Impact testing of Wear Plates

[david339933]

Hello,

If a vessel to be fabricated needs to be impact tested (materials), does the material for the saddle wear plates also need to be tested?

Also if I am using SA-516-70N material for the shells/heads, does the repad material for nozzles also need to be Normalized?

 

[SnTMan]

Double postng is generally discouraged.

 

[gr2vessels]

david,
The saddle wear plate is subject to the same temperature conditions, since it is welded directly to the shell. As such, it has to be impact tested, as required the shell. Also, the same PWHT is required for the assembly of shell/wear plate or at least the wear plate shall be normalised, just like the shell material. Good news however, you don't need to normalise the saddle base plate.
Cheers,
gr2vessels

 

[vesselfab]

Why would the wear plate be required to b normalized?

If the wear plate is thinner than shell, it may not be required to be impact tested.

All parts should be evaluated individually.

 

[gr2vessels]

The comp pad is welded to the shell and nozzle neck. The edge is highly stressed and the weld can crack under low temperature operation. The strength of a comp pad is in the weld to the neck and the edge. You loose the edge, the pad is a floating decoration and the nozzle fails in operation. You will need a stress relief treatment for the low temp operation. Either normalised material or PWHT.

 

[vesselguy]

All parts welded directly to the shell/head needs to be of the same grade and material as the parent shell/head. Hence if a new vessel is PWHT then the entire vessel except for the 'attachments' shall be completly PWHT together.

 

[weldtek]

UG 84(a) makes me think differently when it comes to wear pads. Unless you determine that wear pads are 'subject to stress due to pressure' they may be exempt.
UCS66(a) goes further in saying ' attachments which are essential to the structural integrity of the vessel when welded to pressure containing components'. Does a saddle wear pad fall into this category. Of course each case must be evaluated by a competent engineer, but, I don't think one can say that impact tested material must be used in every situation.
The same goes for normalized material.
Clarifying, I'm talking about minimum Code requirements.