Less ferrite in Super Duplex
Less ferrite in Super Duplex
(OP)
Hi,
I want to qualify a super Duplex PQR in UNS S32760 grade material, Currently I am using mock up piece of 3" sch 80 UNS 32760 & welding with GTAW process with ER2594 filler wire having shielding & backing gas as Ar+2% N2.
I am getting ferrite of 46% in root pass & 36% in hot pass, in subsequent passes ferrite is dropping to below 30%. I have maintained interpass of max 100 Deg C & heat input between 0.8 -1.2 kJ/mm. Project spec ask to use 2% N2 for shielding & ASTM G48 test is required in PQR with 35-60% ferrite in weld.
For a changer when I used pure Argon (99.999%) for shielding I am getting ferrite of 43-46% in weld.
.Is there any relation of gas mixture with respect to ferrite, again I have been advised that to pass ASTM G48 test 2%N2 mixture is must. So I am confused how to get the required ferrite & to pass the ASTM G48 test. A quick response is highly appreciated.
I want to qualify a super Duplex PQR in UNS S32760 grade material, Currently I am using mock up piece of 3" sch 80 UNS 32760 & welding with GTAW process with ER2594 filler wire having shielding & backing gas as Ar+2% N2.
I am getting ferrite of 46% in root pass & 36% in hot pass, in subsequent passes ferrite is dropping to below 30%. I have maintained interpass of max 100 Deg C & heat input between 0.8 -1.2 kJ/mm. Project spec ask to use 2% N2 for shielding & ASTM G48 test is required in PQR with 35-60% ferrite in weld.
For a changer when I used pure Argon (99.999%) for shielding I am getting ferrite of 43-46% in weld.
.Is there any relation of gas mixture with respect to ferrite, again I have been advised that to pass ASTM G48 test 2%N2 mixture is must. So I am confused how to get the required ferrite & to pass the ASTM G48 test. A quick response is highly appreciated.





RE: Less ferrite in Super Duplex
http://www.nickelalloys.com.br/Metrode%20CD%202011...
RE: Less ferrite in Super Duplex
RE: Less ferrite in Super Duplex
249.8 gm/m2/day.This result is awful, I welded the cupon with root & hot pass with 2%N2+ Argon as sheilding & backinng gas, rest of the passes where welded with Argon as shelding gas & 2% N2+Argon as backing gas for 8 mm thickness.
Heat input was maintained bewtween 1-1.2Kj/mm & process used was GTAW with filler as ER2594.Can any body give more insight to pass the above test.
RE: Less ferrite in Super Duplex
RE: Less ferrite in Super Duplex
May I ask what amps, volts, travel speed you are recording to obtain above values?