New solution mechanical bonding CRA lined pipes

CRA lined pipes or CRA clad pipes are corrosion resistant pipes consisting of a corrosion resistant inner pipe and a carbon steel outer pipe that can withstand internal and external pressure. Potential applications for pipes with CRA material are: subsea pipelines for sour gas and oil, water reinjection systems, saltwater pipelines, process pipes in the chemical industry etc.

CRA lined pipes are mainly used as:

• Flow-lines
• Riser pipelines
• Interfield pipelines
• Water injection pipelines

There are two methods of bonding the CRA material to carbon steel:

• Metallurgical bond (CRA clad pipes)
The metallurgical bond between 2 different metals (bonding of plates) is achieved by hot rolling, co- extrusion, weld overlay or explosive bonding. Disadvantage is the limited number of suppliers due to the demanding and complex manufacturing process of metallurgical bonding the plates, which creates high costs.
• Mechanical bond (CRA lined pipes)
Mechanical bonding between the backing steel pipe and the CRA pipe by use of spring back variation, this can be done by means of Hydroforming or our Full Length Pipe Expander

Market Growth

There is growing demand for CRA lined pipe, due to the fact that corrosive conditions will increase significantly in the future as the produced fluids will contain higher water cuts and greater concentrations of H2S and CO2. In addition, these increasingly corrosive products need to be transported over longer distance, with higher pressures, and in an environmental friendly way.
Full Length Pipe Expander for Bonding CRA Lined Pipes

Fontijne Grotnes is proud to announce that we have found a solution to bond the backing steel pipe and the CRA pipe with our Full Length Pipe Expander, for which a Patent is Pending.

Fontijne Grotnes has more than 40 years experience (know how) in designing and manufacturing Full Length Pipe Expanders for the LSAW pipe industry. The expander head, actuated by the main cylinder and horn and drawbar expands the pipe sections from the inside. This will guarantee a constant production process according to API 5L through:

• Calibration of the pipe over the full length in roundness and diameter
• Straightening of the pipe
• Testing of the pipe weld seam
• Stress relief of material in way of the weld zone
• Improvement of mechanical properties by exceeding the material yield strength


For bonding CRA lined pipes by means of a Full Length Pipe Expander the inner and outer pipe are telescopic aligned and subsequently positioned on the infeed and outfeed loading cart. The pipe is fed incremental with use of the loading cart over the expander head.

A special expander head design is used to ensures uniform mechanical bonding of the inner and outer pipe over the complete contact area. The Full Length Pipe Expander is equipped with a linear transducer which accurately measures the position of the dies, such that the optimum in mechanical bonding for each inner and outer pipe material combination can be achieved.

Why Invest in a Full Length Pipe Expander?

Some manufacturers use Hydroforming machines for bonding purposes. Compared to the Full Length Pipe Expander the Hydroforming machine is an expensive investment. Another disadvantage of this process is the expensive tooling and material waste at pipe ends due to the seals of the Hydroforming machine.

The Fontijne Grotnes Full Length Pipe Expander is a more controlled and economical solution for the market. This creates an optimum mechanical bonding for each inner and outer pipe combination, as our process has diameter position control and does not require expensive outer dies.



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