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Womic Steel Bimetal Metallurgical Clad Pipe | CRA Lined Pipe for Oil & Gas, Hydrogen & Deepwater Service Featured Image
  • Womic Steel Bimetal Metallurgical Clad Pipe | CRA Lined Pipe for Oil & Gas, Hydrogen & Deepwater Service
  • Womic Steel Bimetal Metallurgical Clad Pipe | CRA Lined Pipe for Oil & Gas, Hydrogen & Deepwater Service
  • Womic Steel Bimetal Metallurgical Clad Pipe | CRA Lined Pipe for Oil & Gas, Hydrogen & Deepwater Service

Womic Steel Bimetal Metallurgical Clad Pipe | CRA Lined Pipe for Oil & Gas, Hydrogen & Deepwater Service

Short Description:

Size Range: OD 60mm – 1800mm (2″ – 72″), cladding thickness 0.5 – 3.5mm (as required), backing steel wall thickness per API 5L or customer specification, single random length up to 15m, custom lengths available.

Backing Steel Material: API 5L X52, X60, X65, X70, X80; X65MS (sour service); ASTM A106 Gr.B, A333 Gr.6, A335 P5/P11/P22; carbon steel and low alloy steel grades.

CRA Cladding Material: Austenitic stainless steel 304/304L, 316/316L, 904L; Duplex / Super Duplex 2205, 2507; Nickel based alloy Inconel 625, Incoloy 825, Hastelloy C-276; Martensitic stainless steel Super 13Cr; Selection based on H₂S/CO₂/Cl⁻ service conditions.

Manufacturing Process: Metallurgical bonding by hot roll bonding / extrusion bonding / explosive cladding; interface shear strength >300MPa; meets API SPEC 5LD and GB/T 37701. Backing steel provides mechanical strength; CRA cladding provides corrosion resistance.

Standards & Certifications: API SPEC 5LD, SY/T 6623, GB/T 37701, DEP 31.40.20.32 (Shell), NACE MR0175 / ISO 15156, DNV, ABS, Lloyd’s Register, EN 10204 Type 3.1/3.2.

Applications: Deepwater oil & gas transmission, sour gas field gathering lines, hydrogen transmission pipelines, CCUS-EOR CO₂ injection lines, refinery piping, chemical plants, power generation (including boiler tubes and coal ash slurry lines), mine tailings slurry transport. Widely used in offshore projects, hydrogen pilot pipelines, and carbon capture demonstration projects. Third party inspection (SGS, BV, DNV, TÜV, ABS, LR) available upon request.

Womic Steel supplies high quality bimetal metallurgically bonded clad pipes – combining the mechanical strength of carbon steel with the corrosion resistance of CRA. Offers 30-50% cost saving compared to solid CRA pipe. Suitable for extreme sour service, deepwater, and hydrogen applications. ISO 9001, PED, API 5LD ready. Contact us for engineering support and project-specific clad pipe solutions.


Product Specifications

Product Detail

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1. Product Overview – What is a Bimetal Metallurgical Clad Pipe?

Bimetal metallurgical clad pipe (also known as CRA clad pipe, corrosion resistant alloy metallurgically bonded pipe) is a high-performance composite tube produced by advanced metallurgical bonding processes that permanently join a corrosion resistant alloy (CRA) inner layer to a highstrength carbon steel or low alloy steel outer layer at the atomic level. The typical structure is “CRA inner cladding + high-strength steel outer backing”.

This “internal corrosion resistance + external mechanical strength” design solves a critical engineering challenge: how to reliably transport aggressive fluids (high H₂S, high CO₂, high chlorides) under high pressure and deepwater conditions without using expensive solid alloy pipes.

The technology was pioneered in China in 2004 through collaboration between Xinxing Ductile Iron Pipe, Panzhihua Steel and University of Science and Technology Beijing, with subsequent breakthroughs by CNPC BSS, Ansteel Group, and Baoshi Pipe Industry. These developments enabled industrial scale production of metallurgically bonded clad pipes for deepwater oil & gas, sour gas fields, hydrogen transmission, and CCUS projects.

Womic Steel, building upon this internationally recognized clad pipe technology, integrates vacuum hot roll bonding, centrifugal casting + hot extrusion, and advanced welding techniques that manage the dissimilar metal fusion between nickel alloys and pipeline steel. We supply clad pipes from 60mm to 1800mm OD with flexible wall thickness configurations, strictly meeting the most demanding international standards.

Product Architecture – Backing Steel & CRA Cladding

Component Material Examples Function
Backing Steel (Outer layer) API 5L X52/X60/X65/X70/X80; X65MS sour service; A106 Gr.B; A333 Gr.6; A335 P5/P11/P22 Provides mechanical strength, pressure containment, toughness, weldability
CRA Cladding (Inner layer) 316L, 904L, 2205, 2507, Inconel 625, Incoloy 825, Hastelloy C276, Super 13Cr Provides corrosion resistance against H₂S, CO₂, chlorides, organic acids

Typical dimension example for deepwater application: OD 610mm (24”), backing steel wall thickness 16.9mm (X65MS sour service grade), CRA cladding thickness 2.0mm (Inconel 625). Maximum wall thickness can reach 38mm, pressure rating up to 38.8 MPa, service temperature up to 120°C.

2. Why Choose Womic Steel Bimetal Metallurgical Clad Pipe?

Feature Technical Advantage Business Benefit
True Metallurgical Bond Interface shear strength >300MPa (exceeds API SPEC 5LD). No risk of liner collapse, blistering or delamination. Eliminates catastrophic failure risk; suits cyclic temperature and high-pressure service
CRA + Carbon Steel Integration Only the inner surface uses expensive alloy; backing steel provides loadbearing capacity. 30-50% cost reduction compared to solid CRA pipe
Tailored for Extreme Service Full range of CRA materials matched to H₂S, CO₂, Cl⁻, pH, temperature and pressure. Reliable performance in sour gas, deepwater, and hydrogen service
Proven Manufacturing Routes Vacuum hot roll bonding / centrifugal casting + hot extrusion / explosive cladding + cold finishing. Consistent quality, large diameter capability, scalable production
Weld End Preparation Factory CRA strip cladding (buttering) on pipe bevels; machined transition. Simplified field welding, retains corrosion resistance in girth welds
Full Traceability & Global Certification EN 10204 3.1/3.2 certificates. Third party inspection (DNV, BV, SGS, TÜV, ABS, LR) available. Accepted by major EPCs, NOCs, and offshore operators

3. Technical Specifications & Material Selection Guide

3.1 CRA Cladding Material Selection by Environment

Service Environment Recommended CRA Cladding Application Examples
CO₂ dominant, low chlorides 316L stainless steel Onshore gas pipelines, sweet service
CO₂ + moderate chlorides 2205 / 2507 duplex stainless steel Seawater injection, topside piping
H₂S + CO₂ + Cl⁻ (sour service) Inconel 625, Incoloy 825, Alloy 028 High-sulfur gas fields, acidic oil wells
Deepwater, high H₂S, high pressure Inconel 625 / Alloy 825 clad Subsea flowlines, risers, deepwater projects
Hydrogen transmission / CCUS 316L, duplex, or nickel alloys Hydrogen pipelines, CO₂ injection lines

3.2 Backing Steel Options

Base Material Standard Typical Grade Suitable Conditions
API 5L PSL1/PSL2 X52, X60, X65, X70, X80 High pressure oil & gas transmission
API 5L sour service X65MS, X52NS Wet H₂S service (sour gas)
ASTM A106 Gr.B, Gr.C High temperature, refinery service
ASTM A333 Gr.6 Low temperature (-45°C)
ASTM A335 P11, P22 High temperature steam, petrochemical
DNV offshore grades DNV450, DNV500 Subsea pipelines, deepwater risers

3.3 Applicable Standards & Certification

● Primary standards: API SPEC 5LD (worldwide), SY/T 6623 (China), GB/T 37701, Shell DEP 31.40.20.32

● Material & corrosion compliance: NACE MR0175 / ISO 15156 for H₂S service

● Offshore / classification: DNV, ABS, LR, CCS (China Classification Society)

● Quality documentation: EN 10204 Type 3.1 (standard) or 3.2 (third-party verified)

4. Manufacturing Process – Metallurgically Bonded Clad Pipe

Womic Steel leverages worldclass clad pipe manufacturing routes to ensure consistent metallurgical bonding and dimensional precision.

Process Flow (Hot Roll Bonding + Cold Finishing):

1.Composite slab preparation – Clean and vacuum seal CRA plate + backing steel plate to remove oxygen; hot rolling at high reduction ratio creates metallurgical bonding with interdiffusion layer.

2.Hot rolling / extrusion to pipe form – The composite slab is either rolled into a plate then formed and welded (LSAW clad pipe) or extruded into seamless clad pipe using centrifugal casting + extrusion process.

3.Cold drawing / cold rolling – Further reduces diameter and wall thickness, improves surface finish and dimensional accuracy while maintaining bond integrity.

4.Heat treatment – Normalizing, normalizing + tempering, or quenching + tempering (Q&T) to achieve required mechanical properties and stress relief.

5.NDT inspection – 100% ultrasonic testing for bond integrity and laminar defects; eddy current and radiographic testing as required.

6.End finishing & CRA buttering – Weld end bevels are prepared; corrosion resistant alloy strip cladding is applied to the bevel face to prevent dilution of CRA during field welding.

7.Final inspection & documentation – Complete dimensional check, visual inspection, hardness measurement, and packaging per export standards

5. Key Advantages – Technical & Economic

● Solve pipeline corrosion bottleneck – Dramatically improves reliability in H₂S, CO₂, Cl⁻, and acidic environments; prevents corrosion leaks and premature failure.

● Lower life cycle cost – Up to 30-50% material cost saving compared to solid nickel alloy or high-alloy pipe.

● Reduced carbon footprint & alloy consumption – Ideal for hydrogen economy and CCS projects where sustainable material use is valued.

● Wide size range & stable supply – OD from 60mm to 1800mm; wall thickness and length can be customized for long trunklines and deepwater reel-lay installation.

● Project-specific certification support – Provide API 5LD, DNV, ABS product approvals, welding procedure qualification records (WPQR), and manufacturing inspection plans as required by clients.

6. Primary Applications – Where Clad Pipe Excels

● Deepwater oil & gas export pipelines – Subsea flowlines, risers, and trunklines handling corrosive, high-pressure reservoir fluids.

● Sour gas onshore gathering systems – High H₂S/CO₂ fields (e.g., Sichuan basin, Middle East) requiring reliable CRA protection.

● Hydrogen transmission & CCUS – Bimetal clad pipe has been selected for pilot hydrogen pipelines and CO₂-EOR projects (including CNPC and Daqing CCUS) due to hydrogen embrittlement resistance and cost effectiveness.

● Refinery & petrochemical plants – High temperature sulfur recovery units, hydrotreating, and chlorinated process streams.

● Power generation & mining – Coal ash slurry pipelines, FGD scrubber lines, and high-abrasion tailings transport.

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7. Packaging & Logistics – Global Delivery

7.1 Surface Protection & End Capping

● Exterior coating: black or light-grey epoxy primer (film thickness and colour per customer specification).

● Pipe bevels: rust preventive oil + plastic/metal end caps or steel rings to prevent damage and contamination.

7.2 Bundling, Stowage & Moisture Control

● Small diameters: bundled with steel straps and separated by wooden spacers to avoid metaltometal abrasion.

● Large diameters: individually stowed in containers or on flat racks with padded supports.

● Moisture protection: waterproof tarpaulin + desiccant for longsea freight.

7.3 Shipping Documentation Package

● EN 10204 Type 3.1/3.2 mill certificates (chemistry, tensile, impact, hardness, bond shear strength)

● NDT reports (UT, MT, PT)

● Dimensional & final inspection report

● Packing list with photos (inside container/vessel)

● Welding procedure & qualification records (if required)

● Heat treatment charts & batch traceability

7.4 Transport Modes

● Containerized (20'/40') for OD up to ~800mm

● Flat rack / open top for larger diameters

● Break bulk or project cargo for heavy wall / long length clad pipes

8. Project References & Certifications

8.1 Representative Projects

● CNOOC “Deep Sea No.1” – First application of “deepwater large-diameter seamless steel pipe + deepwater bimetal clad pipe” hybrid solution (approx. 114 km of clad pipeline).

● Baoshi Pipe Industry / CNPC BSS (Qinhuangdao) – Successfully produced N06625 / X65MS clad pipe (OD 610mm) with full classification society approval (CCS).

● Ansteel Group – Supplied DNV450 sour service clad pipe with Inconel 625 inner layer for Abu Dhabi offshore gas project (Hail & Ghasha).

● China Aerospace Science & Technology – Won bid for CNPC hydrogen transmission pilot line and Daqing CCUS-EOR injection pipeline using bimetal clad pipe.

8.2 Certifications Held / Available

● API 5LD product license (available upon request)

● ISO 9001:2015, PED 2014/68/EU

● NACE MR0175 / ISO 15156 conformity

● Third-party witness classification: DNV, ABS, LR, BV, CCS, SGS, TÜV

9. Frequently Asked Questions (FAQ)

Q1: What is the essential difference between metallurgical clad pipe and mechanically lined pipe?

A: Mechanically lined pipe relies on interference fit to hold the liner – under thermal cycling and pressure pulsations, the liner can wrinkle, collapse or separate. Metallurgically bonded clad pipe forms an interdiffusion layer at the interface (shear strength >300 MPa). There is no risk of liner delamination, making it mandatory for deepwater, hydrogen and high-temperature cyclic service.

Q2: Can Womic Steel recommend specific CRA cladding for my corrosive service?
A: Yes. Our engineering team evaluates your fluid composition (H₂S, CO₂, Cl⁻, pH, organic acids), operating temperature and pressure – then recommends the most costeffective CRA from 316L → duplex → nickel alloys. For hydrogen projects we add additional hydrogen embrittlement screening.

Q3: What is the typical delivery time for API 5LD certified clad pipe?
A: For first-article certification and batch trial production about 6-8 months (including type approval and witness testing). For standard repeat orders: 60120 days depending on OD, CRA material and third-party inspection requirements.

Q4: How does Womic Steel ensure girth weld corrosion resistance at field joints?
A: We apply factory CRA strip cladding (buttering) on both pipe bevels plus a machined transition. This prevents dilution of the CRA by the backing steel during field welding. The welding procedure for girth joints is qualified with Alloy 625 / 825 filler metal to maintain corrosion performance equivalent to the pipe body.

Q5: How much cost saving can bimetal clad pipe provide compared to solid CRA pipe?
A: Based on case studies, a properly designed metallurgically bonded clad pipe saves 30-50% of total material cost compared to solid nickel alloy or high-alloy pipe of the same pressure rating. Savings increase as diameter and wall thickness increase.

Q6: Is clad pipe suitable for sour service (H₂S) and approved to NACE?
A: Yes. The CRA cladding (e.g. 625, 825, 2205, 316L) combined with a suitable backing steel (e.g. X65MS, X52NS) can be supplied fully compliant with NACE MR0175 / ISO 15156 and API 5L Annex H. Hardness, SSC and HIC testing can be performed and documented.

10. Request a Quote

Womic Steel offers tailor-made bimetal metallurgical clad pipe solutions – leveraging the strength of carbon steel and the corrosion resistance of CRA. We serve deepwater oil & gas, onshore sour fields, hydrogen pipelines and CCUSEOR applications worldwide.

Website: www.womicsteel.com
E-mail: sales@womicsteel.com
Tel / WhatsApp / WeChat:

Victor: +86 15575100681

Jack: +86 18390957568

Womic Steel – Your reliable partner for metallurgically bonded clad pipe technology, supporting critical energy transition projects with durable, cost-effective composite piping.

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