coil spring material

[powers2b]

Reverse engineering a coil spring for an aerospace application.
Mat'l report came back with the following % by weight;
Fe-49
Ni-44.83
Mo-3
Ti-2
Al-1
Cu-0.12
Mn-.10
C-0.02
Si-0.02

Any specific reason for the addition of Ti, Al?
I haven't found a material vendor that can identify the material.
Any help Mat'l I.D or with vendors that deal with special materials would be appreciated.

 

[israelkk]

It seems to be a Nickel alloy however, it doesn't match the common nickel alloys such as Monel, Inconel and Ni-span. It will be helpful if you can point out where it was used. Is it from an American product?, European product? East Europe products, etc. It will also be helpful to know the working environment of the spring (temperatures, etc.).

It is not simple to reverse engineer a spring even if you have the correct material. You can not just make a spring with identical dimensions. You have to know what metallurgical and mechanical processes the spring had. It may had a preset at room temperature or other temperature etc. You should calculate the stresses, fatigue cycle etc., and know the working conditions to successfully reverse engineer the spring.

http://israelkk.googlepages.com/home

 

[powers2b]

Thanks for the reply.
This is for a US based supplier to a US based aircraft company.
I am leaning towards having a second analysis done at another lab to confirm the material composition as none of the spring material vendors I have contacted are familiar with the material.

 

[CoryPad]

Addition of Ti and Al would be to form intermetallic particles like Ni₃(Al,Ti). These increase the strength of iron- and nickel-based alloys.

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[powers2b]

Thanks CoryPad
Are you aware of a material that has a similar chemistry?

 

[CoryPad]

No. Ni-Span is close. You can use MatWeb's composition search function to see what is close:

http://www.matweb.com/search/SearchComp.asp

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[TVP]

powers2b,

Make sure that there is not a nickel coating on the wire that is compromising the analysis. Nickel coating is frequently used to act as a lubricant/reduce friction on stainless steel and other spring wires during the coiling process. What is the wire size? Do you know exactly how the analysis was performed, meaning how the sample was probed, what analytical method/equipment was used, etc.? This may be helpful for choosing a 2nd method.

 

[powers2b]

Thanks all for the helpful hints and suggestions.
CoryPad; The Matweb site is great.

 

[jackpot]

The amount of chrome was curiously left out of your material report. Ni Span 902 is the best fit but it has nominally 5.25% Cr.

Have a lab recheck the material for Cr.

Jack

 

[powers2b]

Sorry Jackpot,
Cr-0.02

Chemistry was verified by second lab.