Monel K500 Spacer Flanges has useful resistance to boiling sulfuric acid up to 40 % concentration, to 60 % concentration at 176 Degree F and in all concentrations to 150 Degree F. Stronger than 400, alloy K500 even retains this strength in corrosive conditions, resisting both pure and salt water, as well as non-oxidizing mineral acids, salts, alkalis, and sour gas. The exception being that Monel K500 fasteners can be more prone to stress-corrosion cracking in some environments than Monel 400.