Q: I have down hole application containing sour gas and high chloride levels. The temperature the bolts are exposed to is around 150F and I’m having trouble with cracking. I tried Super Duplex 2507 but am still having issues. Any ideas?

A: Super Duplex 2507 does provide good resistance to stress corrosion cracking, pitting and crevice corrosion in warm chloride environments to around 570 F, but I think in combination with the sour gas, and perhaps stress of your operation, it may need something more robust. A great material for a combination of sour gas, chloride, high strength and temperatures to consider is Incoloy 925. Down-hole oil & gas rely on this material for its excellent resistance to sulfide stress cracking and stress-corrosion cracking in H2S environments. It has a high operating temperature of 1200°F which is well beyond what you need. It is also has a much higher yield strength (120 ksi) compared to Super Duplex 2507 bolts of 82ksi.