Microstructure and Corrosion Properties of Austenitic and Duplex Stainless Steel Dissimilar Joints

Abstract

In several applications duplex stainless steels should be joint welded to conventional austenitic stainless steels. In this research LDX 2101 lean duplex stainless steel sheets were welded to conventional 304 austenitic stainless steels, using gas tungsten arc welding. For the welded joints three different welding rods were used: ER 308L, ER 309LSi, and ER 2209. For gas shielding two different shielding gases were used: argon and argon +2% nitrogen. It was found that the nitrogen addition to the shielding gas promoted austenite formation in the weld metal. It was also found Schaeffler-diagram modified by Outokumpu showed a very good estimation to the ferrite content and chemical composition of the weld metal. The ferrite content estimated by the Outokumpu-diagram, showed a close correlation to measured ferrite contents, the highest error was 30%. In case of the chemical composition of the weld metal, the Cr- and Ni-contents were estimated with a maximum of 15% error. In terms of the corrosion resistance, the best pitting corrosion resistance was achieved using the 308L welding rod with argon shielding gas, where the weight loss was 1.6% after the 24 hours immersion test.

Investigation of Spinodal Decomposition in Isothermally Heat Treated LDX 2101 type Duplex Stainless Steel at 475 °C

“…It can drop the impact energy of corrosion-resistant steel from the original value of 140-150 J to less than 10 J [5]. On the other hand, α'-phase is rich in Cr, therefore its presence decreases the concentration of this element in the adjacent grains causing a reduction in the corrosion resistance [6][7][8][9][10][11][12].…”

Microstructure and Mechanical Properties of Laser-Welded Joints between DP590 Dual-Phase Steel and 304 Stainless Steel with Preset Nickel Coating

“…Xie et al [ 14 ] investigated the microstructural and mechanical properties of the ultrasonic spot welding of the dissimilar materials TiNi/Ti6Al4V using a pure Al coating. The study revealed that the dissimilar materials TiNi/Ti6Al4V had been successfully joined and the tensile shear load reached a maximum value of 931 N. Varbai et al [ 15 ] used gas tungsten arc welding to obtain a joint between lean duplex stainless steel and 304 austenitic stainless steel. Their investigations revealed that the best pitting corrosion resistance was achieved using a 308L welding rod with argon shielding gas, with a weight loss of 1.6% after the 24 h immersion test.…”