Weld Repair Procedure- 25% Duplex Casting

[Vikas Bhandari]

Hi

I have a weld procedure which the manufacturer of valves wants to use as a repair procedure for contingency purposes for 25% Super duplex casting.The procedure conducts solution annealing after welding. I think , for repair (allowing minor repair only,no  more than 25% of wall thickness , not more than 10% of total surface area), localised solution annealing (1120 C) is neither possible nor desirable (more chances to form embrittle precipitates in the surrounding region). So the best solution is to weld (which will raise to temperature greater than 1120 anyways) the repair , followed by water quenching after completion of welding.

Please correct me if I am deviating form the facts.

Secondly, the proposed WPS shall be rejected as PWHT is not carried out in minor repair of 25 Cr Castings.

Your prompt response in this regard would be much appreciated.

Best regards 

[Pieper QSI]

Dear Mr. Bhandari,

 

Regarding minor repairs of Super Duplex Stainless Steel I would suggest to weld with a maximum interpass temperature of 150 °C.

 

One of my customers also manufactures Super Duplex Stainless Steel castings and as long as the part isn’t machined we prefer executing welding and afterwards perform solution heat treatment at 1130 °C followed by water quenching, but only for the full part and not local because of critical temperature areas as suggest by yourself.

 

After machining we only execute minor repairs by controlling interpass temperature with a maximum of 150 °C. In this way it’s not necessary to perform water quenching afterwards because the influence on surrounding material will be minimized. Of course manufacturer needs a qualified repair welding procedure for this because PWHT is an essential variable and testing need to include microstructure examination of HAZ and base material to ensure no precipitation takes place and/or sigma phase will be present.

 

Hope this will help you forward.

 

Met vriendelijke groeten / Best Regards

 

Herman Pieper

 

Pieper Quality Support & Inspection

Phone: +31 (0)521 380083

Fax:     +31 (0)84 7539225

Cell:     +31 (0)6 51691215

www.pieper-qsi.nl

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[ar...@iinet.net.au]

Vikas,

The option would be to anneal the whole lot again and water quench.



On Thu May 26 4:35 , Vikas Bhandari sent: