Core Material (Backing)
Core Material (Backing): ASME SA-210 Gr.C / EN10216-2 (carbon steel – medium carbon, high tensile strength for boiler service)
Cladding (CRA liner): TP304L (1.4306) – low carbon austenitic stainless steel, excellent weldability, good resistance to oxidation and mild acidic corrosion
Size Range: OD 25 – 168 mm; Core wall thickness 3 – 15 mm; Cladding thickness 1.5 – 3.5 mm; single length up to 15 m
Process: Hot extrusion → cold finishing → heat treatment → pickling. Fully seamless, no longitudinal weld. Metallurgical bond shear strength ≥300 MPa.
Standards: ASME Section II Part A (SA-210/SA-213), EN10216-2, EN12952-2, ASTM E213, ISO 10893-10.
Testing: 100% hydrostatic, ultrasonic per ASTM E213/ISO 10893-10, tensile, flattening, hardness. EN 10204 Type 3.1 certificate (3.2 optional).
Applications: Boiler water walls, economizers, low-temperature superheaters, feedwater heaters, shell & tube heat exchangers (tube side corrosive), waste heat recovery with mild acidic condensate.
Womic Steel supplies SA-210 Gr.C / 304L seamless clad pipe combining the strength of carbon steel with the corrosion resistance of 304L. Cost-effective alternative to solid stainless steel. Ready for power plant, industrial boiler, and heat exchanger projects. Contact us for full datasheet and project specific offer.
1. Why Choose SA 210 Gr.C / 304L Clad Pipe
Problem: Carbon steel (SA 210 Gr.C) has excellent strength and low cost but suffers from general corrosion, pitting, and scale buildup when exposed to certain water chemistries, acidic condensate, or oxidizing conditions. Solid 304L stainless steel solves corrosion but is significantly more expensive and may be over specified for the required pressure rating.
Solution: SA 210 Gr.C / 304L clad pipe uses a thick, strong carbon steel core to contain pressure, while a thin (1.5–3.5 mm) inner layer of 304L provides the necessary corrosion resistance. The hot extrusion process creates a true metallurgical bond, eliminating any risk of liner collapse or crevice corrosion at the interface. This hybrid construction cuts material cost by 40 50% compared to solid 304L pipe while offering nearly equivalent corrosion protection inside.
Typical driver: Boiler water wall tubes that see demineralized water with occasional pH excursions or oxygen ingress; economizers where dissolved oxygen and low pH cause carbon steel to corrode; heat exchangers handling mildly aggressive cooling water (low chlorides). SA 210 Gr.C is chosen for its higher strength compared to Gr.A or Gr.B, allowing thinner walls and lighter weight for the same pressure rating.
2. Material Specifications – SA 210 Gr.C (Core) & 304L (Cladding)
2.1 Chemical Composition
| Element | SA-210 Gr.C (Core, % max) | 304L (Cladding, % max) |
| Carbon (C) | 0.35 | 0.030 |
| Manganese (Mn) | 0.29-1.06 | 2.00 |
| Phosphorus (P) | 0.035 | 0.045 |
| Sulfur (S) | 0.035 | 0.030 |
| Silicon (Si) | 0.10 min (for deoxidization) | 0.75 |
| Chromium (Cr) | — | 18.0 – 20.0 |
| Nickel (Ni) | — | 8.0 – 11.0 |
| Molybdenum (Mo) | — | — |
Core SA-210 Gr.C is a carbon steel without intentional alloy additions; strength comes from carbon and manganese. 304L is low carbon to prevent sensitization during welding.
2.2 Mechanical Properties (Room Temperature)
| Property | SA-210 Gr.C (Core) | 304L (Cladding) |
| Yield Strength (min, MPa) | 245 | 170 |
| Tensile Strength (min, MPa) | 485 | 485 |
| Elongation (min, %) | 22 | 35 |
| Hardness (max, HB) | 179 | 201 |
| Impact (Charpy) | Not required typically | Not required |
Note: For elevated temperatures, SA-210 Gr.C retains about 40-50% of room temperature yield at 400°C. Design per ASME Section I or EN12952.
2.3 Bond Interface
| Property | Requirement |
| Bond type | Metallurgical (atomic diffusion) |
| Shear strength | ≥300 MPa (per push out test) |
| UT bond integrity | No disbond >50 mm; total disbond <2% of area |
2.4 Dimensional Range
| OD (mm) | Core WT (mm) | Cladding WT (mm) | Max Length (m) |
| 25 – 50 | 3.0 – 6.0 | 1.5 – 2.0 | 15 |
| 50 – 80 | 4.0 – 8.0 | 1.8 – 2.2 | 15 |
| 80 – 120 | 5.0 – 12.0 | 2.0 – 2.5 | 15 |
| 120 – 168 | 6.0 – 15.0 | 2.2 – 3.5 | 12 |
Custom dimensions available; larger OD may require welded clad pipe (JCOE) – contact for details.
3. Manufacturing Process – Hot Extrusion, Cold Finishing, Heat Treatment & Pickling
The entire process is designed to ensure a clean, defect-free metallurgical bond and precise dimensions.
| Step | Description |
| 1. Composite billet preparation | SA-210 Gr.C billet is bored to receive a 304L tube. Surfaces are cleaned and the assembly is evacuated and sealed. |
| 2. Hot extrusion | Composite billet heated to 1150 1200°C, extruded through a die at reduction ratio ≥8:1. The extreme pressure creates a solid-state diffusion bond. |
| 3. Cold finishing | Extruded tube is cold drawn or pilgered to final OD and wall thickness. Multiple passes with intermediate annealing refine grain structure. |
| 4. Heat treatment | Normalizing (880-920°C) + tempering (600-650°C) for the SA 210 core; the 304L cladding receives solution annealing during the same cycle. |
| 5. Pickling & passivation | Tube is immersed in nitric hydrofluoric acid to remove scale. The stainless surface becomes passive (chromium oxide film). |
| 6. Straightening & cutting | Precision straightening; cut to ordered length with end deburring. |
| 7. NDT & testing | Full ultrasonic and hydrostatic testing per Section 4. |
| 8. End finishing & packaging | Bevel if specified; plastic caps and bundling for shipment. |
Quality checkpoints: Temperature records during extrusion and heat treatment; chemistry and tensile verification per heat; dimensional check after cold finishing; pickling solution analysis.
The above dimensions are based on a real customer inquiry. Womic Steel can produce these combinations as standard or adjust dimensions and tolerances according to customer drawings.
4. Inspection & Testing – Following ASME & EN Requirements
All tubes meet or exceed the requirements of ASME SA-450, SA-210, SA-213, EN12952-2, and the customer’s call for ASTM E213 and ISO 10893-10.
| Test | Standard | Scope | Acceptance |
| Ultrasonic (longitudinal imperfections) | ASTM E213 / ISO 10893-10 | 100% speed-controlled scan | No rejectable echo; any flagged defect recorded |
| Hydrostatic test | ASME SA-450 / EN12952-2 | Each tube to ≥1.5× design pressure (min 5s hold) | No leakage, no permanent dilation |
| Tensile test (core) | SA-210 / EN10216-2 | Per heat / batch | YS≥245 MPa, TS≥485 MPa, El≥22% |
| Flattening test | ASME SA-450 | One per heat / OD | No cracks until plates distance = 2/3 OD |
| Hardness | EN12952-2 C (optional) | Core and cladding | Core ≤179 HB, cladding ≤201 HB |
| Positive Material Identification (PMI) | XRF | Each tube (optional) | Confirm 304L chemistry |
Optional supplementary tests:
● Bond shear strength (destructive, on a sample)
● Intergranular corrosion (ASTM A262 Practice E on 304L cladding)
● Charpy impact (core, typical -20°C or 0°C)
● High temperature tensile (if requested)
Certificate: EN 10204 Type 3.1 (standard) includes chemistry of both layers, core tensile, hydro, UT and dimensional results. Type 3.2 with third-party witnessing available.
5. Applications in Detail
5.1 Boiler Water Walls (Subcritical and Supercritical)
In coal-fired power boilers, water wall tubes carry water/steam up to 450°C. Carbon steel alone can suffer from corrosion on the inner surface due to:
● Low pH during acid cleaning
● Dissolved oxygen
● Ammonia or other treatment chemicals
A 304L inner cladding protects against such attacks, extending tube life and reducing the need for chemical dosing. The SA 210 Gr.C core provides the necessary pressure strength.
5.2 Economizers
Economizers are subject to dissolved oxygen and low pH in the feedwater, causing pitting of carbon steel. 304L cladding eliminates this risk while maintaining high heat transfer efficiency. Many operators have switched to clad tubes after repeated corrosion failures.
5.3 Low-Temperature Superheaters / Reheaters
In the low-temperature sections of superheaters (below 450°C metal temperature), condensing contaminants (sulfur compounds) can create acid dew-point corrosion. 304L cladding prevents attack, allowing the use of lower alloy core material.
5.4 Shell & Tube Heat Exchangers
When the tube side fluid is corrosive (e.g., cooling water with low chloride, process water, or mildly acidic condensate), using SA-210+304L clad tubes saves cost compared to solid stainless steel. The tube sheets can be made of carbon steel with 304L weld overlay, achieving full corrosion protection at minimum expense.
5.5 Waste Heat Recovery Units (WHRS)
In units handling exhaust gases from gas turbines or industrial furnaces, the inner surface can be exposed to nitric acid, sulfuric acid, or other condensates. 304L cladding provides excellent resistance up to 400 450°C.
6. Advantages Over Alternatives
| Alternative | Comparison with SA-210+304L Clad |
| Solid SA-210 carbon steel | Lower upfront cost but fails quickly in corrosive service, leading to frequent replacement and downtime. |
| Solid 304L stainless steel | Fully corrosion resistant but 40-50% more expensive for same pressure rating; lower yield strength (170 MPa vs 245 MPa) means thicker wall needed. |
| Mechanically lined 304L pipe | Cheapest but liner collapses under thermal cycling or pressure pulsation; crevice corrosion at liner/base interface. Our metallurgical bond eliminates that risk. |
| 304L weld overlay on carbon steel | Can be effective but expensive, labor-intensive, and not uniform; cannot be applied to small diameter tubes. |
Key economic advantage: For a given design pressure of 10-15 MPa, the clad tube wall can be 60-70% of the solid stainless wall due to the higher yield strength of SA-210 Gr.C, reducing weight and material cost further.
7. Quality Assurance & Traceability
● Heat numbers: Both the SA-210 billet and the 304L plate/pipe have unique heat numbers, both are recorded and stamped on each finished tube.
● Material certificates: Supplier certificates for the raw materials (3.1) are kept in the quality dossier.
● Process logs: Extrusion temperature, heat treatment time-temperature chart, pickling bath analysis are recorded.
● Final release: Only after all specified tests pass and documentation is compiled.
We welcome customer or third-party inspections at any stage: raw material receiving, composite assembly, extrusion witness, NDT, or final dimensional check. Typical inspecting bodies: SGS, BV, DNV, TÜV, ABS, LR.
8. Packaging & Shipping
● Protection: Ends capped with plastic (or steel) caps; rust preventive oil on external surface (optional, specify if required). 304L inner surface is pickled and passive – no oil.
● Bundling: Small diameters (≤76 mm) are bundled with steel straps, wooden spacers between layers to avoid abrasion. Larger diameters (≥88.9 mm) are shipped individually in cradles or on flat racks.
● Labeling: Each tube marked: “SA 210 Gr.C / 304L – Heat #xxxx – OD x WT(core+clad) – Length – Womic”
● Container: Standard 20′ or 40′ containers for up to 12 m length. Longer tubes by open top or flat rack.
● Shipping term: FOB Shanghai/Tianjin (default), CIF/CFR to any major port.
Estimated lead time (first order): 14 16 weeks (including material sourcing and extrusion scheduling). Repeat orders 10 12 weeks. Small trial orders may be faster (10 12 weeks) if we can combine with a production run.
9. Frequently Asked Questions (FAQ) – SA 210+304L
Q1: What is the maximum service temperature for SA-210+304L clad pipe?
A: The limiting factor is the carbon steel core. SA 210 Gr.C is suitable for metal temperatures up to 450°C (842°F) per ASME Section I. Above that, creep life decreases rapidly. The 304L cladding can withstand higher temperatures, but the core sets the limit.
Q2: Can the 304L cladding be used with high chloride water?
A: 304L is susceptible to pitting and stress corrosion cracking in high chloride environments (>5000 ppm Cl⁻ at elevated temperatures). For high chloride service (e.g., seawater cooling), we recommend duplex (2205) or nickel alloy (Alloy 28 / 825) cladding. This product is best for low-moderate chlorides.
Q3: Is it possible to have SA-210+304L as U-bend tubes for heat exchangers?
A: Yes. We can cold-bend the pickled clad tube, then perform a full stress relief heat treatment (which also serves as post-bend annealing). After bending, 100% NDT of the bend area (UT or ET) plus dye penetrant. Please request a separate U-bend quote.
Q4: How do you prevent 304L cladding from being contaminated by carbon from the core during extrusion?
A: The vacuum assembly prevents oxygen from entering; at extrusion temperature, carbon does not migrate significantly across the interface because the bond forms by mechanical interlocking and limited interdiffusion. Post-extrusion analysis confirms that the cladding chemistry remains within 304L specifications (verified by PMI).
Q5: What’s the difference between SA-210 Gr.C and A106 Gr.B / P265GH?
A: SA-210 Gr.C has higher tensile strength (min 485 MPa) vs A106 Gr.B (415 MPa) and P265GH (410-570 MPa). SA-210 Gr.C is specifically intended for boiler tubes, while A106 is for general pressure piping. EN10216-2 P265GH is similar to SA-210 Gr.B (lower strength). For higher strength, we can also substitute SA-210 Gr.C with P265GH (which is more common in Europe). Please clarify which EN grade you need – we can also use P265GH as core instead of SA-210 Gr.C if your project requires EN standard.
Q6: Do you provide a weld overlay or buttering on the tube ends?
A: Standard delivery is plain square cut, deburred. If you require beveled ends with CRA buttering (a 304L weld deposit on the bevel face to prevent dilution during field welding), please specify. Additional cost and lead time may apply.
Q7: What inspection certificates do you provide for the 304L cladding?
A: We supply the original mill certificate of the 304L material (EN 10204 3.1) plus our own analysis of the finished clad tube (including PMI or OES from the cladding surface). For projects requiring 3.2 certification, we can arrange with a third-party inspector.
Q8: Can the clad tube be supplied with smaller OD (e.g., 19 mm) for instrumentation lines?
A: The extrusion route can produce OD down to 21 mm. For 19 mm or smaller, we may need to use cold drawing after extrusion. Please inquire.
Q9: Is the pickled surface on the carbon steel OD acceptable for painting?
A: Pickling leaves a clean, slightly rough surface, which is excellent for coating adhesion. If you require a specific surface profile (e.g., for epoxy coating), we can adjust the pickling parameters or provide a subsequent grit blast. However, standard pickled surface is ready for primer.
Q10: Is the cladding thickness guaranteed to be uniform?
A: Yes. Ultrasonic thickness mapping of the cladding (using a focused probe) shows that thickness variation is within ±0.2 mm for most sizes. We can provide a thickness map report.
Q11: What is the minimum order quantity (MOQ)?
A: For seamless clad pipe, the economic MOQ is approximately 500-1000 meters per combination. However, we accept trial orders of 100-200 meters for project qualification. Contact us to discuss small quantity possibilities.
Q12: Can you supply this clad pipe with ASME Section VIII, Div. 1 stamp?
A: We do not hold the ASME U-stamp ourselves, but we can supply the material to ASME specifications with full traceability and certificates. The end-user or fabricator must perform the code stamping. For critical applications, we can arrange third-party witnessing to satisfy ASME quality requirements.
10. Ordering Information & Contact
To request a quotation for SA 210 Gr.C / 304L seamless metallurgical clad pipe, please provide the following:
● Outer diameter (OD), core wall thickness, cladding thickness
● Length per piece (e.g., 6 m, 12 m) and total length (m)
● Applicable standard (ASME Section II, EN12952 2, or project spec)
● Any supplementary tests (bond shear, Charpy, intergranular corrosion)
● End finish (plain, beveled, beveled+buttering)
● Quantity (pieces or meters)
● Delivery term (FOB China port, CIF any major port, Air freight)
Womic Steel – Your partner for reliable SA 210 Gr.C / 304L clad pipe
Website: www.womicsteel.com
E-mail: sales@womicsteel.com
Tel / WhatsApp / WeChat:
Victor: +86 15575100681
Jack: +86 18390957568
Womic Steel – Tailored 316L clad pipe solutions for CO₂ service, boiler, heat exchanger, low temperature, and high temperature applications.
Related Products
-
SA-210 Gr.C / 304L Seamless Metallurgical Clad ...
-
High-Performance Bimetal Metallurgical Bonded S...
-
Bimetal Clad Pipe Manufacturer | Metallurgicall...
-
904L Stainless Steel Lined Clad Pipe | UNS N089...
-
316L Stainless Steel Lined Clad Pipe | Carbon &...
-
Slag Pot Material Selection Guide: ZG270-500, G...
-
Slag Pot Manufacturer | Heavy-Duty Cast Steel S...
-
LF/VD Slag Pot | Ladle Furnace Specialized Slag...
-
Large Slag Pot Manufacturer | Heavy-Duty 60-100...