09CrCuSb Seamless Steel Pipes For Economizer is a special alloy tube designed for resistance to low-temperature sulfuric acid dew point corrosion in high-sulfur flue gas environments. It is widely used in economizers, air preheaters, and low-temperature heating surfaces of coal-fired and oil-fired boilers. The material is manufactured according to GB/T 150.2, GB/T 3087, or GB/T 5310 standards.
The steel contains Cr (0.70–1.20%), Cu (0.25–0.45%), and Sb (0.10–0.20%), which help form a dense protective passive film on the surface, significantly improving corrosion resistance. Its resistance to sulfuric acid dew point corrosion is 3–5 times higher than that of ordinary carbon steel such as 20G.
It performs well under internal pressure, flue gas erosion, and thermal cycling, with a service temperature range up to about 400°C. Compared with stainless steel, it can reduce material cost by up to 50%.
We supply 09CrCuSb seamless boiler tubes in OD Φ32–51 mm and WT 3–5 mm, with lengths of 6–12 meters or customized. All pipes are fully tested by UT, ET, and hydrostatic testing to ensure reliable performance in power plant boiler applications.
09CrCuSb Seamless Steel Pipes Specification
| Item | Specifications |
| Product Name | 09CrCuSb Seamless Steel Pipes for Economizer (ND Steel Pipe) |
| Material | 09CrCuSb (ND Steel) |
| Standard | GB/T 150.2, GB/T 3087, GB/T 5310, etc. |
| Outer Diameter (OD) | Φ32mm - Φ51mm (Common specifications for economizers) |
| Wall Thickness (WT) | 3.0mm - 5.0mm |
| Length | Fixed length: 6m - 12m, or customized length according to design requirements for bent pipes and serpentine tube bundles. |
| Tolerance | According to standard |
| Testing & Inspection | Ultrasonic Testing (UT), Eddy Current Testing (ET), Hydrostatic Test, etc. |
| Quality Management | ISO9001, CE, Third-Party Testing / Inspection, Certifications applicable to buyers' countries |
| Lead Time | Depends on specifications, quantity, etc. |
| Package | Standard seaworthy package, or as required |
We can supply 09CrCuSb seamless steel pipes in various sizes and wall thicknesses. Please contact us if you require customized dimensions for your economizer project.
Contact now to get the the 09CrCuSb seamless steel pipes Stock List
09CrCuSb (ND Steel) Seamless Boiler Tube Complete Dimensional Tolerance Table
| Item | Specification | Tolerance / Requirement |
|---|---|---|
| Outside Diameter (OD) ≤ 30 mm | ±0.30 mm | |
| Outside Diameter (OD) 30 – 50 mm | ±0.40 mm | |
| Outside Diameter (OD) 50 – 70 mm | ±0.60 mm | |
| Outside Diameter (OD) 70 – 100 mm | ±0.80 mm | |
| Outside Diameter (OD) > 100 mm | ±1% of OD | |
| Wall Thickness (WT) ≤ 4 mm | ±12.5% | |
| Wall Thickness (WT) 4 – 10 mm | ±10% | |
| Wall Thickness (WT) > 10 mm | ±8% | |
| Length (Fixed Length ≤ 12 m) | +10 / 0 mm | |
| Length (Random Length) | 3000 – 12000 mm (or as per contract) | |
| Precision Cut Length | ±5 mm (or tighter upon request) | |
| Straightness (≤ 6 m) | ≤ 1.5 mm per meter | |
| Straightness (> 6 m) | ≤ 2.0 mm per meter | |
| Standard | GB/T 3087 / GB/T 5310 (or equivalent) | Applicable standards |
| Application | Economizer / Air Preheater / Low-temperature heating surface | Boiler systems |
09CrCuSb Chemical Composition
| 09CrCuSb Chemical Composition (%) | |||||||
| C | Si | Mn | P | S | Cr | Cu | Sb |
| ≤0.12 | 0.20-0.40 | 0.35-0.65 | ≤0.030 | ≤0.020 | 0.70-1.10 | 0.25-0.45 | 0.04-0.10 |
09CrCuSb Tubes Mechanical Property
| 09CrCuSb Tubes Mechanical properties At RT (EN ISO 6892-1) |
|||
| Tensile | Yield | Elongation | Corrosion resistance rate |
| Strength Rm (MPa) | Strength ReL (MPa) | A (%) | mg/cm².h |
| 390-550 | ≥245 | ≥25 | 7.4 |
Application: 09CrCuSb seamless tube in Boiler Economizer Systems
Economizer serpentine tube bundle:
As the core material of serpentine heating surfaces, it exhibits excellent cold bending performance (no cracks in 180° bending test), making it fully suitable for small bend radius pipe forming.
With a carbon equivalent of ≤ 0.38%, it requires no preheating during welding, and the weld joint achieves strength equivalent to the base metal, ensuring no leakage under high-temperature and high-pressure water circulation conditions.
Low-temperature heating surface protection:
It is specifically installed in the cold end of the economizer (the high-risk condensation zone between feedwater inlet and flue gas outlet) as the first barrier against dilute sulfuric acid corrosion. Its acid resistance is 3–5 times higher than that of ordinary carbon steel, effectively preventing premature wall perforation and tube failure.
Tube liner and support structures:
In addition to tubes, ND steel plates are also used to manufacture fixed supports, anti-wear plates, and baffle plates. Compared with conventional carbon steel, which typically lasts only 1.5–2 years, ND steel can extend the overall corrosion protection service life by 2–3 times (up to 5–8 years), significantly increasing maintenance intervals and reducing overhaul frequency.
Can 09CrCuSb replace stainless steel (like 304 or 316L) to save costs?
In specific low-temperature, dilute sulfuric acid dew-point environments, 09CrCuSb actually outperforms standard austenitic stainless steels, which are prone to localized pitting and stress corrosion cracking in acidic, high-chloride environments.
Switching to 09CrCuSb can slash your material procurement costs by 50% to 70% compared to stainless steel while offering equal or better service life.
| Material | 0.5% H₂SO₄ Corrosion Rate (mm/year) | Atmospheric Corrosion Rate (mm/year, industrial environment) | Salt Spray Test (h to red rust) | Typical Passive Film Stability | Relative Corrosion Resistance Index* |
|---|---|---|---|---|---|
| 09CrCuSb (ND Steel) | 0.02 – 0.05 | 0.10 – 0.30 | 200 – 500 h | Stable in SO₂ / acidic condensate | 3.0 – 5.0 × carbon steel |
| Weathering Steel (Corten A/B) | 0.20 – 0.60 | 0.02 – 0.10 (after patina formation) | 48 – 120 h | Stable only in dry/wet atmospheric cycles | 2.0 – 4.0 × carbon steel |
| Stainless Steel 304 | 0.01 – 0.03 | <0.01 | >1000 h | Very stable (Cr₂O₃ passive layer) | 8.0 – 12.0 × carbon steel |
| Stainless Steel 316 | 0.005 – 0.02 | <0.01 | >1500 h | Highly stable (Mo-enhanced passive film) | 10.0 – 20.0 × carbon steel |
| Carbon Steel (20G reference) | 0.10 – 0.30 | 0.10 – 0.50 | 24 – 48 h | No stable passive film | 1.0 (baseline) |
Is 09CrCuSb easy to bend and process into serpentine tube bundles?
09CrCuSb features a low carbon equivalent (Ceq≤0.38%), delivering excellent cold-bending and ductility performance. It passes the standard D=2a (bending mandrel diameter is twice the pipe thickness) 180° bend test without any surface cracking, making it ideal for high-density, small-radius serpentine tube bending.
In addition to supplying high-quality 09CrCuSb (ND Steel) boiler economizer tubes, we also offer the following value-added processing services:
• Tube Bending: CNC cold bending for U-bends, serpentine tubes, and custom boiler tube assemblies according to customer drawings.
• Tube End Processing: Precision cutting, beveling, chamfering, and end preparation for efficient on-site welding and installation.
• Welding & Fabrication: Custom welding and assembly of economizer tube panels, tube bundles, and boiler components.
• Surface Protection: Shot blasting, anti-rust oil coating, and protective end caps to prevent corrosion during storage and transportation.
Our technical and certification requirements
Applicable standards: Manufactured in accordance with GB/T 3087, GB/T 5310, and GB/T 150.2 requirements for boiler and pressure-bearing components.
Delivery condition: Hot-finished or cold-drawn seamless tubes, supplied in normalized condition with clean internal and external surfaces.
Corrosion resistance requirement: The material shall provide excellent resistance to sulfuric acid dew point corrosion and exhibit a corrosion resistance 3–5 times higher than conventional carbon steel in low-temperature flue gas environments.
Inspection requirements: All tubes shall undergo hydrostatic testing, ultrasonic testing (UT), and/or eddy current testing (ET) to ensure freedom from harmful defects.
Forming and welding requirements: Suitable for cold bending and serpentine tube fabrication. Welding can be performed without preheating under normal conditions, and the weld metal shall achieve mechanical properties comparable to the parent material.
Documentation requirements: EN 10204 3.1 Mill Test Certificate (MTC) shall be supplied, including heat number, chemical composition, mechanical properties, dimensions, and inspection records for full traceability.
09CrCuSb boiler tubes are supplied with waterproof, anti-corrosion packaging and protected pipe ends to prevent damage during transit. Global shipping is available by container or truck, with standard delivery times of 7–15 days.
