Charpy impact testing requirements

[engr2GW]

Hi,

when the anticipated temperature (ambience or media) in an oil and gas facility is not going to go below -20F is Charpy impact testing required for the weld procedure?
1. For API wellhead welding to ANSI line pipe, MDT above at -20F
2. Same as 1 above but MDT below -20F
3. B31.3, 31.4, or 31.8 piping with MDT above -20F
4. Same as 3 above with MDT below -20F

I am under the impression from my little knowlege of the code that impact testing is required only for 2 and 4 above, is that right?

If so, how does one determine the test temperature?

Thanks a lot.

 

[engr2GW]

@ stanweld;

does that mean that per table 323.2.2, the weld metal and HAZ (basically the welding) should only be impact tested only when MDT is below -20F right?

As much as possible, do it right the first time...

 

[stanweld]

Generally speaking, no. See Note 3 of Table 323.2.2. In your case, I would suspect that the stress ratio is > 0.3 in Fig. 323.2.2B and impact test qualification of your welding procedure at -20 F would be required if you defined the MDMT at -20 F.

 

[engr2GW]

what I'm understanding is that I would have to qualify my procedures with impact testing at the MDT I chose or less than the MDT. Now, since from figure 323.2.2A with regards to material, the MDT goes up with thickness above 0.5", my questions are:
1. If I qualify my procedures with Charpy at -20 or whatever the MDT is set as, that the figure stated above for mateial apply, in other words, does higher thickness where the material MDT is higher than -20 pose a problem or is the welding of that pipe good for any thickness/
2. I have seen procedures with 6010 and 7010 for field stick welding, I don't think they'll be good for less than -20, can you recommend any good electrode for root and fill/cap for lower temperature
Thank you.


As much as possible, do it right the first time...

 

[stanweld]

You can always impact test qualify a WPS at a temperature lower than mandated under the curves but remember that the thickness range for qualification can well be more restrictive under B31.3 than under ASME IX.

You can make the root with GTAW with ER70S-2 or -6 and the fill passes with 7018 to easily meet -20 F, B31.3 impact requirements. You should also purchase your A-106 B and API 5LX pipe with -20 F impacts.

 

[engr2GW]

Thanks,

If my MDT is -20F, i though the 6010 7010 comibation are qualified down to -20F for impact properties (absorbed energy ft-lb), can I not use those?

also, when I rule a straight line on the curve in figure 323.2.2A, the MDT for A106 ceases to be -20F at about 0.55 or higher, not 0.5. Is it generally considered 0.5 from a conservative stand point?

As much as possible, do it right the first time...

 

[AndyVictor]

Sorry to post this after long gap.

Actually my doubt is on comment by Vesselfab(Sept 2011) that "don't forget that your weld consumables must be certified for -20F"

Is the requirement to be certified(Can be done by consumable manufacturer) or classified (expected to be classified by specification/standard/code)


As per UCS 67, weld is exepted from Impact test, if:
1. Material is exempted and
2. Welding consumable is classified by impact testing at a temperature not warmer than MDMT by applicable SFA specification.

Can any one guide me to how to find whether a given electrode/filler wire is classified by impact testing as above? (eg: ER70 S6, E7018, 80 S Ni1)I could see the following in the SFA5.1/18/28:

E7018-1 : Table 3 Charpy impact test requirements give a value of 27J@ -45 deg C

ER70S2 : Table 4 impact test requirements give a value of 27J@ -30 deg C

ER 80 S Ni1: Table 4 impact test requirements give a value of 27J@ -45 deg C

Does this mean that these consumables are classified by impact testing at a temperature (145, 130 deg C )as required by code(UCS 67)?

Thanks

Andy