Impact testing Ver. 2.0

[Chris]

Here is another question, dealing with procedure qualification impact testing reqirments.

Application is power station, elevated temp service, let say in this situation run of the mill ASTM A106 Gr. B, 9.53 mm W.T, buttweld, GTAW & MMAW. (question doesnt only apply to elevated service temps)

looking at the destructive testing requirements, specifically the impact testing.

I know what you are thinking, only for low temp service, thats the answer that i have consistantly recieved but lets put aside previous exsperences and common perseptions and only look at AS3992.

Table 6.1, Number of test specimens required for procedure qualification.

Note 10: "Impact tests on weld metal and HAZ are only required when specified in Table 7.2"

looking at Table 7.2,

Where impact test are required are split into "On weld Metal" & "On Haz" coulumns

Following the reference to AS4041 fig. 2.11.2(a) for weldmetal clearly shows the normal low temp requirements and certianly in this this application impact testing doesnt apply to weld metal or parent material.

But when looking at the tesing criteria for the heat affectected zone its is not so cut and dry, and here in lies my point

"Pressure vessels and piping, as for weld metal where the heat input exceeds 5 kJ/mm",

obviosly this will not appy in this combination of processes but it goes on to say………

"or where H/t (Note 4)exceeds—0.1 for preheat or interrun temperatures (eaqual to and less than) 100°C, or 0.08 for preheat or interrun temperatures >100°C, but heat input imits do not apply for normalized steels

Note 4: exspains that:    H/t = heat input (in kilojoules per millimetre)
                                            ——————————————————————–
                                            sum of parent metal thickness at weld (in millimetres)

filling in the blanks with general ball park figures the tig and the stick portions have little hope of being under the 0.8 H/t and in most cases impact testing will apply.

That is how i interperate the Table 7.2 and its notes but every time i look at a PQR for most jobs i have worked, neither the impact testing has been completed or the tighter essential variables (Postion, Thickness) have been quoted on the WPS.

Am i right in my interpretation of the code or is there somthing i have missed?

please forgive my spelling mistakes, as i cant find a spell check:P

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