Penetration

By Wildturkey (**)

Date 08-06-2002 13:46

are you refering to partial joint penetretion or complete joint penetration? or what is the difference?

By Mike W

Date 08-07-2002 01:07

When would you know if you had partial penetration, thanks

By boilermaker (**)

Date 08-07-2002 02:36

Here's the rundown......
Partial penetration would be described as the unconsumption of the root face/faces for tube/pipe welding and for structural welds, the lack of filler metal protruding for the root face area. Full penetration would be filler metal being flush with the root faces or "pushing through" the root face. Or in a double-V groove weld with no root opening, the root pass would need to penetrate to the other side before the other side is welded....if there is no root reinforcement on the back side, backgouging or grinding is required to tie the back weld to the root pass weld
Hope this helps..

By Mike W

Date 08-07-2002 03:58

Thanks, one last question: Assume a 3/8" plate. You want to weld a 1/2" round rod vertical to the plate. Method one, the rod sits on the plate and you weld the two together. Method two, the rod has a taper on the end touching the plate. Again you weld the two together. Is method 2 superior?

By Tim Buyle (**)

Date 08-07-2002 06:21

It all depends on the type of loading on the construction ; for static loads a fillet weld can withstand a lot of forces, so you don't need to chamfer the rod. But for dynamic loads and bending one can prefer chamfering to obtain perfect penetration, resulting in a better flow of forces through the workpiece.
But the weld volume can cause distortion on your plate. So there's another method to obtain good penetration : drill a hole (diameter (1/2" + 3/16")) through the plate; chamfer the hole with a special bore. You can chamfer both sides (half X-groove) or only one side (half V-groove). If you prefer a V-groove, chamfer the bottom of the plate.
Set the rod through the plate and weld it together. The weld volume is now concentrated into the plate; resulting in less distortion (in the other case the volume is welded into the rod and on to your plate, resulting in stress and distortion)
Good luck.

By Mike W

Date 08-08-2002 02:56

Thanks Tim and everyone else.