Music Wire & Spring Wire Size Chart (ASTM A228)
Music spring wire (ASTM A228) diameters with their tensile strength range and modulus, from fine 0.10 mm wire to 6.35 mm.
| Diameter (mm) | Min. tensile (MPa) | Max. tensile (MPa) | Diameter (in) |
|---|
Standard: ASTM A228 / EN 10270-1 · Data checked: 2026-10-14
Frequently asked questions
Why does thin music wire have a higher tensile strength than thick?
Because cold drawing strengthens the wire as it reduces the section, and a thin wire is drawn through proportionally more reduction for the same final size. This is why the tensile range in the table falls from about 3000 MPa at 0.10 mm to about 1650 MPa at 4.88 mm.
What does the modulus mean for spring design?
Music wire is about 207 GPa in tension and 79 GPa in torsion. The torsional figure is the one you use for a coiled spring, because the wire is loaded in torsion when the spring compresses. Note that the modulus does not change with tensile strength, so a stronger wire is not stiffer — a stiffer spring needs a different geometry.
Can I substitute music wire for a stainless spring?
Not if corrosion matters. Music wire is high-carbon steel, so it will rust, which is why springs are usually plated or oiled. Type 302 or 316 stainless springs are weaker and lose strength at high temperature, so substitute by specifying the load and travel you need, not by matching the wire diameter.
What is the working temperature limit?
About 120 degrees C for music wire. Above that, stress relaxation accelerates and the spring loses load even without being compressed further. For hot environments, use a chrome-silicon or a stainless grade with a stated temperature rating.