interpass temperature defintion
interpass temperature defintion
(OP)
our procedure defines weld pass as a weld bead extending the entire length of a longitudinal weld. The result of a pass is a weld bead and may include several stops and starts.
the procedure definition for interpass temperature as the maximum temperature of a section of the deposited weld metal and adjacent base material immmedialtey prior to welding again in that section for multipass welds.
The location for taking this temperature states 1" from the weld.
However, many of the welder take the deffintion of weld pass and interpret it to read that the temperature should only be taken between weld layers and only at those points. ie prior to root, prior to each intermediate layer and prior to final cover layer.
I believe it means that at no point shall the assembly be above this temperature.
the procedure definition for interpass temperature as the maximum temperature of a section of the deposited weld metal and adjacent base material immmedialtey prior to welding again in that section for multipass welds.
The location for taking this temperature states 1" from the weld.
However, many of the welder take the deffintion of weld pass and interpret it to read that the temperature should only be taken between weld layers and only at those points. ie prior to root, prior to each intermediate layer and prior to final cover layer.
I believe it means that at no point shall the assembly be above this temperature.





RE: interpass temperature defintion
interpass temperature: the highest temperature in the weld
joint immediately prior to welding, or in the case of multiple
pass welds, the highest temperature in the section of
the previously deposited weld metal, immediately before
the next pass is started.
The interpass temperature is to control the amount of heat into the weld joint, meaning the surrounding base material that encompasses the weld joint.
RE: interpass temperature defintion
You are correct. However, I would replace your word "assembly" with weld joint.
RE: interpass temperature defintion
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
RE: interpass temperature defintion
This is an interpretation from ASME IX
IX-83-161
Question: When interpass temperature (QW406.3) is a required supplementary essential variable for procedure qualification, must the interpass temperature be as specified immediately prior to each arc initiation ?
Reply: No. Interpass temperature shall be as specified immediately prior to the start of each pass.
AWS A3.0 defines a weld pass as a single progression of welding along a joint.The result of a weld pass is a weld bead or layer.
I do not know how to post pictures but for those of you who have access to AWS A3.0 have a look at Figures 23 (D) & (E)- they show details of weld layers.
Sorry to say diverdileo but your welders are correct.
Regards,
Kiwi
RE: interpass temperature defintion
RE: interpass temperature defintion
This is what you posted
"However, many of the welder take the deffintion of weld pass and interpret it to read that the temperature should only be taken between weld layers and only at those points. ie prior to root, prior to each intermediate layer and prior to final cover layer."
That is correct.
You also posted
"I believe it means that at no point shall the assembly be above this temperature."
That is incorrect
Regards,
Kiwi
RE: interpass temperature defintion
RE: interpass temperature defintion
layer: a stratum of weld metal consisting of one or more
beads. See figures QW/QB-492.1 and QW/QB-492.2.
pass: a single progression of a welding or surfacing operation
along a joint, weld deposit, or substrate. The result of
a pass is a weld bead or layer.
RE: interpass temperature defintion
A good example would be if you have a WPS with a listed maximum interpass temperature of 600F. You cannot start any weld pass if the weld joint is above that temperature, and you take the temperature immediately before the start of the next weld pass. Now, what if you take the temperature of the weld joint immediately AFTER a weld pass has been completed and the temperature is 625F?
Is that acceptable? YES.
Can you start welding before the weld joint cools to 600 or below? NO.
RE: interpass temperature defintion
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
RE: interpass temperature defintion
Interpass does not limit heat input, it is just the maximum temperature the plate can have before starting the next pass.
One problem with the temperature definition can arise when welding with high heat input (Q) on fairly thin plate, of a material where maximum temperature is an issue (e.g., duplex SS). The temperature during and just after welding can be extremely high and could still do metallurgical damage, even if the welder waits until it cools down before depositing the next pass.
This is another reason not to skimp on the size of PQR test plates, where the heat sink is a 'worst case' condition (i.e., very small).