316L Stainless Steel Lined Clad Pipe | Carbon & Alloy Steel Backing for CO₂ Service, Boiler, Heat Exchanger & Low Temperature – Womic Steel

Q1: What is the maximum temperature for 316L cladding in corrosive service?
A: 316L can be used up to about 450°C (840°F) in continuous corrosive service. Above that, sensitization (carbide precipitation) may occur, reducing pitting resistance. For higher temperatures, consider Alloy 825 or 625 cladding.

Q2: Can 316L clad pipe be used for sour service (H₂S)?
A: 316L is limited in sour service. NACE MR0175 / ISO 15156 allows 316L in sour environments only if: chloride content is low (<50 ppm), pH >3.5, temperature <60°C, and H₂S partial pressure <0.05 psi. For typical wet sour gas (high H₂S), we recommend Incoloy 825 or Alloy 28 cladding instead.

Q3: Which backing steel should I choose for a boiler water wall?
A: SA-210 Gr.C is the standard for water walls and economizers. If your boiler is subcritical and metal temperature <450°C, this is the most economical choice.

Q4: I need low temperature impact toughness (-45°C). Can I still use 316L cladding?
A: Yes. Choose backing steel ASTM A333 Gr.6 which is impact tested at -45°C. The 316L cladding does not affect impact properties; it remains ductile at low temperature. The overall clad pipe can be supplied with complete Charpy testing.

Q5: For high pressure CO₂ pipeline (1500 psi, 80°C), what combination do you recommend?
A: API 5L X65 backing (for strength) + 316L cladding 2.53.0 mm (for corrosion allowance). This is a standard sweet gas solution widely used in the Middle East and North America.

Q6: What is the difference between SA-106 Gr.B and SA-210 Gr.C for clad pipe?
A: SA-210 Gr.C has higher tensile strength (485 MPa vs 415 MPa) and is specifically intended for boiler tubing. SA-106 Gr.B is for general high temperature piping. For boiler applications, use SA210; for refinery transfer lines, SA106 is acceptable.

Q7: Can I get EN 10204 Type 3.2 certificates for these clad pipes?
A: Yes. We work with TÜV, BV, DNV, SGS, and ABS. A surcharge applies and lead time extends by 12 weeks.

Q8: Is the bond between 316L and carbon steel susceptible to hydrogen embrittlement?
A: In sweet CO₂ service (no cathodic protection overvoltage), no. In sour service (H₂S), the bond interface is not a preferential cracking path if properly made. However, the 316L itself has hardness limits. For high H₂S, we recommend nickel alloy clad.

Q9: What is the minimum 316L cladding thickness you recommend?
A: 1.5 mm is the minimum for reliable bond and corrosion allowance. For aggressive CO₂ service with high flow velocity, we recommend 2.53.0 mm.

Q10: Can you supply these clad pipes in Ubent configuration for heat exchangers?
A: Yes, for seamless clad pipe (OD ≤168 mm). We perform cold bending with mandrel, then stressrelief heat treatment and 100% NDT of bend area. Please request a separate Ubend quote.

Q11: Do you offer a “clad pipe selection tool” for different backing steels?
A: Yes. Send us your service conditions: max temperature, min temperature, pressure, fluid composition (CO₂, H₂S, chlorides, pH). We will recommend the optimal backing steel + cladding thickness + inspection level.

Q12: Is there a significant cost difference between SA-210+316L and solid 316L tube?
A: Yes. For a 63.5mm OD × 5mm wall tube, solid 316L is approximately 2.53 times more expensive than SA210+316L clad pipe (2mm cladding). The thicker the wall, the larger the saving.

Q13: Why would I choose seamless over welded clad pipe?
A: Seamless clad pipe eliminates any longitudinal weld seam, which is advantageous for high temperature cyclic service, hydrogen service, and where there is risk of chloride SCC attacking the weld. For most line pipe applications (X65+316L), welded clad pipe is very reliable and more economical.

Q14: Can you clad both the ID and OD?
A: We can, but that is a specialty. Typically a single CRA layer on the ID is sufficient. For external corrosion, we recommend paint, coating, or a separate external cladding process (e.g., weld overlay). Please inquire for dualclad.

Q15: How do I order a mixed combination of backing steels?
A: Provide line item for each: backing steel grade, OD, core WT, cladding thickness, length, quantity. We will quote per combination. Minimum trial order for one size is acceptable.

Q16: Is pickling necessary for 316L cladding?
A: Yes. Pickling removes heat scale formed during extrusion and heat treatment, restores the passive layer, and ensures clean surface for inspection. Our standard delivery is pickled and passivated. If you prefer no pickling (e.g., for immediate coating), please specify.

Q17: Do you provide PMI (Positive Material Identification) on the 316L cladding?
A: Yes. We can perform XRF at several points along each tube, and include the report in the quality dossier. There is a small charge per tube for large orders.

Q18: Can the clad pipe be supplied with beveled ends and CRA buttering?
A: Yes. Standard bevel angle 3035° with 1.6 mm landing. CRA buttering (23 mm of Alloy 625 or 316L filler on the bevel face) is available to prevent dilution during field welding. This is especially recommended for girth welds in high pressure service.

Q19: What is your experience with supplying 316L clad pipe to European EN standards?
A: We regularly supply to EN 102162 (backing) with 1.4404 (316L) cladding. We can provide EN 10204 3.2 certificates with TÜV witness and PED declaration. Many orders have gone to Germany, Netherlands, France, and UK.

Q20: Can you share references for large diameter 316L clad pipe (API 5L X65+316L)?
A: Yes, we have supplied X65+316L clad pipe (OD 610mm, cladding 2.5mm) for a Middle Eastern CO₂ injection project (200 km pipeline). References available upon NDA.