Improved Oxidation, Carburization Resistance and Creep Strength of Ethylene Pyrolysis Furnace Tubes at 1100 °C Through Aluminum and Tungsten Alloying

Abstract The oxidation resistance, carburization resistance, and mechanical properties of ethylene pyrolysis furnace tube alloys modified by Al/Al-W alloying were comparatively investigated with conventional alloys using various microstructural characterization techniques and mechanical property testing methods. The Al-alloyed 29Cr44Ni4AlNb+microalloy (MA) exhibits superior oxidation and carburization resistance compared to conventional 25Cr35NiNb+MA and 35Cr45NiNb+MA alloys; however, its creep rupture life was significantly reduced. Further addition of W enhanced the solid solution strengthening effect, thereby improving high-temperature tensile properties and mitigating the detrimental impact of Al on creep performance. The creep rupture life of the Al/W-modified 27Cr44Ni5W3Al+MA alloy reached levels comparable to those of conventional alloys while retaining the beneficial effects of Al in improving oxidation and carburization resistance. Through alloying strategies, this study successfully achieved a balance between corrosion resistance and mechanical properties in ethylene pyrolysis furnace tube alloys, enabling them to withstand their harsh service conditions effectively.