Material properties for Aluminium Bronze to NC Ashton 93/7 spec?

[rattler]

Hi,

We are being asked to manufacture a special stud which was originally made from Aluminium Bronze to "NC Ashton 93/7 Cu/Al + Tin + Cobalt". The material is no longer available. Does anyone know of a direct equivalent or have any mechanical property data for this material?

The stud is used in an application where it is subjected to shock loading.

Thanks.

 

[TVP]

Here is a link to the patent for this alloy, which shows the composition, heat treatment, typical properties, etc.:

http://www.google.com/patents/about?id=Mtx7AAAAEBAJ&dq=3979208

This alloy was optimized for cold forming with moderate strength and good toughness. UNS C61400 is somewhat similar, i.e. a 7% aluminum bronze, but it does not contain Co or Sn, and therefore is not a precipitation hardening grade. It can be cold worked to similar strength levels. If you don't need to cold form bar/wire to manufacture the stud, then perhaps a nickel aluminum bronze like UNS C63000 would be a suitable alternative. It can easily achieve similar strength with good toughness.

 

[rattler]

Thanks TVP, that's great. I do have a couple more questions however!

How do I relate the patent to the material spec called up on the drawing please? The patent doesn't explicitly state the "93/7 Cu/Al + Tin + Cobalt" wording.

Also the drawing of the stud does not contain any heat treat information or any requirement to roll the threads. The assembly the stud is fitted into has been physically shock tested in the past. The two alloys you've quoted have lower %elongation values than most of those given in the patent (UNS C63000 -10% and UNS C61400 -35%). I don't know how to quantify the effect of the property %elongation but my instinct is that a high ductility is a good thing when the component is subject to shock loading.

Can you advise please if the reduced ductility of UNS C61400 relative to the original material is likely to imply a reduced "shock resistance" compared to the original material and is it possible to quantify it?