Backing Rings
Backing Rings
(OP)
Can someone explain the use of backing rings? I'm trying to figure if I want to use them on my current job or not.
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RE: Backing Rings
RE: Backing Rings
RE: Backing Rings
if the done on vessel or large bore dia pipe, you may just perfrom a backweld, ground out, then do the other side for the hot pass followed by fill and cap.
It is not necessary on SS pipe provided you can argon purge during the root pass. It is not necessary at all for the cs pipe irrespective of wehter youre using tig or stick or the joint is slipon or sowcket.
RE: Backing Rings
Consumable Backing Ring Welding
Backing Rings are inserted into the beveled pipe end with the spacer nubs flush against the pipe land and the ring gap positioned in the area of first bead deposition. The beveled end of the adjoining pipe is slipped onto the backing ring until the edge of the pipe land is firmly abutted against the spacer nub. Depending upon the Ring Style chosen, the welder has the choice of "striking off" the nubs or leaving them intact.
The welder can either weld the split making a solid ring or weld away from the split allowing the heat of the molten metal to expand the ring forcing it tightly against the inner surface of the pipe. This eliminates gaps, openings, or crevices between the Backing Ring and the pipe, tube, valve or fitting. Flat outer surfaces afford immediate access to the root of the weld and allow complete penetration. The 1/16" lands on the outer ring edges prevent curling. The internal bevels and flat inner land minimize flow turbulence on the downstream side to a nearly incalculable degree.
During welding, the arc should be directed as to penetrate the backing ring and inner edges of the pipe or fitting. The molten metal should penetrate into the Backing Ring approximately forty to fifty percent of the cross-sectional dimension thereby forming an integral welded joint.
RE: Backing Rings
The negatives (besides added cost) are that backing rings can and have broken free after the piping goes into service causing havoc in the system. It can also boost a welders confidence to high and negatively affect the interpretation of various forms of NDE.
The decision is yours but I find them to be more trouble than they are worth for the more basic materials.
Lane Baker
Baker Quality Services
LaneBQS@att.net