Metallurgically Bonded Corrosion Protection
DURACORE CRA clad pipe combines a high-strength carbon steel outer pipe (X60, X70) with a thin corrosion-resistant alloy inner liner. The RSP™ (Right Spinning Pressure) process creates a continuous metallurgical bond at the interface — bond shear strength ≥ 140 MPa per API 5LD.
Engineers specify clad pipe when solid CRA alloy is cost-prohibitive for long-distance pipelines, but carbon steel alone cannot withstand the corrosive media. Typical savings of 30–50% versus solid Inconel or duplex pipe, with equivalent corrosion resistance at the wetted surface.
Applications
- Oil & gas transmission and sour service (H₂S)
- Subsea and offshore platform piping
- Mining slurry and tailings conveyance
- Chemical and petrochemical processing
- CO₂ sequestration and CCUS pipelines
- Marine seawater cooling systems
Frequently Asked Questions
What is CRA clad pipe?
CRA clad pipe is a bi-metal composite pipe with a carbon steel outer wall for structural strength and a thin corrosion-resistant alloy (CRA) inner liner for media protection. The liner is metallurgically bonded to the outer pipe using ZONX RSP™ (Right Spinning Pressure) technology, achieving bond shear strength ≥ 140 MPa per API 5LD.
How long does clad pipe last?
Service life depends on operating conditions, but CRA clad pipe typically matches or exceeds the design life of the project — often 25–50 years in oil & gas and mining applications. The CRA liner provides the same corrosion resistance as solid alloy pipe while the carbon steel outer wall handles pressure loads.
What is the difference between clad pipe and lined pipe?
Metallurgically clad pipe (DURACORE) bonds the CRA liner to the outer pipe at the atomic level via spinning pressure, allowing cut, weld, and bend operations without delamination. Mechanically lined pipe (AQUACORE) inserts a liner by interference fit — lower cost but limited to lower-pressure applications like water service.
Which CRA grade should I specify for sour gas?
For sour service with H₂S, we recommend Inconel 825 (N08825) or Inconel 625 (N06625) liners per NACE MR0175/ISO 15156. For moderate corrosive environments, 316L or duplex 2205 may be sufficient. Our engineers can recommend the optimal grade based on your media composition and operating conditions.
Is ZONX clad pipe API 5LD certified?
ZONX PIPE holds API Monogram License 5LD-0017 (API Spec Q1 + API Spec 5LD, valid through August 2027, verifiable at api.org/compositelist). DURACORE clad pipe is manufactured under this quality management system in full accordance with API 5LD — bond shear ≥ 140 MPa verified by full-length ultrasonic testing. Every order includes Mill Test Reports and hydrostatic testing per GB/T 241-2007.