American Welding Society Forum
QN 1: What is the difference between weld metal overlay and cladding? Any articles to read?
QN 2: In one the coolers we are fabricating has weld metal overlay (90/10 Cu-Ni) for inlet flanges and Monel 60 for Tube side & cover flanges ? what is the diff. between these two overlays? any cost related/advantages?
QN 3: If we use normal CS electrodes near (in the HAZ of weld overlayed by Cu-Ni/Monel) overlayed areas it will affect the metallurgy of overlay? it has to be addressed in welding procedures?
If it is for strength and or thermal purposes, then it would be cladding. For instance, Pen stock claddings for mechanical protection against erosion and impacts.
If it is for corrosion protection, or for example the stainless overlay of a reactor head to protect from boric acid concerns, or other similiar use, then it would be an overlay.
Difference is in service
Possibly, be sure it's approved by welding engineering and welded to a valid PQR/WPS
I am going to expand the discussion by CWI555 for QN 1
One main difference, cladding can be applied via mechanical (rolling or explosive) or by fusion welding methods. Typically, it provides a barrier coating to corrosive environments and is designed to protect the substrate.
The main difference between cladding and weld overlay is that weld overlay (by codes and standard definition) is deposited by a fusion welding process, and not applied by mechanical methods. Weld overlay can be used to restore structural integrity, corrosion protection, hardfacing to deter wear and abrasion.
Which type of equipment and which kinds of service is cladding typically found? Does a U-1 address cladding?
Nevermind. I am going back to the off topic bar and grill where I belong. :)
90/10 Cu-Ni is an alloy known as Cupronickel. Monel 60 is 60% nickel and 40% copper. Both are used for corrosion and heat resistance, monel being better than cupronickel. Due to its higher nickel content, it's also much more expensive, so it's used when cupronickel isn't suitable.
Information: Monel is a trade mark of Inco (the former International Nickel Co.) You can visit their site and learn more about nickel alloys.
Giovanni S. Crisi
Sao Paulo - Brazil
I thank everybody for their valuable inputs? is there any article to read about the overlay types (CRO/HFO/Cladding) and how they are applied on the materials, process etc? for information?
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