Study On The Properties Of Super304H Steel Welded Joints By TIG Welding Process

Super304H steel is a kind of new and economic 18-8 austenitic stainless steel, which has been used for more than ten years in foreign countries. But in our country, it is at its starting point to use it in ultrasupercritical pressure unit boiler for superheater and reheater. So it is very important to study the weldability, welding technology, compatibility of parent metal with welding and joint properties for the construction of ultra supercritical boiler, and it is also important for the maintenance and transformantion of present thermal power unit.In this paper, TIG welding process parameters for Super304H were determined according to theory analysis, and prepared the welded joint of Super304H by ERNiCrMo-3, ERNiCr-3 and YT304H welding wire. The mechanical properties, corrosion resistance, microstructure of three welded joint were respectively compared analysis according to mechanical property test, intergranular corrosiontest, stress corrosion test and microstructure observation.The results of the study showed that the welded joints room-temperature mechanical properties of Super304H made by ERNiCrMo-3 and ERNiCr-3 welding wire satisfy coherent technic standard, which equal to the welded joints properties made by the imported welding wire YT304H. The anti-intergranular erosion and anti-stress erosion properties using ERNiCrMo-3 is superior to that of using YT304H, and the anti-intergranular erosion and anti-stress erosion properties using ERNiCr-3 is inferior to that of using YT304H. The microstructure of weld is constituted by austenite and some dispersoid phase.According to the comparison, it is feasible to use nickel-based welding wire ERNiCrMo-3 to substitute the imported welding wire YT304H, and the anti-erosion property of the welded joint made by welding wire ERNiCr-3 is inferior to the welded joint made by welding wire YT304H.