Mechanical, Microstructure, and Corrosion Characterization of Dissimilar Austenitic 316L and Duplex 2205 Stainless-Steel ATIG Welded Joints

Abstract

The present work analyzed the microstructure, mechanical, and corrosion properties of a dissimilar activated tungsten inert gas (ATIG) welded 2205 duplex stainless-steel (2205 DSS) plate and AISI 316L austenitic stainless steel (316L ASS) and compared them to conventional dissimilar welded tungsten inert gas (TIG). The mixing design method is a tool used to establish the optimal combined flux to achieve a full-penetrated weld bead in one single pass. A microstructure study was carried out by scanning electron microscopy (SEM). The ATIG and TIG fusion zones revealed a matrix ferrite structure with intragranular austenite, Widmanstätten needles, allotriomorphic austenite at the grain boundaries, and plate-like precipitates free of deleterious phases such as sigma and chi phases or second austinite owing to the moderate heat input provided of 0.8 kJ/mm. Ferrite volume proportion measurements were carried out utilizing the areas image processing software. The average ferrite volume proportion attained 54% in the ATIG weld zone; however, it decreased to 47% for the TIG weld zone. The results showed that the optimal flux composed by 91% Mn2O3 and 9% Cr2O3 allowed a full penetrated weld to be obtained in one single pass. However, a double side weld is required for conventional TIG processes. The values of the tensile (599 Mpa), hardness (235 HV), and impact test (267 J/cm2) measurements of ATIG welds were close to those of conventional TIG welds. The elaborated flux did not degrade the mechanical properties of the joint; on the contrary, it reinforced the strength property. The width of the ATIG heat-affected zone was narrower than that of TIG welding by 2.6 times, ensuring fewer joint distortions. The potentiodynamic polarization test results showed a better electrochemical behavior for ASS 316L than with the weldment and the parent metal of DSS 2205.

Dissimilar joining of duplex AISI 2304 stainless steel/austenitic AISI 321 stainless steel using resistance spot welding technique: Microstructural evolutions, tensile-shear properties, and fracture analysis

“…in this. 47 Li et al 48 joined 301LN cold-rolled ASS to Q235B mild steel via the RSW process. They could find columnar dendrites (CD) including the martensite phase ( α ′ ) as well as a low fraction of δ -ferrite phase and very tinny interdendritic (ID) austenite phase in the WM.…”

“…The microstructural analysis for WM could represent a ferritic-austenitic structure that mostly contained grain boundary, intergranular, and Widmansta¨tten austenite. 46 Touileb et al 47 analyzed inactivated and activated GTAW of AISI 316L/AISI 2205 DSS. They reported that the WM structure had a ferritic matrix with Widmansta¨tten needles, intragranular austenite, and allotriomorphic austenite in the grain boundary.…”

Experimental Study on the Flexural Properties of Concrete Beams Reinforced with Hybrid Steel/Fiber-Belt-Bars

“…Reinforcement corrosion is an important factor affecting the durability of reinforced concrete structures, and this poses a great threat to the safety of reinforced concrete (RC) structures [ 1 , 2 , 3 ]. Particularly, the corrosion in prestressed concrete bridge-beams provokes significant prestress losses, which induces cracking and excessive deflections during service conditions [ 4 , 5 ].…”

Effect of the Heat Input and Ageing Treatment on Microstructure and Mechanical Properties of AISI 317L Stainless Steel Dissimilar Welded Joints

“…In this sense, an important issue has been the evaluation of proper filler metals for welds of Mo-rich stainless steels, such as the AISI 317L stainless steel, specified for critical applications in onshore and offshore oil and gas processing units, chemical and petrochemical plants, paper and pulp industries and other facilities.For that, an investigation of the filler metal chemical composition relation to the δ-ferrite amount and to the elemental partitioning in the weld metal and HAZ has been carried out to keep the corrosion and mechanical properties of the welded joint similar to the base metal. Recently, duplex stainless steels have been investigated as filler metal to weld Mo-rich austenitic stainless steels to mitigate metallurgical and mechanical problems that arise due to the secondary phases precipitations during welding of austenitic stainless steels [8][9][10][11][12][13] . However, no studies were found in the literature specifically regarding this application for the 317L steel.…”