HAZ Hardness Problems 316L Overlay 4130
HAZ Hardness Problems 316L Overlay 4130
(OP)
I have done about 5 coupons/tests on this procedure and cannot seem to get the HAZ hardness better than 5-10 too hard in Vickers (255-260).
We are using pulsed TIG machines.
0.2/0.2 high/low
50% background current
~270 amps
0.9 inch Z step per revolution
400-500F preheat
7-10 IPM travel speed *table*
~80 IPM wire feed speed
After welded we wrap it up and cool down.
Does anyone have an idea of where to go from here? We are conforming to NACE/API/ASME.
We are using pulsed TIG machines.
0.2/0.2 high/low
50% background current
~270 amps
0.9 inch Z step per revolution
400-500F preheat
7-10 IPM travel speed *table*
~80 IPM wire feed speed
After welded we wrap it up and cool down.
Does anyone have an idea of where to go from here? We are conforming to NACE/API/ASME.





RE: HAZ Hardness Problems 316L Overlay 4130
Gas composition could be an issue, too, but I would check the preheat, first.
rp
RE: HAZ Hardness Problems 316L Overlay 4130
RE: HAZ Hardness Problems 316L Overlay 4130
RE: HAZ Hardness Problems 316L Overlay 4130
Are you sure you are dealing with straight 4130, or has it been modified with extra Mo, extra Cr, or perhaps some V? If it's been modified, you might have problems.
A postheat operation may sensitize the 316, so be careful.
rp
RE: HAZ Hardness Problems 316L Overlay 4130
Does anyone know if my settings are near correct?
RE: HAZ Hardness Problems 316L Overlay 4130
RE: HAZ Hardness Problems 316L Overlay 4130
RE: HAZ Hardness Problems 316L Overlay 4130
I have another option for your consideration - why don't you use a butter layer of 309 over the 4130, PWHT the 4130 to have the hardness where you need to be and complete the weld joint using 309 stainless to 316 to avoid sensitization?? Seems like a better way to go versus all of the above. In lieu of 309 you can use Inconel.
RE: HAZ Hardness Problems 316L Overlay 4130
RE: HAZ Hardness Problems 316L Overlay 4130
If you cannot get vermiculite, get a hot topping agent , commonly used in foundries.
RE: HAZ Hardness Problems 316L Overlay 4130
RE: HAZ Hardness Problems 316L Overlay 4130
Let us know what you ended up doing.
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There is always some thing better out there...
Mahadhatu
RE: HAZ Hardness Problems 316L Overlay 4130
Using a high Ni stainless butter layer, PWHT, and then overlay is the safe way to do this.
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Plymouth Tube
RE: HAZ Hardness Problems 316L Overlay 4130
If a specific max hardness was required post-weld in the HAZ of this thick section 4130 part, wouldn't it have been a good idea to make sure the 4130 part was in the appropriate HT condition prior to welding?
RE: HAZ Hardness Problems 316L Overlay 4130
We were sort of following what the suggested/recommended PWHT ranges were in their specifications. I am new to this industry and welding in general. Will cooking it at this lower temperature help with the HAZ hardness?
The temper is at 1202ºF and we are cooking 1175-1190 per suggested spec.
I don't think for the application we are using that using a different wire to butter will be acceptable. If it comes to that I will check out that solution.