Should i Simulate the future PWHT on my PQRT? 1

[bmoorthy]

Hello All

A 352 LCC Valve casting is found to have repairable defect.

Weld repair is planned.

The valve is Designed to ASME/ANSI B 16.34 which refers to ASME SEC VIII Div 1 for the purpose of the repair welds and ASME SEC XI regarding the Procedure Qualification.

The Valve manufacturer has ordered the casting on the foundry, and has specified that casting shall be accompanied by the material Test Certificate.

Now the WPS proposed(Supported by PQRT) by the foundry takes care of the Heat treatment. The soaking time at the PWHT temperature, are consistent with depth of the repair.

The valve manufacturer informs that, since the casting is going to be subsequently heat treated again, future heat treatment cycle has to be taken care of in the PQRT, therefore the PQRT specimen shall undergo additional simulated heat treatment.

The foundry informs that if additional heat treatment is done then the material certificate will not indicate that the material is A 350 LF2 because the material Spec A 350 LF2 dictates that the heat treatment of the casting shall be as per PQRT. Since the PQRT and the WPS is going to specify additional heat treatment and the Casting is going to be heat treated by the foundry for lesser time the material certificate of the casting cannot be A 352 LCC.

Is it necessary to simulate the heat treatments for PQRT when reparing Plates, Pipes, Forgings, Castings?

How does ASME address this issue?

I am sure many of the castings and large forgings as repaired and subsequently used in ASME applications, what does the ASME say about this.

 

[metengr]

No, future PWHT's do not need to be addressed once a component has been supplied to a Standard or material Specification. Weld repairs that are performed during fabrication of a casting are referenced in the particular material Specification or Standard, for example SA-217. Once the foundry has certified compliance with ASME SA 217, this is it.

The weld procedure used for the repair of the casting at the foundry should be qualified using ASME Section IX guidelines, and the heat treatment referenced in the material Specification or Standard. This is the only heat treatment that should be used on the WPQR.

Once the casting has been certified to the particular material Specification, any future weld repairs or PWHT or stress relieving will be in accordance with the Code of Construction or some other Construction Standard that will require a separate weld procedure, and referenced PWHT requirements.

 

[bmoorthy]

Thanks Metengr.
We did put this argument to the client. But he is slightly uneasy.How can i support my argument, is there some interpration. Say for plate or forging specification, if not in a casting?

 

[metengr]

Sit down with the client and carefully review the material Specification requirements, supplemental requirements (if specified) and, more importantly, Reference Documents in the PO. Once the foundry has certified that the component (casting or otherwise) has met the requirements of the applicable material Specification, it is out of their hands.

I have never seen it implied in any Code or Standard that one has to account for future weld repairs in a finished product.

 

[metengr]

This may also help;

Review ASME SA-703 Specification. This is one of the Reference Documents that pertains to General Requirements for Castings.

 

[jamesl]

I think the client is right.

According to SA-350, "when forgings are thermally treated after repair welding, the weld procedure test shall be subjected to the same heat treatment". The foundry can produce a new PQR to include subsequent HT.

 

[metengr]

jamesl;
What you state has already been stated above in the orginal post - "Now the WPS proposed(Supported by PQRT) by the foundry takes care of the Heat treatment. The soaking time at the PWHT temperature, are consistent with depth of the repair."

The argument as I understand it is any subsequent PWHT to the valve, after the casting has been certified to meet SA 350.

 

[GenB]

If the repair is according to the casting specification including the PWHT, the first PWHT is what it counts; the valve mfr should not have to heat treat again. my suggestion is that you submmit to them copy of PWHT documents so they will not have to ht again if their procedure calls for heat treat (ussually the PWHT temp and other parameters are the same as the heat treat used for castings), you are the foundry, you know that part) if the heat treat of castings is different, then you are in trouble,
and you may have to comply with the valve mfr,
they want to cover their part w/o expenses and if you have to run another test you are in the 500 - 1000 Dlls or more in expenses. plate/welding/2 heat treats/ 2 lab works
genb

 

[jamesl]

metengr,
My understanding is the same as GenB's.

The casting has not been certified yet since we are still talking about repair. Valve manufacture wants the foundry PQR for repair work to cover the heat treatment they (valve manufacture) are going to do on the piece after fabrication. The foundry does not want to do it because they have to produce a new PQR which will cost some money.

If the valve manufacture covers the cost of new PQR, I do not see any reason that foundry cannot certify the material to SA350.

 

[metengr]

I don't believe that the valve manufacturer wants to cover this cost, which is the reason for the post. The foundry should not cover this cost either.


What I find interesting is that the valve manufacturer SHOULD have the necessary weld procedures to handle this activity without having to rely on the foundry.

 

[SJones]

Firstly, can we all stop mixing material standard designations as it is getting confused as to whether we are dealing with castings or forgings.

Having done that, we need to be clear on whether the requirement to simulate a subsequent heat treatment in the qualification was specified to the casting supplier (along with the specific heat treatment procedure to apply)in the order. If not, it's an extra and the foundry has every right to request payment for so doing. Materials certificates don't enter into the discussion, particularly as the valve manufacturer will have to recertify the material after the planned heat treatment.

Steve Jones
Materials & Corrosion Engineer

http://www.pdo.co.om/pdo/

 

[GenB]

The foundry is in trouble because the casting was not perfect and need repairs,
to fulfill the weld repair, PWHT is to be performed.
If the casting was perfect no PWHT by the foundry was needed, so at the end the foundry is to cover for the problem.
This is a complicated business matter, now it is not Code related, but Who has to pay for what!!! What about getting some lawyers involved,
Are you in California? if not you are lucky
is it clear?
genb

 

[GRoberts]

It is confusing whether we are talking about LCC or LF2 because the original post mentions both. However, since the part was made by a foundry (instead of a forge) I'll assume we are talking LCC here. If the material is LCC, then CVN testing of the WPS is required at -50F. Since ASME IX requires that the test weld used to qualify the WPS be subject to at least 80% of the total time at temperature that the weld will see in production, I think that if the valve gets a subsequent PWHT, that the original PQR has to account for that. The smarter customers that I work with specify all of this up front, but the other customers always come back and ask if we happen to be qualified for the heat treatment they just put the part through that they neglected to tell us about in the beginning.

 

[bmoorthy]

My Mistake.
Instead of A 352 LCC, i mixed it up with A 350 LF2.
The intent of the query was regarding A 352 LCC and NOT
A 350 LF2.

However the query is applicable for all product forms.

To reword the query

Is it the intent of A 352, that the PQRT for welding repair take care of the future heat treatments which the item may under go after leaving the foundry?

 

[metengr]

This post seems to be more confusing as time goes on. The repairs to the casting are under the responsibility of the party (Supplier) that will certify the product to the specific ASME material specification. Let me try this angle

Question: Is it the intent of A 352, that the PQRT for welding repair take care of the future heat treatments which the item may under go? (I purposely left out foundry and valve supplier because this is a contractual issue not a technical issue)

Reply: Yes, SA-352 requires weld repairs to be performed in accordance with ASME Section IX. The organization that is responsible for weld repair and certification of the casting shall be responsible for all necessary PWHT on the PQR.

 

[GenB]

It is my understanding here that the Foundry did not do the certification before and that the valve mfr did because they were the ones performing the required casting heat treat. now the foundry problem is that they have to weld and after the weld repairs need PWHT, that PWHT triggers a secundary casting heat treating by the valve mfr, since the secundary PWHT is not at the same temperature the valve mfr requires a simulation of the secon heat treating,
(the foundry triggered/caused the priblem therfore the valve mfr wants the foundry to cover the cost- it make sense to me) but as METENGR says at the end it is a contractual problem and not a Code problem. The foundry wants to get away from thir mess by finding a way not to create a simulation of the second h"casting HT", which it may be inevitable.
it is a mess!!! I think that Codewise the simulation is needed and it is an expensive one, someone has to pay for.
I am out of this now. this has to end somehow.
Good Bye.

 

[bmoorthy]

Thanks all for the (Heat!!)Inputs