welding tubes with a fillet weld

[wwwfarmer]

Hello everyone! I am designing a tractor implement for harvesting root crops. Similar to this one (

), but stronger construction with cutting discs in front of it to prevent weed jam. These images will help you understand my question. The whole implement is 1400mm wide and the pipe at angle is 200mm long relative to x axis

weld1

Image weld1 in Krompir's images album

ibb.co

weld2-txtv2

Image weld2-txtv2 in Krompir's images album

ibb.co

weld3

Image weld3 in Krompir's images album

ibb.co

The main frame has 2 square pipes welded together at 45 degree angle at each side. The pipes are 120x120mm(4 3/4"x4 3/4") with wall thickness 8mm(0.315"). I was sceptical about using butt joint so I put a 15mm(5/8") steel plate between pipes. Now the pipes are welded with a fillet weld with the steel plate (at 90°, 45° and 135°). I'd like to hear some expert or practitioner opinion on how structurally stable welding pipes in such arrangement is with respect to flat pipe without any welds. The forces will act on the sides, that are just 20cm(8") from the three point hitch arms so the leverage is pretty small.

Thanks!

 

[ArlyA]

Interesting project and I'd like to see how it turns out. Some terminology might be helpful. Pipes are round tubes usually for liquids under pressure. Square tubes are structural and as there name implies, square or rectangular shaped. Yes I know, the English language is a mess.

So I'd guess you don't have a wire welder? Those would be very large fillet welds to do and would be challenging.....

 

[LD1]

If I were building it, is cut a 45 degree triangle out of the square tube and bend it to 45 degrees and reweld.

The slip your 5/8" plates over the tube and weld them.

I think you are overthinking it.

The video of the commercial ones are straight. Why the 45 degree bend? Do you need that room to clear the discs?

 

[wwwfarmer]

Thank you both for stopping by. I had not idea english has a special word for square pipe thanks for letting me know. LD1, you guessed it. The cutting disks are simply to large to be mounted a machine with a single tube.

 

[etpm]

Hello everyone! I am designing a tractor implement for harvesting root crops. Similar to this one (

), but stronger construction with cutting discs in front of it to prevent weed jam. These images will help you understand my question. The whole implement is 1400mm wide and the pipe at angle is 200mm long relative to x axis

weld1

Image weld1 in Krompir's images album

ibb.co

weld2-txtv2

Image weld2-txtv2 in Krompir's images album

ibb.co

weld3

Image weld3 in Krompir's images album

ibb.co

The main frame has 2 square pipes welded together at 45 degree angle at each side. The pipes are 120x120mm(4 3/4"x4 3/4") with wall thickness 8mm(0.315"). I was sceptical about using butt joint so I put a 15mm(5/8") steel plate between pipes. Now the pipes are welded with a fillet weld with the steel plate (at 90°, 45° and 135°). I'd like to hear some expert or practitioner opinion on how structurally stable welding pipes in such arrangement is with respect to flat pipe without any welds. The forces will act on the sides, that are just 20cm(8") from the three point hitch arms so the leverage is pretty small.

Thanks!

A properly done weld, whether a fillet or a butt, will be stronger than the parent material. This means that the weld itself will not fail before the parts being welded together fail. The weldment may fail at the weld/parent interface, with the weld bead tearing out, but this is unlikely in a properly welded and designed structure. When making a butt weld on pipe or tube there should be 100% penetration of the weld from the outside to to the inside. furthermore, there weld will bead will not be flat but will be above the surface. So the weld bead will be thicker than the parent metal. Furthermore, the weld rod will be of a higher strength than the parent material. So if you are making proper welds a fillet weld is not necessary to replace a butt weld for strength.

 

[Sberry]