| Effects of Oxygen Contents in Shielding Gas on the Properties of Ferritic Stainless Steel GTA Weld |
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Won-Bae Lee, Sang-Ho Uhm, In-Su Woo |
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| Abstract |
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The properties of GTA weld for ferritic stainless steel have been studied with different O₂ contents in Ar shielding gas at the constant welding speed. A small amount of O₂ (0.01~1.0%) was mixed in Ar shielding gas in order to improve the weld penetration. The fully penetrated GTA weld was acquired at 160A weld current shielded by pure Ar gas. Addition of oxygen larger than 0.1% made a full penetration at lower weld current than 160A. The small addition of O₂ in Ar shielding gas improved the penetration properties of GTA weld because the O₂ in the molten pool accelerated the flow of molten pool and changed the flow pattern from outward to inward direction. The impact energy and DBTT (Ductile- Brittle-Transition-Temperature) of the GTA weld shielded by Ar+O₂ (less 0.3%) was similar and the corrosion properties of GTA weld was slightly inferior to those of GTA weld shielded by pure Ar gas. |
| Key Words:
Ferritic stainless steel GTA weld, Shielding gas compositions, Penetration |
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