What are the most suitable welding methods for filling an elliptic cavity with a rib on its center

[johnnyBronny]

Hello All,

In the company I am working in, we want to manufacture internally reinforced structures. We found out the best way to do this was to cut each individual part and then weld the joints. I am new to welding, so I would like to know if it is possible to weld two surfaces that are almost in contact with each other (0.05 mm). I know I can use spot welding, but the size of the parts is small (15*20*2 mm is a rough estimate), so I don't think it is possible. What are the most suitable welding methods for filling an elliptic cavity with 25*1.5 mm with 1 mm height that has a rib belonging to other plate with dimensions 17*1*1 on its center?


Thanks

 

[kingnero]

Can you post a picture?

the most suitable welding method is likely the welding method you have at hand, as new welding techniques inherently come with a learning curve.
If you need to start from scratch, there are a number of possibilities, both at this point the description is not enough to work with.

 

[johnnyBronny]

Hi,

Thanks for the reply. I am posting a picture. I would appreciate if you could get into detail about the several possibilities along with important factors, such as cost, or, alternatively, to post the reference of a book on this matter. What I am specially concerned with is the very small distance between the two surface at the 4 corners of the rib (0.05 mm). I would appreciate if someone could indicate the best welding method considering this constraint.

Thanks for the reply,
Johhny

 

[kingnero]

That is not what I had in mind with your description, but I see it now.
I do believe that the rib from the bottom part is an inconvenience. Do you need it for accuracy/alignment between both parts?

Material is mild steel?

Spot welding is a possibility, this is not the smallest I've seen that has been spot welded.

For welding of parts this small, I'd wait for someone with hands-on micro-TIG, EB or laser welding experience.
Regular (gtaw/TIG, GMAW/MAG or stick welding) processes will all melt both parts together, but probably not as clean as you will want to. a "regular" bead width of these processes starts at +/- 6 mm. You want to fill in the cavity with the rib, which is 1.5mm width. So I suggest to wait for welding experts experienced in this kind of weldments.

 

[johnnyBronny]

Hi,

The material is a low alloy steel. The rib from the bottom surface is to make possible the welding of places of difficult or even impossible access. This is only a very simple model. In fact these patterns will be incorporated in complex geometries and the last surfaces to weld will need this arrangement, as some zones may be impossible to access.

Can you post the reference of a book in this matter? I would appreciate any ones that explains in a practical approach how to select the best welding method, including important factors for selection, etc..

What do you think about the issue I am concerned with? Is is possible to weld such small distances, as the rib corners to the elliptic cavity walls, such as in this case. The distance between those two is only 0.05 mm.

Many thanks for your help!
Johnny

 

[tbuelna]

Thanks for the picture. But I'm still confused by what you want to achieve with the weld. In the OP you stated you wanted the weld to fill the elliptical cavity, which cannot be achieved simply by melting the center rib as shown. You would need to add some filler metal. To make things easier, is there any reason you cannot modify the shape of the rib to match the elliptical hole so that an automated TIG or laser process can be used to fuse (butt weld) the perimeter. Even if there is a small gap it would not be a problem to fuse the parts to the full thickness of the plate, and it would just leave a slightly depressed surface at the weld location.

 

[hendersdc]

Any particular reason you have an elliptical slot? For welded sheet metal parts where I use tabs and slots to aid in fixturing I have rectangular slots that are oversized by about 0.010" in the length and width (0.005" gap all around). I keep the tab height at about 50% material thickness and then fill the rest with a plug weld.