cladded pipe

[suraiya]

Hi,

when people talks about caldded pipe, what does that mean? does that mean you add some other materials to the original pipe material to strengthen it? how does the cladding process take place- physically or via certain chemical processes?

 

[reichertc]

Cladding is when you add a metal to the inside of a pipe for (typically) corrosion or erosion resistance. I am not aware of any circumstances where you are allowed to take credit for the mechanical strength of the cladding, although it can be used to reduce your corrosion allowance to zero in many cases.

There are a few techniques for cladding. Roll bonding "presses" two sheets of metal. Explosion bonding uses controlled explosions to bond the cladding to the base metal. Weld overlay adds a weld deposit to the surface of the material. (I am not sure if this is technically cladding, we always refer to it as overlay.)

In all cases, the intent is to use a cheaper parent material (like carbon steel) to provide the mechanical strength, and then use a relatively thin layer of alloy to provide corrosion or eerosion resistance.

Check out this website

http://www.corrosion-doctors.org/MetalCoatings/Cladding.htm

 

[MJCronin]

Hello,

Reichertc is correct in his description....

I would like to add that the piping codes, (ASME B31.1 and others) SPECIFICALLY do not allow any credit to be taken for the mechanical strength of the liner. The wall thickness calculation is the same with or without the liner.

Secondly, I would like to point out that metallic lined (or "clad&quotpipe only makes sense in "high pressure" and large diameter applications. (I do not believe that you can find it below 4 inch NPS) For many applications up to about 4 inch, piping made from the premium liner material is commonly used.

Also, because of the expense involved in the manufacturing and the stocking of such a material, you will not find it "on the shelf"

My thoughts, recollections only.......

MJC

 

[reichertc]

I just spoke with some gentlemen who do weld overlay two weeks ago, and they informed me that they are currently working on the technology to do overlays on pipe down to 1" diameter. I'll be pretty impressed if they can make it work. I know of a shop right now that can go down to 3" diameter piping. All dependant upon wall thickness of course.) I wouldn't mind trying to do some hardfacing of select piping sections on catalyst systems to determine how effective hardfacing would be at reducing erosion.