weld prep 10mm penetration.

[Warren]

Hello, I will apologies now for this post as I am a newbie in welding.
Could anyone point me in the correct way to prep single bevel without backing.
We have a 2 piece ‘T’ to fab up. All material is 20mm think.
Client is saying that a single weld prep of 10mm should be put on one side only on the vertical piece and give a weld symbol of s10. Is this correct? Would this not simply fill the welled prep up if prep and S is 10mm?
Cheers
Warren.

 

[storm monkey]

I may be wrong on this but, assuming the drawing shows a fillet weld, one side only, then by putting s as 10, you will get a fillet with 10mm leg lengths, and no pen specified. To ensure adequate pen, you'll need to specify pen as 1o also. Hope the below makes sense!

------------------------<
10 ||
10 |/

Also, unless you use a j groove, a 45 degree chamfer prep on one side, all the way through, will require twice as much filler as a 45 deg prep on each side.

Phil

 

[Warren]

I thought that if you had a fillet weld you could have a as the leg and s as the pen?
eg a8 s10
but what if the weld is a single bevel? what prep would it be?
The weld, like you say will use a lot of filler that's for sure.
I'm really not sure on this and it is hard to find a solution even with all the codes!
Warren.

 

[Drains]

Warren ,there are no hard and fast rules with weld prep - there are too many variables.

However, standard practice with a fillet is no prep at all, unless it's a large fillet, multi rums are required, and for any other reason complete fusion of the joint is required.

Penetration depth is not normally specified, though leg length is.

For your 20mm fillet a prep would not be out of order, neither would a 10mm leg, but this should be on BOTH SIDES of the joint. A 45 degree angle would be ok on the prep, and penetration should be more than half way through the joint to ensure complete fusion.

Alternative welds could be a 20mm leg from one side, with a j prep and penetration right through, or an un-prepped joint welded both sides with a leg greater than 10mm - I'd suggest 12-14mm.

You also should spec the voltage range. Have a look at the mig welding calculator

I've assumed you are using mig, mild steel, and a nothing special application...
Others may well have different opinions to me!

Good luck

Si

 

[snowcat]

Whats this for? and why is the client giving you a prep sequence? If you have a proper set of drafts drawings then it should be on it? It sounds like the client talking BS,

Single beval T is usualy for plates under 1/2"
Double bevel Tee is used in large stress joint sheer, lo/ude, traverse,
Single J heavy plate normaly 1" upwards
Double J very heavy 1 1/2" upwards,

I cant understand useing a single J on "small" plate, HD is going to be an issue with that much fill?

Can you not put a double V in, sounds like geting to both sides of the plate is not an issue?

 

[Hitch]

I dont see the need for any real prep is its a fillet weld.
Perhaps a 3/4mm chamfer on the bottom of the vertical piece, put a nice root run in, then lightly cut into the bottom of it, do another run on the lower side, then cut into the top of that and the top of the first weld. Do a third third run. Its a bit overkill, but will easily give you the weld size you require.

 

[irondarren]

Got to say im with Hitch a root run then a few overlays over the top would be good enough. If i was doing it, would be arc welded with a 3.2mm rod for the root, then 4mm rods over the top, to build up some thickness on the fillet

 

[Warren]

The clients weld symbol is a single bevel l/ with either a convex or concave face. The drawing is at work while im at home so i apologies. I dont think that the client wants a fillet that stands out but one that is flush with the leg.
l l
l l .\---------
l l ..\
l l ...\
l l ....\--------
l l

Another problem is that the webs come in pairs so i can only get to the outside edge so only one side.
All bloody good remarks from you all, thankyou, but is it the same for a single bevel?
I will apologies again for being a newbie.
Thanks again chaps

Warren

 

[Hitch]

I see now what your trying to acheive. is it possible to move the joint so its in a nice position to weld up? You will then get a nice smooth weld,with the bare minimum or even none of the leg protruding past the face of the vertical piece.

Not the easiest joint to do

 

[Warren]

I wish i could move the welds but ive just got the job to do weld prep drawings. I think youre right, this weld is going to be a nightmare.
Warren

 

[snowcat]

Oh choice warren, the problem is as im sure your aware is geting the flat face while in position,......Or get an apprentice to do it