Dissimilar Welding

[Paolo.I]

I have to weld a T-joint in full penetration with dissimilar thicknesses in Asme IX. Both materials are in carbon steel (P-N.1.2) the only QW that speaks of dissimilar thicknesses is QW-202.4.
Base material 1 thickness 8mm
Base material 2 thickness 35mm
the QW-202.4 for the CS refers to the QW-451.1 for this case.

how do i prepare the two flaps for the qualification? should i follow ASME VIII-1 Figure UW-9? I tried to design the qualifying heels but I don't like it. I should taper the thickness difference to 96mm! it seems to me too much to qualify.
do you have any advice?
thank you!

 

[david339933]

Why not just weld a coupon with two plates of 35mm/2 minimum thickness? That would qualify for 5mm - 2x the thickness used.
Example: Weld a coupon with P#1 - 3/4" (19mm) Plates. Will qualify 5mm - 38mm. Both your thicknesses are within this range, so QW-202.4 is satisfied. Then taper as per construction Code in production.

Note: You say Base material 2 thickness is 35mm, but sketch shows 40mm.

 

[Paolo.I]

thanks for the reply, I did not specify that I am in the QW-403.6 impact test regime (The minimum base metal thickness qualified
is the thickness of the test coupon T or 5/8 in.)(16 mm),. Actually I wanted to qualify higher thicknesses, and the QW 202.4 says that with MB greater than 38mm the thickness is unlimited.
for this reason I put 40mm. the drawing you see is the Cupon that qualifies.

 

[david339933]

How about doing a coupon with the plate at 1-1/2", test it with no impacts. This will qualify 5mm - 200mm Base metal. Then do a coupon with the 8mm plate and do only impacts...all other variables the same as the first coupon. QW-403.6 only limits the min. thickness. Combine these two PQRs into one WPS with 8mm - 200mm qualified thickness with impacts.

 

I've always found it to be one of the more confusing rules in Section IX.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[r6155]

Test coupon for qualification of T-joint between 8mm and 35mm is the same as 8mm and 400mm.

Regards