Industry Applications

Allianz Steel Group

Superalloy Tubes,Austenitic Stainless Tubes,Duplex Stainless Tubes

Requirements for Stainless Steel Performance in Petrochemical Reaction Units

Date:2025-08-31

Device Type	Application Area	Application Environment	Material selection requirements	Tube Selection
Hydrocracking unit	Reactor outlet pipe	High temperature (above 400℃), high pressure (10-15MPa)	High temperature strength, hydrogen corrosion resistance, and sulfide stress corrosion cracking (SSCC) resistance	TP347H Large Diameter Thick Wall Seamless Pipe
	High-pressure heat exchanger tube bundle	High concentration of Cl⁻ and residual H₂S on the cooling water side	Excellent resistance to chloride stress corrosion cracking (SCC)	Duplex stainless steel (such as 2205)
	Heating furnace tubes	High-temperature flue gas, high-pressure medium in the pipe	High temperature resistance, antioxidant	TP321H, TP347H
Ethylene cracker	Cracking furnace tubes	Extremely high temperature (above 800°C), carburizing environment	Extremely high resistance to high temperature carburization, creep and oxidation	HP series heat-resistant alloy cast steel pipes (such as HP40)
	Rapid cooling heat exchanger pipes	High-temperature cracking gas, large temperature changes	Heat resistance, thermal fatigue resistance, corrosion resistance	Duplex stainless steel/special alloys
	High temperature steam pipes	High temperature and high pressure steam (500-600℃)	Excellent high temperature strength and long-lasting strength	TP321H, TP347H
Atmospheric and vacuum devices	Top condensation system	Low temperature (-120°C) HCl-H₂S-H₂O environment	Resistant to pitting corrosion and SCC caused by wet H₂S and Cl⁻, superior to carbon steel and ordinary austenitic stainless steel	Duplex stainless steel (such as 2205)
Catalytic Cracking Unit	Absorption and desorption system	HCN-H₂S-H₂O corrosive environment	Sulfide stress corrosion resistance	Duplex stainless steel (such as 18-5Mo)

When selecting stainless steel pipe for petrochemical plants, the following considerations are crucial
1. The concentration and temperature of corrosive media such as H₂S, Cl⁻, and COOH (carboxylic acid) are the primary factors in material selection. For example, Cl⁻ environments are the number one cause of stress corrosion cracking in austenitic stainless steel.
2. Temperature and pressure determine the required strength grade of the material (e.g., whether to select H-grade stainless steel), as well as the material's heat resistance.
3. Processing and manufacturing processes: Weldability is crucial. For example, when welding duplex stainless steel, strict control of heat input and interpass temperature is required to ensure a balanced phase ratio and good performance in the welded joint. The choice of cold working and heat treatment also significantly affects the material's corrosion resistance.
4. Standards and specifications: Steel must comply with industry specifications and international standards (e.g., ASTM, NACE MR0175/ISO 15156).