Vol 10 (3) ◽

pp. 404 ◽

Cited By ~ 2

Author(s):

Kamel Touileb ◽

Abousoufiane Ouis ◽

Rachid Djoudjou ◽

Abdeljlil Chihaoui Hedhibi ◽

Hussein Alrobei ◽

...

Keyword(s):

Mechanical Properties ◽

Stainless Steel ◽

Corrosion Resistance ◽

Ferritic Stainless Steel ◽

Welding Process ◽

Tig Welding ◽

Inert Gas ◽

Steel Alloy ◽

Stainless Steel Alloy ◽

Mechanical Properties And Corrosion

Flux activated tungsten inert gas (ATIG) welding is a variant of tungsten inert gas (TIG) welding process with high production efficiency, high quality, low energy consumption, and low cost. The study of activating flux mechanism by increasing weld penetration has direct significance in developing flux and welding process. This study has been conducted on 430 ferritic stainless steel alloy. Design of experiment is used to get the best formulation of flux. Based on Minitab17 software, nineteen compositions of flux were prepared using the mixing method. Fluxes are combinations of three oxides (MoO3-TiO2-SiO2). Using the optimizer module available in Minitab 17 software, the best formulation was obtained to achieve the best weld depth. Hence, the obtained depth is twice greater than that achieved by conventional TIG welding. Moreover, mechanical properties and corrosion resistance have been investigated for TIG and ATIG welds respectively in tensile, impact, and hardness tests, and in potentiodynamic polarization measurement test.

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