Community Research and Development Information Service - CORDIS


G-X 40 NiCrNb 35 25 (also known as Manaurite 36X or HP40Nb) is a centrifugal casting alloy mainly used in the petrochemical industry at temperatures ranging between 950 C and 1100 C. Precipitation-hardened alloys are particularly prone to changes in their characteristics under these conditions, due to a coarsening of the precipitates. It is observed that storage enhances the properties of the material. The possibility of using thermal pre-treatment to improve creep behaviour has been investigated. 40mm x 8mm samples of the material were subjected to various temperature/time treatments. One batch was kept at 1000 C for 8000h. Samples in a second batch were kept at 1050 C/3h, 1050 C/65h and 1100 C/65h. Their behaviour under creep-inducing stress at 1000 C was subsequently observed. Results showed that storage and thermal pre-ageing improve the creep characteristics of the material, mainly due to an increase in ductility. Since storage leads to coarser carbides, which occupy grain boundaries to a considerable extent, increased ductility was an unexpected result. With the help of electron microscope data it was, however, possible to put forward a likely explanation.

Additional information

Authors: GUTTMANN V, JRC Petten (NL);SCHOENHERR H, JRC Petten (NL)
Bibliographic Reference: Paper presented: Zwoelfte Vortragsveranstaltung, Duesseldorf (DE), December 1, 1989
Availability: Available from (1) as Paper DE 35144 ORA
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