Incoloy 800H Tube

 Incoloy 800H Tubes are choosen as convection tubes for use in cracking heaters based on its exceptional high-temperature strength, excellent creep resistance, good resistance to oxidation, carburization/intergranular corrosion, and corrosion from specific media, as well as sufficient structural stability and machinability. These properties collectively ensure the long-term, safe, and stable operation of the cracking heaters in high-temperature, corrosive environments.

Cracking heaters are core equipment in ethylene production in the petrochemical industry. The convection section of the piping primarily recovers heat from high-temperature flue gas to preheat the feedstock and superheat steam. These pipes must withstand multiple challenges, including high temperatures, corrosion, and pressure. Therefore, the material selection for these pipes is crucial.

 

Incoloy 800H was chosen for the convection tubes in cracking heaters primarily due to its advantages in high-temperature performance, corrosion resistance, and carburization resistance.

 

Incoloy 800H is a high-carbon, nickel-based, corrosion-resistant alloy with coarse grains and high creep strength, making it particularly suitable for operation in high-temperature environments exceeding 600°C (as cracking heaters require long-term operation at high temperatures).

 

Incoloy 800H's high nickel content (30-35%) provides excellent resistance to stress corrosion cracking.

 

The high chromium content (19-23%) provides resistance to pitting and crevice corrosion. At high temperatures, it forms a stable chromium oxide film, effectively protecting against oxidizing and carburizing environments. Cracking furnace flue gases may contain carburizing gases such as carbon monoxide, making carburization resistance crucial.

 

Chemical elements such as nickel and chromium help Incoloy 800H pipe resist corrosion from organic acids, oxidizing and non-oxidizing salts, making it well-suited for the various corrosive media encountered during the cracking process.

The Chemical Composition of Incoloy 800H Tube

Advantages of Incoloy 800H Tube

Property	Advantages of Incoloy 800H	Application in Convection Tubes
High-Temperature Strength	excellent creep and stress-rupture resistance	Withstands the impact of high-temperature cracking furnace flue gases, preventing pipe deformation or cracking under long-term high-temperature conditions.
Corrosion Resistance	Excellent resistance to oxidation, carburization, and sulfidation; resistant to nitric acid and organic acids	Resists corrosion from acidic media, water vapor, carbon dioxide mixtures, and sulfur-containing flue gases generated during the cracking process.
Microstructural Stability	Ti/Al stabilization treatment inhibits carbide precipitation and sensitization, reducing the risk of intergranular corrosion.	Ensures stable performance even after long-term use in the sensitive temperature range of 593-816°C.
Processing and Welding	Excellent hot workability and weldability	Facilitates fabrication, installation, and subsequent maintenance of convection tube module

However, Incoloy 800H tubes are not suitable for all cracking heating convection pipes because Incoloy 800H has limited corrosion resistance in sulfuric acid and hydrochloric acid and is not suitable for reducing strong acid environments. If the process medium contains high concentrations of sulfuric acid or hydrochloric acid, its corrosion rate needs to be evaluated or other more corrosion-resistant materials need to be considered.
 

The schedules of cold-worked, seamless nickel-iron chromium alloy pipe as given below are regularly available. Other schedules pls consulte us

Nominal Pipe Size	Outside Diameter	Nominal Wall Thickness,  Inches
		Schedule No. 5	Schedule No. 10	Schedule No. 40	Schedule No. 80
1/4	0.54	…	0.065	0.088	…
3/8	0.675	…	0.065	0.091	0.126
1/2	0.84	0.065	0.083	0.109	0.147
3/4	1.05	0.065	0.083	0.113	0.154
1	1.315	0.065	0.109	0.133	0.179
1 1/4	1.66	0.065	0.109	0.14	0.191
1 1/2	1.9	0.065	0.109	0.145	0.2
2	2.375	0.065	0.109	0.154	0.218
2 1/2	2.875	0.083	0.12	0.203	0.276
3	3.5	0.083	0.12	0.216	0.3
3 1/2	4	0.083	0.12	0.226	0.318
4	4.5	0.083	0.12	0.237	0.337
5	5.563	…	…	0.258	…
6	6.625	…	…	0.28	…

For more information on the dimensions, production, heat treatment, and other aspects of Incoloy 800H pipes, please refer to the ASTM B407 standard: https://www.htpipe.com/d/files/pipe-material-standard/astm-b407.pdf


HT PIPE is a metal company specializing in pipes for the petrochemical industry. If you have any inquiry, please contact us.