ASTM B564 UNS N04400 Monel 400 nickel alloy flange as a commercially viable option for marine engineering purposes
From a human health perspective, the Nickel 400 Spectacle Blind Flange, which is used to clean, inspect or modify piping systems is effective in completely blocking or sealing off pressure vessels that could contain hydrofluoric acid, which again, is a contact poison.
Perhaps the best attribute of Monel 400 flanges is their ability to defy seawater corrosion. Uniquely, they offer resistance to rapidly moving seawater, which can erode other materials, though stagnant salt water situations can sometimes result in crevice and pitting corrosion. In addition, Monel 400 flanges prevent stress corrosion cracking and pitting in most fresh and industrial waters. Tempers improve the strength and the impact strength of the material. Though the high content of copper would indicate that the alloy would be attacked by acids, in a de-aerated condition, the Class 150 Monel 400 Rtj Flange shows resilience to both hydrochloric acid and hydrofluoric acid.