In modern chemical and petroleum industries, seamless steel pipes serve as a crucial basic material, undertaking the important task of transporting high-temperature, high-pressure, and corrosive media. Their performance directly affects the safe operation and production efficiency of the plants.
First, the material characteristics and core advantages of seamless steel pipes for petrochemical and chemical plants.
Due to their seamless, integrated structure, seamless steel pipes are significantly superior to welded steel pipes in terms of pressure resistance and sealing performance. Taking seamless steel pipes used in petroleum cracking as an example, which need to withstand temperatures above 450℃ and hydrogen sulfide corrosion, Cr-Mo alloy steel (such as 15CrMoG) or austenitic stainless steel (such as 0Cr18Ni9) is typically used. These steel pipes must pass the GB 5310 standard “Seamless Steel Pipes for High-Pressure Boilers,” with a tensile strength of at least 415 MPa and a yield strength of not less than 205 MPa.
Second, Typical Application Scenarios and Technical Parameters of Seamless Steel Pipes for Petrochemical and Chemical Plants.
1. Oil Refining Units: The oil transfer line of atmospheric and vacuum distillation units uses large-diameter seamless pipes (Φ219mm~Φ813mm) with operating pressures up to 4MPa; the regenerator cyclone separator of catalytic cracking units requires 310S heat-resistant stainless steel pipes to withstand the scouring of flue gas at 900℃.
2. Ethylene Cracking: Data shows that the furnace tubes in the convection section of cracking furnaces mostly use HP40Nb centrifugal cast pipes, with a chromium-nickel content of 25Cr-35Ni, and a creep rupture strength of over 30MPa at 1000℃.
3. Coal Gasification Furnaces: The slag conveying pipes of Shell coal gasification units need to possess both wear resistance and corrosion resistance, often using bimetallic composite pipes with an inner layer of high-chromium cast iron (HRC≥58) and an outer layer of carbon steel pressure-bearing material.
It is worth noting that different media have different requirements for materials. The article states that when handling media containing chloride ions, super austenitic stainless steel (such as 254SMO) with a PREN (pitting resistance equivalent) value greater than 40 is required; while liquefied natural gas (LNG) cryogenic pipelines require 9% nickel steel, which maintains good toughness even at -196℃.
Third, a comparison of domestic and international standard systems for seamless steel pipes used in petrochemical and chemical plants.
Steel pipes used in my country’s petrochemical industry mainly follow standards such as GB/T 8163 (fluid transportation) and GB 9948 (petroleum cracking), which are benchmarked against ASTM A335 (American standard) and EN 10216 (European standard). Taking P91 steel pipe as an example, there is a significant difference in impact energy requirements between GB 5310 and ASME SA335: the Chinese standard requires a transverse impact energy ≥40J (20℃), while the American standard requires a longitudinal impact energy ≥54J.
Fourth, Key Quality Control Nodes for Seamless Steel Pipes Used in Petrochemical and Chemical Plants.
1. Manufacturing Process: Hot-rolled pipes require a final rolling temperature 50°C above Ar3 to avoid banded structures; cold-drawn pipes require intermediate annealing to eliminate work hardening.
2. Testing Technology: In addition to conventional ultrasonic testing, large-diameter thick-walled pipes require TOFD (Time-of-Flight Diffraction) to detect delamination defects; high-temperature service steel pipes should undergo intergranular corrosion testing (e.g., GB/T 4334 E method).
3. On-site Installation: The hydraulic test pressure should be 1.5 times the design pressure, and the pressure holding time should be no less than 10 minutes. A case study from a petrochemical project shows that excessive chloride ion content (>25 ppm) in the test water led to stress corrosion cracking in austenitic steel pipes.
Fifth, Technological Innovation and Development Trends of Seamless Steel Pipes for Petrochemical and Chemical Plants.
1. Material Upgrade: Sinopec Engineering Research Institute is promoting TP347HFG fine-grained stainless steel, which has a 20% higher creep strength than conventional TP347 and is suitable for ultra-supercritical conditions at 700℃.
2. Composite Technology: Titanium/steel composite pipes prepared by explosive bonding and hot rolling have a 60% lower cost than pure titanium pipes and have been successfully applied in acetic acid plants.
3. Intelligent Monitoring: Online corrosion monitoring systems based on fiber optic sensors can achieve early warning of wall thickness changes with an accuracy of 0.1mm. After application in a refinery, the maintenance cycle was extended from 3 years to 5 years.
With the advancement of the “dual carbon” goal, steel pipes for green hydrogen plants face new challenges. Existing research indicates that hydrogen-bearing pipelines require the development of new oxide dispersion reinforced steel (ODS), whose hydrogen permeability can be reduced by two orders of magnitude compared to traditional steel. At the same time, digital twin technology is being promoted and applied in the entire life cycle management of pipelines, using 3D modeling to predict remaining life in real time, providing data support for preventative maintenance.
The technological evolution of seamless steel pipes for petrochemical applications has always resonated with industrial demands. From the microscopic control of materials science to the macroscopic performance optimization for engineering applications, every detail embodies the wisdom of modern manufacturing. In the future, with breakthroughs in deep processing technology and the penetration of intelligent technologies, this traditional field will be revitalized, continuously safeguarding the safe and efficient operation of the energy and chemical industry.
Post time: Nov-21-2025