Maximum thickness of fillet weld
Maximum thickness of fillet weld
(OP)
A 1" thick cover plate is being welded to a HSS 8x8x1/4 (steel tube section). One reference stated that the governing material will be the thicker of the two (in this case 1" cover plate). The reference states that if the coverplate is greater that 3/4" then a 5/16" minimum fillet weld should be used. But does the 1/4" tube thickness not limit the maximum weld size to 1/4"?
Thanks
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RE: Maximum thickness of fillet weld
Dik
RE: Maximum thickness of fillet weld
the HSS 8x8x1/4 is a truss member that is 9 ft long. The 1" thick x 7" wide x 9 ft long cover plate is being used to strengthen the HSS member (i.e. add more cross sectional area to the HSS member). The reference is "Bridge Engineering, Design, Rehabilitation, and Maintenance of Modern Highway Bridges" by Tonias and Zhao.
RE: Maximum thickness of fillet weld
Normally a fillet weld cannot be larger than the smallest material thickness.
desertfox
RE: Maximum thickness of fillet weld
RE: Maximum thickness of fillet weld
note a...for non-low-hydrogen processes w/o preheat calculated....T equals thickness of the thicker part joined; single pass welds shall be used. For non-low-hydrogen process using procedures established to prevent cracking.....and for low-hydrogen processes, T equals thickness of thinner part joined; single pass requirement does not apply.
note b....except that the weld size need not exceed the thickness of the thinner part joined.
note c....min size for cyclically loaded structures shall be 3/16.
So you are looking at 5/16 or 3/16 depending on your electrode and process. Hope that helps.
ZCP
www.phoenix-engineer.com
RE: Maximum thickness of fillet weld
ZCP
www.phoenix-engineer.com
RE: Maximum thickness of fillet weld
I presume that the stated code is similar to AISC 9th ed. in that basing the weld size on the larger plate is due to proper heating. However enough heat to create a 5/16" weld may burn through a 1/4", so limit yourself to a 1/4". A good welder can do it.
I would agree with ZCP, though. I'd make the plate 8" wide and just do a flare bevel weld.
RE: Maximum thickness of fillet weld
Without doing any calcs, that looks like a lot of area to develop at both ends of the 9' long plate.
Timing has a lot to do with the outcome of a rain dance.
RE: Maximum thickness of fillet weld
ht
Hg
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RE: Maximum thickness of fillet weld
Preheat would be based on the thicker member, but if you use a low hydrogen process the preheat for the 1/4 wall HSS and the cover plate would be the same.
The bridge code doesn't address tubular members, so D1.1 would most likely be the default welding standard. That being the case, the fillet welds would not have to be single pass if the low hydrogen welding process was used.
The fillet weld size is going to be limited by the (wall) thickness of the thinner member (HSS) so the weld doesn't fail by punch shear. I believe the allowable stress is .4 YS not to exceed .6 TS of either member. In other words a very large weld on a thin member is simply going to fail by pulling out a chunck of the thinner member with the attached weld when subjected to a high load.
Best regards - Al