Heat-resistant steels dedicated for use above 800°C are mainly composed of chromium (for corrosion resistance purpose), nickel (for creep resistance) and iron. The most widely spread type of steels used for steam reforming applications, where high temperature and high pressure do apply, are from HP family.
HP family is composed of various steel grades composed of 25 wt% of chromium and 35 wt% of nickel. Initial HP grade, defined within ASTM A297 has supplanted HK grade decades ago. At that time, reformer tubes were thick (25 mm and even more) and even not internally machined. Since then, enhanced properties of HP grade – mainly higher creep resistance and microstructural stability over time – have greatly evolved thanks to research work of Manoir’s metallurgists.
Among the various innovations brought by Manoir we can list the addition of niobium (late 1960’s) and the micro-addition of titanium and zirconium (1980’S) which both resulted in increased carbides’ stability for dramatically increased creep resistance. In 2000’s, Manoir latest innovation regarding HP family was the introduction of Manaurite XMR, with an optimized metallurgy for precise control of carbides’ nucleation and precipitation. With now more than 10,000 catalyst tubes manufactured so far, Manaurite XMR has proved its efficiency. The high service flexibility it brings to hydrogen and syngas producers (possibility for higher throughput and/or higher service temperature and/or longer lifetime) is the main reason for its success.