I am entertaining a request for 15-5PH .062"diameter x 36" TIG weld wire. The base metal is 15-5PH and customer will not use 17-4PH as the weld wire. I have the wire drawing equipment and dies to take down the .26" diameter starting stock. I see 15-5PH Solution Ann has 8% Elongation min. but H1150 has 15% Elongation min. This martensitic stainless looks to be a real problem with its low elongation and being cold drawn.
I want to do this as a R&D project.
I have written a pass schedule with 20% RA between anneals. Can this be done?
Afraid I can't help with the drawing feasibility, but I suggest taking a look at H1150M condition if ductility will help. It yields a softer condition than H1150.
The procedure is:
Given that this is weld wire that's going to be re-melted and therefore attain new properties in service anyways, all you're really concerned about in this application is maximizing ductility for the wire drawing process so I would look into doing this in either the solution annealed or SA + overaged condition (I've seen overaging protocols between 1175 - 1275F). I pose both options because I can see how there might be a double edged sword with overaging in that, although it will soften the structure, you'll get some amount of austenite reversion which may then convert back to untempered martensite during the drawing operation and hurt your ductility in its own right. I don't have enough of a background in cold work to comment on how problematic this would be but it's something you can look into. If you're re-heat treating between every pass then that risk would be mitigated though.
You state that your drawing schedule would be 20% RA between anneals, but what is your drawing schedule? The PH Stainless Steels work harden very rapidly, so there would be a difference if you were drawing in a single hole machine or multi hole machine per pass. I can tolerate 30% RA in a pass for 15-7 PH Mo and 17-7PH before anneal if there are multiple draw dies per pass.
We would be using one die on a drawing machine as one pass before annealing. Nice to see 30% has been done.
20% on a single hole would be pushing the material too much in my opinion. We can achieve 30% reduction (and higher depending on the schedule), but I think 20% on a single draw might be too much. We typically use 4 reductions in line, with smaller reductions along the pass. The higher work hardening coefficient of the PH stainless steels helps with minimizing the elongation between the draws to help minimizing localized "necking" of the material.
I would not be afraid of drawing the 15-5PH four, 20% RA, passes between "anneals". I do not believe there is any reason to solution anneal; a 1450F (two hour?) "stress relief anneal" would give the material adequate ductility for wire drawing.
So, you might draw four passes from 0.260" to 0.161". Anneal. Draw four passes from 0.161" to 0.100". Anneal. Draw four passes to 0.062".
------------------------------David CoulstonNiles MI------------------------------
------------------------------David KirchnerCOOHigh Performance Alloys, IncTipton IN(765) 945-8230------------------------------
I agree. Four reductions per pass then anneal. Then do a "subcritical" anneal to remove drawing stress. Final question: "What is the final heat treat (if any) for this material?".
------------------------------David CoulstonNiles MIOriginal Message:Sent: 06-01-2023 10:02From: David KirchnerSubject: Does anyone have suggestions to cold work 15-5PH in wire drawing.
The material will possess "reasonable" stiffness after the final cold drawing. No final heat treatment is required.
Being used as weld wire, I intend to just leave 20% cold work and no further Anneal or Aging at my side. Suppling .062" Dia x 36" cut lengths for filler material on 15-5PH material. Customer would have to heat treat the welded fixture after the weld.
This has been an interesting discussion which I have come to just now. I don't have any experience with cold working the PH grades, so cannot contribute to that aspect. I do find it curious that the final customer is going to weld 15-5 and won't allow 17-4 as a consumable. The main reason for the development of 15-5 was that 17-4 has a tendency to form ferrite stringers, which reduces toughness particularly in the transverse direction in wrought products. Otherwise the two grades have fairly similar properties. But within a weld there is no alignment of microstructure from rolling, so no selective reduction in toughness from ferrite. I'm wondering if a specifier is unaware of these considerations. It is possible that they have some experience with 17-4/ type 630 welds and have had problems, we don't know these details. But on a quick search I found nobody offering a 15-5 consumable, while 630 is on offer in wire. This suggests a lack of demand for 15-5 consumables. Given the difficulties described in multi-pass drawing and multiple anneals, I would at least ask a supplier if they could produce a flux-core 15-5, but it may be such a small project that this isn't economical.
In any case a weldment will have to be designed to allow for property reduction below the standard heat treatment condition (strength as well as corrosion and SCC resistance) in the heat affected zone, and substantial variation throughout the weld zone with its overlapping HAZ's. Or the entire assembly will have to be re-heat treated to reach a desired heat treat condition and uniformity. A weld procedure qualification test would certainly seem to be called for. This would also allow for assessment of variation in the final weld after any loss of alloy content during arc transfer. A final option would be design for lower strength at the joint and use a lower strength non-matching stainless.
The starting stock is 15-5PH ESR annealed.
.260" - 130UTS 96Yld 40%El
Draw to .232" 20% -143UTS 137Yld.
Draw to .190" 20% -151UTS (test broke outside gage)
Next is to either stress relive or overage. We will try both test in a simple oven and retest strengths.
Full solution anneal is 1900F, but is still too strong.
H1150-M is 1400F 2Hr, 1150 4Hr. but takes too long in oven time.
Got an opinion on the shortest stress relief time and temp?
15-5 PH and 17-4 PH are nearly identical.
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