Abstract
In this paper, 8.0 mm thickness 2205 duplex stainless steel (DSS) workpieces were welded with a keyhole tungsten inert gas (K-TIG) welding system under different welding speeds. After welding, the morphologies of the welds under different welding speed conditions were compared and analyzed. The microstructure, two-phase ratio of austenite/ferrite, and grain boundary characteristics of the welded joints were studied, and the microhardness and tensile properties of the welded joints were tested. The results show that the welding speed has a significant effect on the weld morphology, the two-phase ratio, grain boundary misorientation angle (GBMA), and mechanical properties of the welded joint. When the welding speed increased from 280 mm/min to 340 mm/min, the austenite content and the two-phase ratio in the weld metal zone (WMZ) decreased. However, the ferrite content in the WMZ increased. The proportion of the Σ3 coincident site lattice grain boundary (CSLGB) decreased as the welding speed increased, which has no significant effect on the tensile strength of welded joints. The microhardness of the WMZ and the tensile strength of the welded joint gradually increased when the welding speed was 280–340 mm/min. The 2205 DSS K-TIG welded joints have good plasticity.
Highlights
Accepted: 14 June 20212205 Duplex Stainless Steel (DSS) is a functional integrated material with high strength and excellent corrosion resistance
The high-purity argon was plates with a thickness of mm were selected as the base material (BM), and its chemical applied as the protective gas on the front and back of the workpieces, and the gas flow composition shown inspecific
The microhardness of all weld metal zone (WMZ) were higher than that of the BM. This was because the two-phase ratio of austenite/ferrite in the WMZ decreased significantly after welding
Summary
2205 Duplex Stainless Steel (DSS) is a functional integrated material with high strength and excellent corrosion resistance It is composed of two phases of ferrite and austenite, and the content of both is close to 1:1 [1,2]. They reported that the are fine-grained that and2205 mechanical of the welded joints different fusion due with a higher ratiorate showed better impact toughness, while thebeam coarser-grained to zone the difference in theγ/α cooling corresponding to different high-energy welding fusion zone with a higher α/γ ratio showed properties. The current research mainlyis focuses onhigh-energy the effect ofbeam cooling rate on Keyhole tungsten inert gas (K-TIG) welding a kind of welding the microstructure of the welded joint and lacks the mechanism analysis method It can be welded in a single-pass welding and formed on both sides without of fill-the microstructure evolution during the welding process. The evolution law of the two-phase ratio, grain boundary and misorientation
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