Welding of Solid Members

[seaw]

In practice, is it possible to weld two pieces of solid section (Fy=360 MPa) 250x150 mm. together on site ? If yes, is there special care for this case?

Thank you in advance.

 

[Metalguy]

I think it can be done with "vertical mold welding" (Linde Unionmelt) if the plates/sections are vertical. Otherwise you'll want to use sub-arc-with a LOT of passes!

 

[CWIC]

I personaly would not mention a technical response unless I had more details what you are trying to accomplish such as:

1.) What position is the joint in? (Some processes are limited by position including the 2 previously mentioned)

2.) Environmental conditions? (high wind or moisture present?)

3.) Many materials have a mechanical property range you specified, could you be more specific? (The type of material may determine which process is the most practical)

4.) You mentioned on-site, does this mean they are in-place? (If so, is high joint restaint in your considerations?)

I have a few more ?'s, but you could help resolve your problem by providing a bit more info.

Good Luck.

 

[seaw]

Thanks Metalguy and CWIC. Here are the additional information.

1.) These two pieces are aligned vertically as the following picture.

|| <--- Top member (first piece,
|| already connected to other members)
||
-- <--- Welded joint
||
|| <---- Bottom member (second piece,
|| no restraint to this member )
||

2.)Environment condition for relative humidity say 70%. This is 10 metres above ground basic wind speed here for return period 50 years around 33 metre/second

3.) Material grade is ST52-3 (DIN18800).I don't know the chemical compound and how to equivalent to US standard.

4.) Position on-site of member approximately 10 metres above ground.

Please give me the roughly idea is fine. I have to research more by myself in details.

Thanks.

 

[seaw]

The above picture (1) is elevation.

 

[seaw]

I'm sorry, actually meterial is GS-20 Mn 5,DIN18800

Chemical compound :

Carbon 0.17-0.23 %
Silicon <=0.60 %
Manganese 1.00-1.50 %
Phosphorus<= 0.02 %
Sulphur <=0.015 %
Chromium <= 0.30 %
Molybdenum <= 0.15 %
Nickel <= 0.40%

 

[CWIC]

What is the root opening of the members (the gap between the 2 parts joined)?

You can bevel the upper member and use a single bevel groove weld. The bottom member is a &quot;shelf&quot; where the weld is deposited upward along the groove (beveled) face.

 

[sayee1]

CWIC's recommendation of single bevel, if the thickness is 150/250mm, it would be better to use Double bevel. You can also use a double vee with bevel of ~15 Deg on lower plate and bevel of 30 Deg on upper plate. The 250mm*150mm dimensions are the length and width of plate(s)????? What is the thickness of the plate(s)???? 1.If the length of the plate is 250mm, it would be diificult to do SAW using the horizontal girth welder that the tank fabricators use.
2.The material shows some Cr,Mo and Ni % indicating the strength might be higher than a plain C-Mn steel. In that case I am not sure if you have FCAW-SS wires to match the composition/Mechanical properties, but you could check up with Lincoln. FCAW-SELF SHIELDED (innershield) process :30 miles/hr (48 km/hr) Based on Manufacturer's (Lincoln)Recommendation, so wind velocity not a problem, even if the wind speed increases you can always install wind breakers.

3.FCAW-GAS SHIELDED (‘dualshield’) process : 5 miles/hr (8 km/hr) Based on AWS D1.1, again wind velocity not a problem, but check on suitable consumables with manufacturer's.
For both the FCAW processes, the maximum torch length would be around 2.5 m, and the wire feeder to power source cable another 2.5m, so you may need to move the welding power source and wire feeder up so that there is not too much voltage drop because of the cables.

4. Again, the simplest method is of course the SMAW(Consumables should be the easiest to source), but understandably, since you want to improove the deposition rate, you may want to consider using larger diameter electrodes upto 8mm size, and further consider productivity by using two welders simultaneously from both sides of the plate.
Note that the processes I have listed are in the order of preference I would use based on whatever I could understand of the application.

Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668
End of all knowledge is the attainment of immortality!

 

[CWIC]

I concur with sayee on the double bevel joint configuration. I mentioned a singel bevel as the sketch shows arrows on one side only (not knowing if there is access to both sides of the joint). More good comments from sayee.

 

[seaw]

Thanks for all.