welding L-80 casing to 4130

[cjgrass]

We need to develop a welding procedure for welding L-80 Type 1 casing to cone shaped for lack of a better term "end caps" of 4130 material. the pipe and cones are 13.375" x 0.375". my greatest concern is the PWHT that would be required after welding. design temperature is -50F to +250F. design code is ASME B31.4. hydro test pressure will be 5500psi, operating pressure will be 2600psi. there will also be L-80 to L-80 welds on the piece will they also require PWHT? if anyone good give me some tips on this i would be greatly appreciative or if i more information is needed please let me know. thank you

 

[metengr]

What welding process and filler metal are you considering? What is the heat treat condition of the 4130?

The L-80, Type 1 casing appears to be a heat treated, carbon steel (0.43%C by mass) material. The carbon content is such that welding should require PWHT to ensure adequate ductility in the heat affected zone of the L-80 casing material. This means PWHT temperature, if required, needs to be below the original tempering temperature by 50 deg F to avoid altering the bulk casing mechanical properties.

The 4130 can be welded with no PWHT given the thickness and lower carbon content. So, the limiting factor will be the L-80 casing.

 

[cjgrass]

We are considering GTAW root & hot pass SMAW fill and cap, ER80S/E8018B2L or C3. the 4130 is N Q&T. The MTR for the L80 shows 0.30% C, tempering temperature of 1150F. thank you

 

[metengr]

The 0.43%C by mass was a maximum so your casing material is well under this limit. I would select a PWHT temperature of 1080 to 1100 deg F for PWHT and this would probably not affect the N&T, 4130 material bulk properties. Qualify a WPS with supplemental hardness testing.

 

[cjgrass]

Thanks a bunch for your time and expertise. what would you consider the maximum acceptable hardness range to be for these materials? we will be using Vickers HV10.

 

[metengr]

250 Vickers.