SuperElso® 500 HR (SE 500 HR, "Hydrogen Resistant") is a 500MPa yield strength quenched and tempered steel adapted for pressure equipment operating under sour service condition. It is designed to meet the requirements of NACE Standard MR0175, with a maximum hardness of 22 HRC in the heat-affected zone (HAZ) after post-weld heat treatment (PWHT).

SuperElso® 500 HR is manufactured via the electric arc furnace with dephosphorisation, ladle refining and vacuum degassing to provide a reproducible, clean steel. The use of special steelmaking practice imparting high steel cleanliness, along with a carefully adapted chemistry and a uniform structure provides SuperElso® 500 HR with excellent resistance to wet H2S cracking, including SSC, HIC and SOHIC.

The low carbon content of SuperElso® 500 HR limits the HAZ hardness after welding and also improves weldability. This steel displays excellent toughness, with a low transition temperature (-60°C/-76°F).

This steel is particularly suitable for pressure equipment in wet H2S service in the offshore oil and gas industry, where its high strength allows significant weight and cost reductions.