Engineering explanation please (pipe welded to a wall)

[Hauzen]

Hello.
I work for a company and I need your help!

The pipe is welded to the wall.
However, the worker applied force to the right with the force of F, and the welding was cracked.

As a countermeasure, welding is carried out in two layers as shown in the picture on the right.
In this case, is it safer than before if the worker pulls the pipe with the force of F?
Can anyone explain to me about engineering? (Force, moment ....)

 

[Baluncore]

The drawing on the left is stronger as it has no sharp internal corners that will initiate cracks.
To make it stronger, there needs to be a diagonal brace, or the pipe diameter must be increased, but only after checking the thickness of the wall is sufficient.

 

[Lnewqban]

Is this related to your last thread?

Is the material (wall, welding electrode, pipe) low carbon steel?

It seems that the first weld could have been deffective (contamination, insufficient penetration, etc.) or not long enough around the perimeter of that pipe, unless the thickness of the wall of the pipe has greater dimmension than the cross-section of the weld fillet.

Two layers of deffective weld will not improve the situation much.

Please, see this link for a rough calculation of the strenght of weld fillets:
https://www.roymech.co.uk/Useful_Tables/Form/Weld_strength.html

Regarding the pulling force on that weld at the crak point:

Pulling force = (F x Lenght of pipe) / Exterior diameter of pipe

 

[Rive]

However, the worker applied force to the right with the force of F, and the welding was cracked.

As a countermeasure, welding is carried out in two layers as shown in the picture on the right.

My guess: welding thin materials is difficult. The welder might have been too careful with the pipe and made a cold weld, resulting in a crack when loaded.
For the second attempt, he may made a 'thickening run' first, so he could apply proper current/voltage for the second run resulting in a proper weld at the end.

Either way, you won't know without (proper) testing.

Ps.: if it's critical then just don't make this kind of direct pipe-on-wall thing. Add some brackets for proper load bearing.

 

[berkeman]

Ps.: if it's critical then just don't make this kind of direct pipe-on-wall thing. Add some brackets for proper load bearing.

Agreed. If you anticipate that kind of loading on the welded joint, you should add gusset strengthening pieces and welds:

 

[DeBangis21]

Agreed. If you anticipate that kind of loading on the welded joint, you should add gusset strengthening pieces and welds:

View attachment 346538

Gusset=bracket, learnt something now. Thanks!