Magnetic Stainless for Spring? 1

[ajensen]

Hi All,

Can anyone tell me what grade of stainless steel can be used for a spring (curved spring washer) and will have magnetic properties?

Thanks!

 

[btrueblood]

Most 400 series stainless steels will be ferromagnetic after forming and heat treatment (if any). 440, 430 are typical ferritic grades stainless steels.

300 series s.s. will likely be weakly ferromagnetic after cold forming, 302 ss is an example. These can typically be rendered non-magnetic again with suitable heat treatment, but may soften as a result.

Some (most?) precipitation-hardening grades will be magnetic, 17-4 PH is an example.

Google for data sheets.

 

[EdStainless]

Any of the martensitic 400 series stainless grades.
All of the PH stainless alloys are strongly ferromagnetic after aging to high strength.

You could use a cold rolled duplex stainless (S32205) if you needed better corrosion resistance than any of the above. Not quite as high of strength, and not fully ferromagnetic, but close.

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Plymouth Tube

 

[ajensen]

Thanks guys. And do the grades you've listed above qualify as "spring steel"? Would they be appropriate to use for something like this:

http://seastromwashers.com/SpringWasherPricingRequest.aspx?productNumber=5804-166-2

 

[btrueblood]

Any would work. Again, even 302ss would have some magnetism in hard-condition cold rolled sheet. The biggest choice becomes what environment you want the washer to live in. High temperatures are ok for most 400 series stainless, but more corrosive, wet environments might make you pick a PH or 300 series ss.

 

[israelkk]

If you are looking for a magnetic stainless steels qualified as a "spring steel" you probably should go with 17-7PH condition C and after forming the washer heat treat it to CH900 condition.

 

[swall]

With 17-7 in condition CH900, it depends. The material is not as strongly magnetic as low alloy spring steels. You encounter problems trying to mag particle inspect 17-7 CH900 springs because of this. What is the reason for needing a magnetic material?

 

[TVP]

As the others have noted, there are a number of magnetic stainless steel options that are used in high strength, spring-type applications. Here is some information from Sandvik on their products:

Stainless steels for springs

http://www.smt.sandvik.com/sandvik/...A003A2055/$file/S-3411-ENG_02.pdf?OpenElement

Stainless chromium steel for razor blades

http://www.smt.sandvik.com/sandvik/...01369/$file/S-3332-ENG 021210.pdf?OpenElement

Strip steel for flapper valves

http://www.smt.sandvik.com/sandvik/..._Sandvik_S-343-ENG_214x300_C3.pdf?OpenElement

 

[ajensen]

What about a 1075 or 1095? I've seen theses grades in McMaster spring stock. Are they comparable to 17-7 or 302?

http://www.mcmaster.com/#spring-steel-shim-stock/=c9hivo

 

[swall]

No, those are carbon steel. Magnetic, but not stainless.

 

[ajensen]

Thanks so much for all the help, everyone.

 

[NickE]

go Sandvik, as TVP says, their 7C27Mo2 strip is rather magnetic, decently corrosion resistant, and will provide a superior fatigue life when finished properly.

There is definately a premium for their steel, they do provide large amounts of data, and if you are not looking for their performance advantages, common production grades will work fine... 420, 17-7, 301 (spring temper) are all good for curved spring washers that need to be magnetic.

Nick
I love science!

 

[blacksmith37]

To keep it simple (cheap), see what is available in cold rolled 316, it will be strongly ferromagnetic.

 

[dgallup]

316 is not cheap and it has about the lowest permeability for the amount of cold work of any of the common 300 series stainless steels.

 

[monkeydog]

Does anyone have a B-H curve for 302 CRES full-hard?

 

[blacksmith37]

Reading the post, are we trying to say "belleview spring washer" ?If so, a number of listings on the "net"; some list 301/302 -17-7 as std material. Not as ferromagnetic as 316 but still "magnetic".
Never measured permeability, etc, but cold worked 316 is not easy to differentiate from carbon steel with a strong magnet- that's what I mean by ferromagnetic.

 

[israelkk]

blacksmith37

You probably mean bellevile spring.