09CrCuSb welded steel pipe is a low-alloy steel with excellent resistance to sulfuric acid dew-point corrosion. It is widely used in flue gas desulfurization systems in the power, metallurgy, and chemical industries. Through a rational alloy design, this material incorporates elements such as Cr, Cu, and Sb on a conventional carbon steel basis, resulting in exceptional corrosion resistance in sulfur-containing flue gas environments, making it a key material in environmental protection equipment.

First, Material Properties and Chemical Composition Analysis of 09CrCuSb Welded Steel Pipe.
The chemical composition of 09CrCuSb welded steel pipe is specifically formulated, with a chromium content controlled between 0.50% and 1.20%, a copper content between 0.25% and 0.45%, and an antimony content between 0.05% and 0.12%. This alloy combination forms a dense protective film on the steel surface, effectively blocking corrosion from corrosive media. Compared to ordinary Q235 steel, the corrosion rate in a 50% H₂SO₄ solution at 60°C can be reduced by over 80%, extending its service life by 3-5 times. This material also exhibits excellent weldability and processability, with a yield strength of≥295 MPa, a tensile strength of≥390 MPa, and an elongation of≥22%, fully meeting the mechanical performance requirements of structural components.

Second, Key Technologies in the Production Process of 09CrCuSb Welded Steel Pipes.
The production of high-quality 09CrCuSb welded steel pipes involves several key technologies: first, steel strip pretreatment, employing pickling and phosphating to ensure surface cleanliness; second, high-frequency welding process control, requiring precise control of the welding temperature between 1350-1450°C, and the use of dual-gas shielding (80% Ar + 20% CO₂) to ensure weld quality; and finally, heat treatment, requiring post-weld normalizing at 880°C to eliminate weld stress. Currently, mainstream domestic manufacturers use the JCOE forming process to produce various specifications with diameters ranging from 219 to 3000 mm and wall thicknesses from 6 to 40 mm. The weld ultrasonic flaw detection pass rate reaches over 99.5%.

Third, Current Industry Application Status of 09CrCuSb Welded Steel Pipes
In the power industry, 09CrCuSb welded steel pipes are primarily used in key areas such as the spray layer of desulfurization towers and flue gas reheaters in coal-fired power plants. A power plant renovation case study shows that the use of this material has extended equipment maintenance cycles from one year to four years. In the metallurgical industry, it is used in high-temperature, high-humidity, and sulfur-containing environments such as sintering machine heads, electrostatic precipitators, and coke oven gas purification systems. Notably, in the chemical industry, this material has also been successfully used in the manufacture of dilute sulfuric acid storage tanks, replacing traditional 316L stainless steel and reducing equipment costs by over 40%. According to a Baidu Baijiahao industry report, market demand for 09CrCuSb welded steel pipes in my country will exceed 500,000 tons in 2024, with an annual growth rate of approximately 15%.

Fourth, the quality inspection standard system for 09CrCuSb welded steel pipes.
This product complies with the GB/T2975-2018 "Steel Plate and Strip Resistant to Sulfuric Acid Dew Point Corrosion" standard and meets the requirements of the NB/T47003.1-2019 "Technical Specification for Boiler Steel Structure Manufacturing." Key testing items include: intergranular corrosion test (according to GB/T4334), copper sulfate drop test (corrosion rate ≤ 3.5 g/m²·h), and weld X-ray inspection (Level II qualified). Third-party testing data show that the annual corrosion rate of high-quality 09CrCuSb welded steel pipes in simulated flue gas condensate (pH = 1.5) does not exceed 0.25 mm, far superior to the 2.0 mm annual corrosion rate of ordinary carbon steel.

Fifth, a market guide for purchasing 09CrCuSb welded steel pipes.
Consumers should pay attention to the following key points when purchasing: First, verify whether the manufacturer has a Special Equipment Manufacturing License (TS certification); second, require the most recent third-party test report; and third, pay attention to the product's actual alloy content, especially the Sb content. The current mainstream market price range is 6,800-8,500 yuan/ton, significantly lower than similar imported products (approximately 12,000 yuan/ton). It is recommended to prioritize manufacturers with complete heat treatment equipment and avoid purchasing welded steel pipes that have not undergone normalizing.

Sixth, Installation and Usage Precautions
Engineering practice shows that proper installation directly affects the performance of 09CrCuSb welded steel pipes: E309L series welding rods should be used during welding, and the interpass temperature should be controlled below 150°C. The pipe support spacing should be 20% shorter than that of ordinary carbon steel pipes to prevent vibration corrosion. During system shutdown, accumulated fluids should be drained promptly to avoid localized high concentrations. A case study of a desulfurization project demonstrates that the use of cathodic protection (protection potential -0.85V) in conjunction with 09CrCuSb material can further extend equipment life to over eight years.

Seventh, Future Development Trends of 09CrCuSb Welded Steel Pipes
With increasingly stringent environmental standards, 09CrCuSb welded steel pipe technology continues to innovate: the new generation of products improves corrosion resistance by 30% through the addition of trace rare earth elements; the application of intelligent manufacturing technology enables online, real-time monitoring of weld quality; and modular design promotes the formation of a standardized product system. Industry experts predict that with the advancement of carbon peak policies, the application of this product in emerging sectors such as waste incineration, power generation, and biomass power plants will experience explosive growth from 2025 to 2030.

In summary, as an environmentally friendly material independently developed in my country, 09CrCuSb welded steel pipe has established a complete production and application system through over two decades of technological accumulation. When selecting, users need to combine specific working conditions and conduct a comprehensive evaluation from multiple dimensions, such as material properties, manufacturing process, and testing standards, to fully utilize its corrosion resistance advantages and provide long-term and reliable material guarantees for environmental protection facilities.