Advice on A519 Weld Parameters

[tc7]

Our shop has been ordered to produce some special pipe fittings for a HP hydraulic application. The material is ASTM A519 grade 1045 or 1050 annealed condition.

The engineer has applied ASME B31.1 and/or B31.3 welding reqt’s. I am certain this customer has applied these without knowing much about either Code, but such as it is I am bound to qualify a new weld procedure. The ASTM A519 fittings will be joined (buttwelded) to A106 Grade B, 4”NPS Sch 80 pipe.

The high carbon content of 1045/1050 has me concerned and am uncertain of what an appropriate post weld stress relief, if any. I expect my general WPS to look like this:
GTAW root using 80s-B2 or B2L
SMAW fill using 8018-B2L or B3L
Open butt with Backing gas or backing ring (not sure which at this moment)
Preheat: 350-400 deg F
Interpass: 600 deg F
Stress relief: 1100 degrees for 30 mins

Key questions if you please:
1. If stress relief is necessary, does it matter if the welds cool too room temperature before pwht? I may not be able to get weldments to a high temp stress relief quickly. Comments please.
2. Not sure why I am selecting 80x wire and rod other than to match strength of the Gr1045 fittings.
3. Why do you suppose AWS B2.1 does not list A519 grade 1045/1050 but it does list other heat treatable alloy such as A519 Grade 4130?

Thanks again for all ideas & comments.

 

[metengr]

tc7;

1. If stress relief is necessary, does it matter if the welds cool too room temperature before pwht? I may not be able to get weldments to a high temp stress relief quickly. Comments please.

PWHT must be performed because of the increased carbon content in 1045 CS. No, cooling to RT is permitted provided low hydrogen wire or weld rod is used.

2. Not sure why I am selecting 80x wire and rod other than to match strength of the Gr1045 fittings.

Agree