Buttering 1

[3lilaggies]

Don't really know if this is the best place to post this question but here it goes. Doing a 316 SS overlay onto Carbon steel is it nessisary or required to do a 309 SS overlay for buttering purposes? Tring to stay withint the limits of ASME section 8 and 9 for pressure vessels.

 

[metengr]

Yes, I would recommend it. Typically, the 309 stainless steel filler metal has an alloy composition that would reduce susceptibility to cracking in and adjacent to the fusion zone from martensite. Normally, martensite will form by dilution of an austenitic stainless steel filler metal (like 308, 316, etc.,) with carbon steel. Once the butter layer is applied with 309, you can overlay this with 316.

 

[gr2vessels]

3lilaggies,

All depends on the cladding method used;- you can overlay in one single pass a layer of 316L in an electroslag strip welding process. Typically you get up to 5 mm thickness with min. 3 mm undiluted 316L overlay (for shell and heads plate) or you can opt for 2 pass weld overlay for the nozzle neck interior and flange facing, or nozzle penetrations. Again, the 309 filler is an option and recommended, but not esential. Depending on your application, you would rather require some ferrite counting for the outer layer (refer API RP 582).

Cheers,

gr2vessels

 

[pvesseleng]

3lilaggies,
If you are using FCAW method, I would really recommend you for prevention of crack as metengr mentioned

 

[weldtek]

Suggest you consider 309Mo