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GMAW - CO2 Solid Wire Welding Uphill or Downhill

08/17/2013 3:04 AM

I want to weld 25mm thick carbon steel plates with 10mm fillet with vertical construction. I am using GMAW - Co2 solid wire methode for welding. I have approch to weld from top to down as well as down to top. The finish in top to down to very good with consistancy. The finish in down to top is not good, no control on crater. Which methode will be mechanically strong uphill or downhill. Pl suggest

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#1

Re: GMAW - Co2 solid wire welding uphill or downhill

08/17/2013 3:15 AM

Either one will work, if your person doing the welding is qualified.

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#2
In reply to #1

Re: GMAW - Co2 solid wire welding uphill or downhill

08/17/2013 3:56 AM

Yes the person doing welding is Qualified. I want to know which method will be mechanically strong.

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#3
In reply to #2

Re: GMAW - Co2 solid wire welding uphill or downhill

08/17/2013 6:02 AM

Hi prshjse,

I am not an expert in welding technology but as the previous responder said "either will work" vertical down or vertical up should be equally as strong as each other.

The "finish" would depend on the skill of the welder, as much as anything.

Best regards,

John

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#4
In reply to #2

Re: GMAW - Co2 solid wire welding uphill or downhill

08/17/2013 10:10 AM

If the person doing the welding is really qualified to do the job, they should know the answer, without asking strangers.

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#5

Re: GMAW - CO2 Solid Wire Welding Uphill or Downhill

08/17/2013 10:43 PM

IMHO, vertical down hand (starting at top) will potentially be less strong as there is the danger of 'cold lapping'.

Although vertical up hand (starting at bottom) may not look so pretty, it is more likely to produce the stronger weld and it is fairly easy to have consistancy of weld.

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#6

Re: GMAW - CO2 Solid Wire Welding Uphill or Downhill

08/17/2013 10:56 PM

Guaranteed the vertical down weld (top to bottom) will be prone to cold lap (which is a problem to be especially watched for in the mig process) and will not be as strong as the vertical up (bottom to top) weld. A good welder can make a vertical up weld look outstanding but it does take a lot of practise. This is the difference between a welder and what we call a "wire burner". I can't think of a single code or standard relating to the type of work you have mentioned that would allow a vertical down weld because of the reason listed above. Also you should be using a Ar/CO2/O2 mix for that thickness plate to provide good penetration, lack of inclusion, cut down on spatter. Straight CO2 for that type of work would not only look terrible but would also be prone to all sorts of welding defects.

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#9
In reply to #6

Re: GMAW - CO2 Solid Wire Welding Uphill or Downhill

08/31/2013 7:02 AM

What, Co2 will not if used properly. It will give the best penitration of about any of the gases.

Co2 is a reacitve shielding gas. You can go to the Lincoln electric web site and pick up the Shielding Gasses for GMAW paper they have produced that explains what happens when it is used while welding carbon steels. You will find that is is far better then most other gases for producing high quility weldments due to it's chemical reaction in the weld process.

Injoy the read.

Fixitorelse

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#10
In reply to #6

Re: GMAW - CO2 Solid Wire Welding Uphill or Downhill

09/20/2013 9:01 AM

AWS D1.1

3.7.1 Vertical-Up Welding Requirements. The progression for all passes in vertical position welding shall be upward, with the following exceptions:

(1) Undercut may be repaired vertically downwards when preheat is in conformance with Table 3.2, but not lower than 70°F (20°C).

(2) When tubular products are welded, the progression of vertical welding may be upwards or downwards, but only in the direction(s) for which the welder is qualified.

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#7

Re: GMAW - CO2 Solid Wire Welding Uphill or Downhill

08/18/2013 4:59 PM

This fellow says uphill welding is stronger, better penetration.

http://www.weldingtipsandtricks.com/mig-welding-techniques-uphill-welding.html

I am a rank amateur, a "wire burner". My uphill looks like it was splatterred on (being polite) with often too much crown. Downhill looks great. I can tell uphill burns in better. I sometimes finsih with a downhill to improve the appearance. - Probably bad technique.

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#8

Re: GMAW - CO2 Solid Wire Welding Uphill or Downhill

08/19/2013 8:50 AM

The 2 most difficult weld positions are VERTICAL and OVERHEAD!

Your welder should know how to do the weld and do it correctly, which would be a travel pattern from bottom to top.

C02 as the shielding gas will work fine.

A weld that will have more penetration and strength would be FCAW.

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Beej50 (1); fixitorelse (2); GW (1); jesw55 (1); lyn (1); Original_Macgyver (1); prshjsh (1); sanweld (1); techmad (1)

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