Temper Bead PQRT 1

[tc7]

We have some cast steel valve bodies (ASME P No. 3) which have been weld repaired (not by us) and the valve has since been machined, heat treated and finish machined. The castings are ASTM A487 Grade 4 (similar to a 4130, but with a little less chrome). I have been asked to develop and qualify a temper bead weld procedure so that all further repairs may avoid any post weld heat treatment. Lot's have been written on temper bead so we understand the concept, but I can't really imagine what the PQRT would be. I suppose I would follow the typical groove weld procedure in plates of similar composition and Q&T strength value, then temper bead weld it and perform the same old typical tensile and bend tests with a Charpy thrown in for good measure? (I don't think a Charpy for this material would otherwise be required).

We think the cracks and indications on the previous repairs can be removed within a 1/2" deep excavation. I have considerd repairs with a high nickel tig rod (like maybe an Inconel 625), but will at least use an ER80S-B2 rod.

Looking forward to any advice on this and thanks.

 

[metengr]

tc7;
If you want to see how a PQRT is used for temper bead, see ASME B&PV Code, Section IX, QW-290. All of the information is contained in this section for guidance to qualify a temper bead weld procedure specification.

Hardness testing is probably more applicable versus CVN.

 

[tc7]

QW-290? I knew we should have bought the 2004 edition!!

Any thoughts on use of the Inconnel rod?
As far as you know, does the ASME Code permit us to select a filler with higher ductility but lower strength versus one with matching tensile strength values as compared to the base alloy properties? If so, am I correct in thinking the tensile tests will be pass or fail based on the advertised tensile properties of the chosen filler but the bend tests will be based on the properties of the base material 9to determine diameter of the mandrel)?
Thanks.

 

[metengr]

tc7;
Yes and yes. The Inconel rod (I would suggest Inco 92) can be used for qualification of the temper bead weld procedure. The minimum UTS is 80 Ksi.