In service embrittlement of cast 20Cr32Ni1Nb components used in steam reformer applications

Severe embrittlement has been experienced in a number of cast manifold components. This has manifested itself as cracking at tee to manifold connections. Attempts to weld repair proved futile leading to concern about the integrity of the entire system. This experience contrasts with similar components that have successfully remained in service for many years. The paper describes the investigations into these failures and laboratory investigations into the properties of cast 20Cr32Ni1Nb alloys. Results indicate that variations in alloy chemistry within the stated allowable range are sufficient to cause embrittlement