All you need to know about CRA Clad Pipe
You may have heard of something called “Clad Pipe” or “CRA Pipe” but wondered what it is, what the nuances of it are, and how the supply market is structured and who the manufacturers are?
So, what is clad pipe? The clad pipe is standard carbon steel or low alloy pipe (often called base metal or backing steel) that has cladding material (corrosion resistance alloy (CRA) such as Inconel 625, 825 or other) bonded to that base metal, most often internally. This bonding can be achieved using a variety of methods, such as hot rolling, coextrusion, explosion bonding, weld overlay, or powder metallurgy. More generally the technological processes of bonding can be grouped into two main categories: 1) metallurgically bonded, and 2) mechanically bonded.
In the metallurgically bonded process, the cladding is bonded with a base metal pipe through a rolling/pressing process (Hot Roll Bonding (HRB)). There are other methods to achieve this, however, the HRB process is the most common. Metallurgically bonded clad pipe is the preferred choice for pipelines and high-risk applications due to its high quality and reliability, however, the HRB process for producing pipe is costly and complex with a limited number of capable suppliers.
With mechanically bonded clad pipe the cladding is mechanically attached to the base metal pipe using two different methods: 1) cladding, in the form of a pipe, is telescopically inserted into the base metal pipe and then mechanically or hydrostatically expanded, or 2) using the weld overlay method, cladding is welded to the surface of the base metal pipe. Mechanically bonded clad pipes are significantly lower in costs (up to 50%), and much faster to produce (sometimes up to 40% faster) however are limited in the maximum diameter that can be produced and present more integrity concerns arising out of the cutting of ready pipes.
The main suppliers and manufacturers of CRA line pipe are detailed below.
It shall be noted that:
- Butting, JSW, EEW and EBK are the global leaders in the metallurgically bonded segment
- Proclad and Cladtek are global leaders in the weld overlay business
- Butting also dominates the mechanically bonded segment
- CRA Inconel plates are produced by 3 manufacturers only (JSW, Voestalpine and Industeel/ArcelorMittal)
Lead times are between 7-12 months, largely depending on availability of CRA material (up to 3-4 months) and manufacturing plant utilization. Production of CRA line pipe is very slow, so an order of 50km of large diameter pipe may fully utilize a plant for a full 12 months period.