Looking for cost effective stainless steel

[pdybeck]

I am looking for a stainless steel that has a minumum yield strength for all round bar sizes of 60,000 psi. The material must be non-magnetic. I know there are some options out there, but I am looking for the most cost effective one considering both purchase price of the material and machinability. Thought I would float it out there to see if anyone has a good suggestion. I have some quotes out for Nitronic 50, but I suspect the pricing might be considerably higher than something like 303 (current material being used).

Pete

 

[EdStainless]

The Nitronic types of alloys are you best bet. There are other 200 series stainless grades that have enough Ni, Mn, N and Cu that they will stay non-magnetic when cold worked.

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[pdybeck]

Any info about relative cost? Are they in the ballpark of say a 303 material? Or are they much more?

Pete

 

[EdStainless]

They will cost less than 303, they have less Ni. 303 has very poor fatigue properties, so you would gain there.

Why do you only use 60ksi yield? Would higher strength help?
Too bad you need non-magnetic, a lean duplex would work in the annealed condition.

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Rust never sleeps
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[pdybeck]

60,000 psi yield was a strength level that was designed to on some of the prodcuts we manufacture. 303 in larger sizes becomes harder to locate (sometimes impossible) at that yield strength level. Larger sizes just can't be cold worked to that level. The material is used in motor rotor shafts, and with this particular design the material needs to be non-magnetic for performance reasons (and yes I know that 303 becomes slighlty magnetic when cold worked). I've noticed the reduction in Ni with the duplex materials, but we just can't have the magnetic properties that they have. Good news about the costing of Nitronic 50 relative to 303. It should also have a lower mamgnetic permeability than 303, even after its cold worked. Thanks for the reinforcement of what I thought was a good avenue to pursue.

 

[TVP]

Nitronic 50 has higher amounts of nickel than does Type 303: 11.5-13.5 for Nitronic 50 vs. 8.0-10.0 for 303. I believe that Nitronic 50 will be more expensive than Type 303 for a given bar size.

 

[pdybeck]

Anyone have any idea of how much more Nitronic will be... 10%, 25%, 50% .... I am trying to get a ballpark idea.

Thanks.

 

[pdybeck]

How about 316 per ASTM A 479 in the strain hardened condition? I can find magnetic permeability in the annelead condition but not the strain hardened condition. Anyone know if the magnetic permeability would be similar to strain hardened 303? Looks like it has roughly the same amount of nickel as Nitronic 50. Does 316 machine similarly to Nitronic 50, less, better? Is it possible to easily obtain 316 in the strain hardened condition even in shaft diameters up to 3inches?

 

[TVP]

Complete wild a55 guess: Nitronic 50 will be >30% more expensive than Type 303. HP Alloys or similar should be able to give you exact numbers.

 

[EdStainless]

I should have been more clear, I wasn't thinking of Nit50 specifically. There are a lot of Mn substituted grades with lower Ni content than 303/304. Alloys like S20153, S21062, S20200, S21460, S24000 are some examples.

This will be frustrating for you. I know that many of these alloys are only manufactured in some product forms and/or sizes. You will have to hunt to find options. Just make it clear what your property requirements are and you should be fine. (minimum yield strength, minimum elongation, maximum magnetic permiability).

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Rust never sleeps
Neither should your protection

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[TVP]

I agree with Ed-- look for the high Mn alloys in the 2xx series.

 

[pdybeck]

Examples per ASTM A276 would include XM-28 and XM-29 correct? Do you know if these typically come in sizes up to 3 inches in diameter? I have seen mechanical data for sizes up to 1 inch, so it makes me wonder. Are these materials commonly out on the market in round bar? Thanks for the help.

Pete

 

[TVP]

Yes, those are exactly the type of alloys we were mentioning. You should contact Carpenter or Universal Alloys as a starting point. They can refer you to other distributors, etc. if the quantities are small.

 

[pdybeck]

From the quotes I just started to get back, I am seeing that Nitronic 50 is about 3X the price per pound of 303. This would be unacceptable for us. I have yet to see a vendor that carries the XM-28 and XM-29 material in round bar. I am starting to think that these materials are not really furnished in round bar. I would think if they were, then pricing would be less than the Nitronic 50, as they contain much less nickel. I seem to be at a dead end right now with this material evaluation.

 

[EdStainless]

I know that there is a lot of '201' in various grades with about 4% Ni made as sheet and plate. I am not familiar with long products.

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Rust never sleeps
Neither should your protection

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[mcguire]

Cold worked 201, 1/8 hard. Nothing else is close.

Michael McGuire

http://stainlesssteelforengineers.blogspot.com/

 

[pdybeck]

Carpenter has 18Cr-2Ni-12Mn, which is XM-28 per ASTM A276. The prices are slightly higher than 303, and may be acceptable for us. Thought I would pass this along...

Pete