compression springs with 300ksi+ ultimate tensile str? 2

[danlee]

I know that music wire (ASTM A228) has an ultimate tensile strength of ~250 ksi at a .140" diameter. I'm hoping to make a compression spring of that diameter using a material with a higher tensile strength.

Does anyone have any experience making springs out of maraging steels or Aermet alloys? Can it be done? Or does anyone have any other material suggestion for making a compression spring with 300+ ksi tensile strength?

Thanks.

 

[TVP]

The latest generation of Cr-Si-V spring steels have a tensile strength of ~ 300 ksi (2070 MPa) for a diameter of 0.140 in (3.56 mm). ASTM A 1000 - 99 refers to this alloy as Grade D. The SAE nomenclature would be SAE 92V60 (V stands for vanadium). The quality of this wire is intermediate to commercial quality and valve quality, so high cycle fatigue strength may be lower than valve quality due to more inclusions and larger allowable seam depth. If you do not have a spring vendor yet, I highly recommend Associated Spring. They have their own internal standard/designation for this grade called AS-50.

Aermet and maraging steels are obvious candidates for spring applications due to their extremely high strength. I am unaware of any spring applications using Aermet (either alloy 100 or 310) but some aerospace spring manufacturers have made springs using maraging steels. I would recommend trying out the first option I mentioned before experimenting with these alloys. Good luck.

 

[israelkk]

You could use PH17-7 CH900 which is a littlr bit stronger at this diameter, minimum 258ksi per ASTM A 313-95a.

You still may could make the spring with Music wire. Did you considered preseting the spring, etc.

If you can send me your problem description I can look at it and may find a solution. I am the author of an expert system for mechanical spring design and during the last 30 years I designed hundereds of all kind of spring for commercial and aerospace use.

http://www.webspawner.com/users/israelkk/

 

[unclesyd]

Take a look at Rocket Wire at the following wedsite

http://www.mjwire.com/mjw_rocket.html

 

[ubergeek]

Hi, This is a bit longwinded but...
I'm not sure where I can get this information but could anyone help me? I'm trying to put a calc together that will consider the stress at the working deflection and at solid length (worstcase). From SRAM I got the range 49-70% of material UTS. Is this correct?
If so do you know where I can get a list of standard wire dias versus UTS of Music Wire ASTM A228?
Also...(told you it was longwinded)...if I use the formula for coil growth
D^2+d^2+(p^2-d^2)/pi^2
how can I take account of different wire dias and material properties and thermal expansion?
Hope you can help,
cheers

 

[israelkk]

ubergeek:

There are more than 50 common/standard types of wire spring from all kind of metals which can be generally devided into the following groups:

1. PATENTED AND COLD DRAWN CARBON STEEL
2. HARDENED AND TEMPERED CARBON AND LOW ALLOY STEEL
3. AUSTENITIC STAINLESS STEEL
4. PRECIPITATION HARDENING (AGED) STAINLESS STEEL
5. MARTENSITIC STAINLESS STEEL
6. COPPER ALLOYS
7. COPPER BERYLLIUM ALLOYS
8. NICKEL ALLOYS

You can collect information from SAE. AMS, ASTM, MIL-STDS, FED-STD, Internet etc. But note that for most wire materials the UTS is a function of the wire diameter but they can not easily compared by behavior to Music Wire.

The Associated Springs co. design handbook 1987 speeks of 35% to 50% of material UTS as the maximum shear stress.

On page 31 it gives:

O.D.(at solid)=SQRT(D*D+(P*P-d*d)/(Pi*Pi))+d

D=spring mean diameter with no load
d=wire diameter
p=coil pitch
Pi=3.1416...

The spring outside diameter at no load=D+d
The difference O.D.-(D+d) is what you are looking for.

As you can see the wire material properties do not play a role in the diameter change.

http://www.webspawner.com/users/israelkk/