how many weld passes does it take? 2

[tweedledee]

Hi,
Does anyone know of a table that would tell me how many passes it would take to get a weld of various sizes?

I.e. how many passes for a 1/2" weld,.. and how many passes for a 5/8" weld.. etc...

I'm an engineer and I spec welds all the time, but havent (until now), given much thought to the poor sod doing the welds.

Thanks

 

[dbooker630]

It depends on the wire size, wire class, the material to be welded, the end-use application as a minimum to consider. Some joints require multiple-pass welds to minimize high hardness areas in the heat-affected zone. Selection of wire, MIG tends to be hotter than flux-cored. Some wires such as Innershield are meant for high productivity welding but that has to be balanced against desired penetration.

 

[metengr]

The link below is a part of a welding handbook by ESAB. It might provide some guidance as to deposition rates in lbs per linear foot of weld deposited based on fillet weld size, and for groove welds

http://www.weldcall.com/EUWeb/MIG_handbook/592mig9_3.htm

 

[csd72]

In my understanding, welds up to 1/4" are possible as single pass welds (but as mentioned above it depends on the type of rod used e.t.c.).

Larger welds would be proportionate to the weld volume which is proportionate to the leg length squared. so by this theory 3/8" is two/three pass, 1/2" is a 4 pass e.t.c.

If the fillet weld ends up larger than 1/2" then I would normally use a butt weld instead as it is usually cheaper.

csd

 

[GRoberts]

Try getting a copy of "The Procedure Handbook of Arc Welding" By Lincoln Electric. It has all sorts of information like this on various joints, processes, and positions, and is cheap. You can get it from the Lincoln website.

 

[henri2]

GRoberts, can't someone get a copy of that book free with AWS membership?

 

[GRoberts]

Nope, (not as far as I know), as it is not an AWS publication. You can get a copy of the AWS welding handbook for $15 (I think) with a new membership.

 

[unclesyd]

Here is another good book with the information you require.

"Design of Weldments" by Omer Blodgett (Lincoln Electric)

This is the Lincoln Electric website mentioned above and the source of many inexpensive technical references.

https://ssl.lincolnelectric.com/lincoln/apdirect/store.asp?PID=16&cat=8

 

[7Mark]

Rather than trying to estimate how many passes are required to produce a given size weld, you might be better off estimating the time it will take to make the weld. First, calculate the weight of the weld. Then divide that by the deposition rate of the process to be used. You may have different estimates of the deposition rates but the ones I've used successfully are:
Stick welding........... 2 lb/hr
Mig welding............. 5 lb/hr
Submerged Arc welding... 10 lb/hr

The deposition rate for submerged arc welding takes into account the increased setup time to use that method. Those are rates for skilled welders.

 

[tweedledee]

Thanks you all for the very informative answers,

T

 

[zcp]

AWS D1.1 Table 3.7 has good information for maximum root pass, maximum fill pass, and maximum single pass fillet weld sizes.

For example (from d1.1:2002....it was handy)....maximum single pass fillet in flat position for smaw is 3/8 in. For gmaw/fcaw it is 1/2 in. For the overhead position, this goes down to 5/16 in for both.

Maximum fill passes are 3/16 in for smaw and 1/4 in for gmaw/fcaw.

These are for prequalified WPS.

ZCP

http://www.phoenix-engineer.com