Steel bar to plate - Weld capacity
Steel bar to plate - Weld capacity
(OP)
Hi,
I would like to know what tensile force the following welded connection can carry. A 16mm bar (500MPa yield strength) welded to a 20mm thick plate (350MPa).
The connection was welded as follows:
A 20mm diameter hole drilled in plate, bar pushed through and plug welded on bottom. The gap between bar and plate then filled with in weld pool, the protruding bar was then welded with 6-7mm fillet weld all round. See attached pics
I would like to know what tensile force the following welded connection can carry. A 16mm bar (500MPa yield strength) welded to a 20mm thick plate (350MPa).
The connection was welded as follows:
A 20mm diameter hole drilled in plate, bar pushed through and plug welded on bottom. The gap between bar and plate then filled with in weld pool, the protruding bar was then welded with 6-7mm fillet weld all round. See attached pics





RE: Steel bar to plate - Weld capacity
RE: Steel bar to plate - Weld capacity
RE: Steel bar to plate - Weld capacity
RE: Steel bar to plate - Weld capacity
RE: Steel bar to plate - Weld capacity
Regards
RE: Steel bar to plate - Weld capacity
Normally a 6mm fillet weld would give about 0.5kN/mm capacity, so that would give 25kN capacity for a 6mm weld around the 16mm bar.
RE: Steel bar to plate - Weld capacity
carbon contents less than 0.35%, and no more then .55%.
RE: Steel bar to plate - Weld capacity
RE: Steel bar to plate - Weld capacity
How can you determine what capacity is without more info?
Welds look suspect, how can you deteremine capaticy with out knowing procedures and critical elements of the weld?
RE: Steel bar to plate - Weld capacity
RE: Steel bar to plate - Weld capacity
The plate - although it "looks" clean (is not rusted like the rebar!) was NOT ground clean either before welding. Weld "quality of workmanship" stinks - spatter, shape, penetration, grinding, etc.
I don't trust the joint.
RE: Steel bar to plate - Weld capacity
If this weld was made by GMAW short arc transfer (noting the excessive spatter), it most likely has lack of fusion and lack of penetraion at the root. I would not trust it. Also the hardness of the rebar (Grade 60?) HAZ is expected to be > 300 BHN.
RE: Steel bar to plate - Weld capacity
These joints are beyond untrustworthy, they are almost guaranteed to fail at less than half the design strength. If the welds were GMAW/MAG on dirty rebar, you might even be able to get that 'weld' to break loose with a couple of well-placed whacks with a hammer.
RE: Steel bar to plate - Weld capacity
RE: Steel bar to plate - Weld capacity
That one is even worse, even more dangerous.
A proper full-penetration weld underneath would need a weld prep angle the size of 1/2 diameter of the rod all the way around the hole.
The weld prep area AND the rebar rod need to be clean and ground clear of all previous rust and debris.
The weld then joins the prep area and the rod.
But none of that happened. Worse, there isn't even any "blob" of weld metal outside of the plate to act as even a brake or offer resistance to pulling.
In the first photo, the rod is cut flush to the plate -> Therefore a "fillet" weld cannot exist. The end of the rod is melted sort of into the plate, but there is no room to develop any strength between the rebar rod and the plate. The weld itself - regardless of shape or prep angle - is a failure (heat, shape, porosity, fusion, etc.
RE: Steel bar to plate - Weld capacity
Re the 20mm plate for which I received the drawing the following day after we had completed the job. I used my own expertise and experience and punched 18mm holes in the four corners and plug welded it with a 10mm fillet weld on the other side
Step 1 – grind mill scale around the area to be welded. Grind mill scale on Y16 bar, set amperage at 280 and weld all the way around the Y16 bar. Please refer to the rough sketch sent
RE: Steel bar to plate - Weld capacity