ASME IX welding questions: techniques, variables, etc

[engr2GW]

Hi,
I have few questions
1. In ASME Section IX, it says the deletion of a backing is non-essential, I understand it to mean if the WPS was qualified with a backing and you choose to weld without one, you don't have to re-qualify the procedure, in the variable table for SMAW in QW 253, it does not say anything about addition of a backing, what if the coupon for PQR was welded without a backing, does adding a backing to the actual welding be an issue, or can the WPS be writting with/without backing?

2. I could not find anything on wether change in progression or combing progression is essential or not, the coupon was welded down-hill, can the WPS be written for up and down or just what the PQR says

3. ASME B31.3 stipuslates pre-heat requirements for ambient temperature under 32F and for certain thickness and tensile ranges. To raise the bar, can I choose to say ambient under 40F or 35F if I wanted?

4. Why is there not a voltage range/setting for SMAW as there are for GMAW and GTAW

Thank you.

 

[stanweld]

1. Yes

2. Can be written "up or down" but only down if impact test qualified.

3. Yes

4. SMAW uses Constant Current power supplies. Voltage is essentially not able to be controlled; it is primarily based on electrode type, diameter and current.

 

[DVWE]

Stanweld, I believe you meant "non-impact" tested for #2.

 

[DVWE]

Ahh,,,scratch that last post.

 

[DVWE]

In ASME Section IX, it says the deletion of a backing is non-essential, I understand it to mean if the WPS was qualified with a backing and you choose to weld without one, you don't have to re-qualify the procedure

You understand correctly. However, make sure your welders are qualified to weld without backing, as this is an essential variable for welder qualification. Ref QW-353

what if the coupon for PQR was welded without a backing, does adding a backing to the actual welding be an issue, or can the WPS be writting with/without backing?

Adding a backing bar is not an issue. You can write with/without in your WPS.

Why is there not a voltage range/setting for SMAW as there are for GMAW and GTAW

To add a little more to what stanweld posted, voltage is automatically controlled with the arc length in SMAW. The longer the arc length gets, the higher the voltage gets and vice versa.

 

[engr2GW]

My profound appreciation to all your inputs.

 

[Kiwi2671]

stanweld,
Do you mean for point 2 "if impact tests are required" ?
I am a bit confused.
QW 405.3 has change in vertical progression as a non essential variable.
If you decide to perform impact tests (and it is not a construction code requirement) surely you would still fall under QW 405.3 and could still write a WPS for vertical up or down ?
Regards,
Kiwi

 

[DVWE]

Kiwi,

Have a look at QW-405.2 That explains the vertical up and impact test relation.

 

[Kiwi2671]

DVWE,
I realise the clause in QW 405.2.
What I was questioning was the different terminology used in stanwelds response.
The supplementary variable (QW 405.2) only comes into play if my construction code requires impact testing.
Please correct me if I am wrong:
I qualify a PQR vertical down to ASME IX and I have it impact tested.
I can then write one WPS for vertical down or up for use where impact testing is not required by the construction code and one WPS for vertical down only where impact testing is required by the construction code.
Your thoughts,
Regards,
Kiwi

 

[DVWE]

I can then write one WPS for vertical down or up for use where impact testing is not required by the construction code and one WPS for vertical down only where impact testing is required by the construction code.

That is a correct statement. I don't want to speak for stanweld, but the OPs post uses a vertical down PQR, and I believe stanweld was responding to that.

 

[stanweld]

Kiwi,
I meant if impact testing is required under the design Code and the impact test qualification was made in the Vertical down progression.

 

[Kiwi2671]

Thanks Stanweld.
Apologies for seeming pedantic.
Just clarifying that you have the option of writing two WPS's if you have performed impact tests.
Regards,
Kiwi