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ASME Section VIII, Div. 1, Impact Testing for Welding Procedures to weld repair SA-352, LCC material

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newweldeng09

Mechanical
Oct 31, 2008
84
Hello,

I was wondering if someone can help me out with this scenario. I have a compressor case that needs a weld repair to fix some mis-machined dimensions. The MDMT is -20F and it has to meet NACE MR0175. SA-352 is exempt from impact testing to this Div. in accordance with Fig. UG-84.1, note c. Per UCS-66(j), -20F is the coldest temp. to be assigned to welded components that do not meet UCS-67(a)(3). UCS-67(a)(1) through (a)(3) do not apply in this situation because of the base metal and MDMT. So, the repair welding procedure does not have to be impact tested. Is this correct or am I missing something? It seems odd that the base material has to be impact tested, but the weld and HAZ in the welding procedure does not.
 
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I don't believe you have stated it correctly. The base material does not require to be impact tested at -20 deg F or higher, therefore, the weld or base metal HAZ do not require impact testing. The repair weld procedure would also not require impact testing because the minimum design temperature is -20 deg F.

As a side note, you are invoking Section VIII, Div 1 requirements on a compressor case?
 
The base material specification requires impact testing at -50f/15ftlbs min avg. In this case,regardless of MDMT, I think you need to weld with a procedure that meets the notch toughness of the base material. If you are using an E7018 or ER70S-2 or 3 filler metal you should have no problems. ASTM A352 takes you to A488 for repair welding and specifies that Cv notch tests of weld metal and HAZ shall be made on the weld procedure when such tests are required by the base material specification. I'd do them just to CYA.
 
jwhit;
The base material does not require impact testing based on Section VIII Div 1 requirements.
 
I agree that ASME VIII does not require it for the material and circumstances, but the actual material specification, ASTM A352 does require impacts as a part of the mechanical testing requirements. Temperatures may be varied from the -50f specified but I see nothing that totally removes the requirement. If this part was being fabricated to a component manufactured to a material specification without an impact requirement I would agree that it doesn't need to be done. In this case it is a repair weld on a component made to ASTM A352 LCC, the welding should meet that specification as well to satisfy ASTM A488. The heck of it is that the welding & any is going to be done exactly the same regardless of whether the case was A216 WCC or A352 LCC, so it's all splitting technical hairs.
Admittedly, I'm looking at it from the foundryman's side of things where our first obligation is the material specification and then meeting the additional specifications. In the last 42 years I've never seen an impact requirement removed or waived by a customer for any of the A352 materials, at least at our level in the food chain.
 
metengr-
We are building a compressor case to API 617. For repairs to fabricated cases, this spec. specifies that the repair has to be in accordance with Section VIII.
 
jwit;
I understand from your perspective that you are certifying the material for -50 deg F impact per the material specification, and rightfully so. This is an end user application, after certification, and if the code of construction exempts impact testing for -20 deg F and higher for end use, I see no reason to impact test for the sake of trying to consider this as a repair during certification of the casting. If this casting were to be used for Section VIII and was below the -20 deg F, impact testing would be required.

I view it once the material leaves your shop and is accepted for code use at -20 deg F or warmer as with other ferrous materials, no impact testing after material certification is required by the code of construction and in-service.
 
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