Steel alloys containing more than 20% chromium produce a protective, sustainable surface scale when exposed to high temperatures in oxidising atmospheres up to 1100 degrees C. When nickel and carbon are added to these alloys, a series of heat resisting alloys is produced to perform in an array of high temperature applications.

Increased nickel content progressively stabilises austenite in heat resisting steels, from a duplex structure especially designed for sulphurous environments (R80), through alloys with measured ferrite/austenite ratios (R81,R83), to fully austenitic alloys (R84, R85).

By adjusting nickel, chromium and carbon content and including additions of rare earth elements, niobium and tungsten, castings can be manufactured to withstand high temperature thermal cycling, carburising and high load environments. In more severe applications, a series of grades with substantially increased nickel contents are used (R87,R88). Generally, these super alloys contain additions of one or a combination of rare earths, niobium, tungsten and cobalt (R87Nb, R88Nb,R89). This produces an alloy that is able to absorb considerable amounts of carbon over long periods without significant embrittlement.


R71 AS 2074-L5E, A217-C5
R72 AS 2074-H2A, A217-C12
R78 A297-HC
R80 A297-HE
R81 A297-HF
R82 A297-HK
R83 AS 2074-H8B, A297-HH
R83 LC AS 2074-H8A A351-CH20
R84 AS 2074-H8E-2, A297-HK
R84 LC AS 2074-H8E-1, A351-CK20
R84 HC AS 2074-H8E-2, A351-HK40
R85 A297-HL
R86 Ingersoll Rand Spec, IR 519
R87 A297-HP
R88 A297-HU
R88 Nb Q.C. Special Alloy
20/20W Q.C. Special Alloy
15/35 A297-HT
20/25 A297-HN
INC601 Incoloy 601
INC800HT Incoloy 800HT
INC825 Incoloy 825
INC625 Incoloy 625


R89 Manurite 35K or Supertherm
Q99 UMCO 50,51
Q100 Stellite 1 or 3