Corrosion resistance:Excellent resistance to pitting and stress corrosion cracking in chlorine-containing environments. Pitting resistance in accordance with ASTM G48-A better than 40 °C.
Isoarc 2507 is intended for welding super duplex alloy such as SAF 2507 (UNS 32750), UNS 327760, UNS 32550 and UNS 31260. It can also be used for welding duplex, type 2209, if extra high corrosion resistance is required, e.g. in root runs in tubes. Isoarc 2507 produces a ferritic-austenitic weld metal. The higher content of Cr, Ni, Mo and N compared to 2205 provides excellent mechanical and corrosion properties.
The weldability of Isoarc 2507 is excellent. However, super duplex steels are somewhat more difficult to weld compared to austenitic steels such as 316L, mainly with respect to fluidity and penetraction into the metals. To utilise the good properties of a duplex steel it is of utmost importance to obtain a good ferrite content in the weld . This is best achieved by welding with sufficient root gap (2-2.5mm), using the right amount of filler metal and welding with a controlled heat input. 2507 should be welded with a heat input not exceeding 1.5kJ/mm and by keeping the interpass temperature at a maximum of 100 C. Welding without filler metal (TIG-dressing) is not advisable, as the ferrite content will increase drastically, which will have a negative effect on both mechanical and corrosion properties.