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Music wire (ASTM A228)
Music wire is high-carbon steel spring wire, 0.70–1.00% carbon, cold drawn to ASTM A228. It has the highest tensile strength of the common spring wires, about 300 ksi (2,070 MPa) at 0.062 in (1.6 mm) and higher in finer sizes. It is the default for small compression, extension and torsion springs. It rusts bare, so plate, oil or coat it.
- UNS
- K08500
- ASTM
- A228
- SAE
- J178 (music steel spring wire)
- JIS G3522
- SWP-B (piano wire)
How does it compare?
Typical room-temperature values for Music wire, against all 48 materials in the library.
- Tensile strength
- 2070 MPa100th pct
- Density
- 7.85 g/cm³72th pct
- Max service temp
- 120 °C41th pct
- Relative cost
- $$$$$
Bars are relative to the strongest, densest or hottest material in the SSG library. Percentile vs all 48 materials.
- Density
- 7.85 g/cm³ · 0.2836 lb/in³
- Tensile strength
- 2070 MPa · 300.2 ksi
- Elastic modulus
- 207 GPa · 30.0 Msi
- Hardness
- Rockwell C41–60 (varies with diameter)
- Max service temperature
- 120 °C · 248 °F
When should you use Music wire?
Strengths
- Highest tensile strength of common spring wires, from about 230 ksi at 0.250 in to over 400 ksi in fine sizes
- Consistent quality and good fatigue life for cyclic springs
- Low cost; available from 0.004 to 0.250 in (0.10–6.35 mm)
- Coils and forms well on CNC spring coilers and fourslides
Watch for
- Maximum service about 250 °F (120 °C) before springs relax
- Rusts quickly; needs oil, plating or coating
- Plating creates hydrogen embrittlement risk; bake within hours of plating
- Not made above 0.250 in (6.35 mm); use oil-tempered or chrome-silicon wire
Typical parts
- Compression springs for switches, latches and pens
- Extension springs for doors and mechanisms
- Torsion springs for hinges and latches
- Clips and wire forms
- Instrument and small valve springs
How Music wire is made into parts
Cost, finishes and design rules for each process in this material.
What does a part in Music wire cost?
A representative part, springs & wire forms. Raw material at about $5.00/kg is one line of it; process time and tooling usually matter more.
Compression spring · Springs & wire forms
Order total $1,282
- Tooling
- None
- no hard tooling
- Piece price
- $0.11
- before setup + tooling
- Lead time
- 1–3 weeks
- to first production
Size
Drag a row to adjust · click to type
Wire diameter1.201.20 mm
Outside diameter12.012.0 mm
Free length40.040.0 mm
Quantity
Price per part falls as volume rises
Exact quantity1000010000 pcs
Material
Music wire (ASTM A228)
Design checks pass
Open in builderBudgetary estimate for a representative part. Firm quotes come from principals after drawing review.
Music wire questions
What is the maximum temperature for music wire springs?
About 250 °F (120 °C). Above that, springs relax and lose load. Chrome-silicon wire (ASTM A401) runs to about 475 °F (245 °C), 302 stainless to about 550 °F (288 °C), and nickel alloys beyond that.
Music wire vs stainless spring wire?
Music wire is roughly 15% stronger and costs about half as much, but it rusts. 302 stainless resists corrosion and heat to about 550 °F (288 °C) and has a lower shear modulus (10.0 vs 11.5 Msi, 69 vs 79 GPa), so the same design gives a softer rate.
Do music wire springs need heat treatment?
Yes. After coiling, springs get a low-temperature stress relief, typically 450–500 °F (230–260 °C) for 20–30 minutes, to stabilize dimensions and raise the elastic limit. It does not harden the wire, which is already hard from drawing.
Can music wire springs be zinc plated?
Yes, but plating charges the steel with hydrogen. Bake per ASTM B850, typically about 375–425 °F (190–220 °C) for 4 hours or more, started within 4 hours of plating, to prevent delayed embrittlement failures.
Quote it in Music wire.
Upload CAD or start from a template. The builder prices it in this material and the alternatives.