Investigation on creep behaviours of centrifugal casting 27Cr44Ni5W3Al+MA alloy used as ethylene pyrolysis furnace tube at 1050°C

ABSTRACT

For centrifugal casting 27Cr44Ni5W3Al+MA alloy used in ethylene pyrolysis furnace, its creep behaviours at 1050°C are investigated. The results show that the alloy undergoes three stages during the creep tests under different stress levels ranging from 18 MPa to 30 MPa. The apparent stress index n of the alloy is 6.11, and the creep deformation mechanism is mainly dislocation climbing. During the creep test, the fishbone-like M₇C₃ inside eutectic precipitates in casted alloy gradually transform to massive M₂₃C₆ at the edge of the precipitate. Creep induced voids germinate and connect at the interface of austenite/M₂₃C₆ and austenite/Ni₃Al, the cavities expand along the M₂₃C₆ and Ni₃Al, forming micro-cracks and the alloy eventually cracks.

KEYWORDS:

• Ethylene pyrolysis furnace tube
• 27Cr44Ni5W3Al+MA
• high temperature creep
• carbide transition

Acknowledgments

This work was financially supported by National Natural Science Foundation of China (51901064), Youth Science and Technology Fund of Hefei General Machinery Research Institute Co., Ltd. (2020011727) and Technology development projects of Qingdao NPA Industry Co., Ltd. (2021030194).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The work was supported by the National Natural Science Foundation of China [51901064]; Technology development projects of Qingdao NPA Industry Co., Ltd. [2021030194]; Youth Science and Technology Fund of Hefei General Machinery Research Institute Co., Ltd. [2020011727].