Flexable arm spring

[grayseal]

We are trying to reverse engineer a flexible light arm with a light attached to it.

The arm is made in three sections. Each section is made from three strands of coiled wire separated by a triangular shaped wire. The smallest section is made from .101” diameter wire, the next .126” diameter, and the last from .136” diameter wire.

I believe this wire is made from ASTM A229, Steel Wire, Oil Tempered for Mechanical Springs. The chemistry matches, the mechanical properties match, and the microstructure is tempered martensite.

My problem is with the triangular shaped wire. Shown below is the chemical analysis:

Element (wt%) Upper Middle Lower
Carbon 0.05 0.04 0.05
Manganese 0.28 0.31 0.34
Phosphorus 0.015 0.008 0.019
Sulfur 0.018 0.011 0.012
Silicon 0.10 0.10 0.10
Nickel 0.06 0.50 0.10
Chromium 0.08 0.10 0.11
Molybdenum 0.02 0.02 0.02
Copper 0.16 0.17 0.21
Vanadium <0.005 <0.005 <0.005

I can’t match it to any standard, mostly because of the copper content. From my understanding, the wire starts out as round, formed into the triangular shape and lastly placed as a spacer between the coils of the other wire.

If you have an idea or can point me to someone who would, it would be greatly appreciated.

grayseal

 

[JoeyV87]

BS EN 756: S1

Your Mn is slightly low, but apart from that...

 

[grayseal]

Thanks JoeyV87,
I had only searched ASTM specifications for wire and never thought of looking at welding wire. It looks like a close match.
grayseal