Re: Comparing buttweld and socketweld joints

From: <jcluf>
Date: Mon Jul 25 2005 - 20:10:00 EDT

Socket Welds are specifically forbidden in B31.3 Chapter 9 "High Pressure Piping" This is because in High pressures the fittings dilate due to internal pressure, this dilation puts shear stress across the toe of the fillet and can lead to premature pressure based fatiuge cracks....

Socket welds may also be prohibited in other codes under some cirmcumsatnace as well... check the applicable code thoroughly...

Whats stronger? The butt weld joint has a SIF of 1.0 the SW may be as high as 2.1 under some codes. From a thermal and pressure fatiuge standpoint the butt weld is significantly stronger.

A compromise between an as welded SW and a butt weld is the unequal lwg 2:1 tapered fillet as shown in B31.1 and B31.3 its significantly "stronger" than a standard fillet but not as strong as a butt weld.

Of course all welds are only as good as the welder making them! Received on Mon Jul 25 20:10:00 2005

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