strip passes TIG pipe girth weld

[Richard Smith]

Are strip passes considered good form when girth welding pipe -
V-groove - 5G (PH) ?
What are the "rules" for them?

Example would be a stainless steel pipe TIG weld around 22mm wall
thickness steel pipe therefore 20+ weld runs, can be good to get
things back to uniform height as approaching cap.

"strip passes" - part-circumference weld runs - not a complete pass.

[Ernie Leimkuhler]

In article <m0wqk9l...@unknown.home>, Richard Smith <nu...@void.com>
wrote:

Not sure about your terminology.
The only time you do continuous weld beads around a large pipe is when
it is on a rotator or on rollers.
In the field you are breaking up the weld passes as position and fit-up
require.
Also you don't usually switch from vertical up to vertical down on the
same weld pass.

[Richard Smith]

Hi Ernie - oops - completely messed up this one in the telling...

Trying again

No matter how you lay up the weld runs - 1G-rotated, 5G-up, whatever...
Suppose you would have 27 runs - but you've ended up with a sector of
the circumference which is less high than other parts (yes, for the
same number of runs they whould have filled the groove to the same
height, in an ideal world - but sometimes things are not so ideal).
So before you get the the capping passes you do say a layer which is
the full of the groove comprising several runs - but these runs go
only say half way around the circumference...

With the intention that entering the capping pass, you have a uniform
groove fill level - normally just below the pipe outer surface level.

So for one thing, that makes the number of runs in a pipe girth weld
difficult to represent in one cross-section.

Now I know you are so skilled that this never happens to you...
But it can happen to less experienced welders - you will have seen
this(?)

I gather part-circumference runs are known as "strip" or "stripper"
passes.


???

Rich Smith

[Ernie Leimkuhler]

In article <m0y54nt...@unknown.home>, Richard Smith <nu...@void.com>

I spend way more time inspecting pipe welds that running pipe welds.
Monitoring your overall weld bead height is just something you have to
keep track of. You can adjust your bead height by changing your travels
speed.
As an inspector I don't care how many passes you have in the groove.
I care what your root looks like, and I care what your cap pass looks
like.
On steam lines I will mag particle your root to look for cracks, and I
will mag your cap. If you have 23 passes on one side and 19 passes on
the other does not matter to the code or to inspection. That is a
personal thing, but is not important to whether or not your weld is
accessible.

[Richard Smith]

For some alloys - like duplex stainless steel or Ni-alloys - you are
tightly bound by your heat input and it would not be a good idea to
try to change bead height by significantly changing travel speed?
I have seen that with duplex you have to get going and stay going at
that speed you know you need...
Of course, different fill in different sectors of the circumference
means that you are making a systematic error going faster in one
sector than another (if speed change were random, the different bead
sizes would cancel eachother out(?)).

I note your point - for sure you cannot inspect how many runs there
are between root and cap for a production weld which cannot be
destructively tested (eg. section and macro-etch) - nor does it matter
metallurgically so long as you have always stayed within close limits
on welding conditions...

Thanks and best wishes

Rich