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Stainless steel 302 (spring temper)
302 stainless is an 18-8 austenitic stainless steel with slightly more carbon than 304, drawn to spring temper per ASTM A313. It is the most common stainless spring wire, with about 250 ksi (1,720 MPa) tensile at 0.062 in (1.6 mm). It resists rust and holds load to about 550 °F (288 °C). Use it where music wire would corrode.
- UNS
- S30200
- ASTM
- A313 Type 302
- EN 10270-3
- 1.4310 (X10CrNi18-8)
How does it compare?
Typical room-temperature values for 302 SS, against all 48 materials in the library.
- Tensile strength
- 1720 MPa98th pct
- Density
- 7.92 g/cm³87th pct
- Max service temp
- 288 °C83th pct
- Relative cost
- $$$$$
Bars are relative to the strongest, densest or hottest material in the SSG library. Percentile vs all 48 materials.
- Density
- 7.92 g/cm³ · 0.2861 lb/in³
- Tensile strength
- 1720 MPa · 249.5 ksi
- Elastic modulus
- 193 GPa · 28.0 Msi
- Max service temperature
- 288 °C · 550 °F
- Melting point
- 1400 °C · 2552 °F
- Thermal conductivity
- 16.2 W/m·K
When should you use 302 SS?
Strengths
- Corrosion resistant in water, humidity, and most food and medical environments
- Service to about 550 °F (288 °C), more than twice music wire's limit
- No plating needed, so no hydrogen embrittlement risk
- Passivates for medical and food-contact parts
Watch for
- About 15% lower tensile strength than music wire in the same size
- Lower shear modulus, 10.0 Msi (69 GPa), so springs are softer for the same geometry
- Mildly magnetic after cold drawing
- Costs roughly twice as much as music wire
Typical parts
- Compression and extension springs in wet or outdoor service
- Medical device and food equipment springs
- Marine hardware springs
- Wire forms, retaining clips and battery contacts
- Pump and valve springs
How 302 SS is made into parts
Cost, finishes and design rules for each process in this material.
What does a part in 302 SS cost?
A representative part, springs & wire forms. Raw material at about $9.00/kg is one line of it; process time and tooling usually matter more.
Compression spring · Springs & wire forms
Order total $1,444
- Tooling
- None
- no hard tooling
- Piece price
- $0.13
- 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
Design checks pass
Open in builderBudgetary estimate for a representative part. Firm quotes come from principals after drawing review.
Finishes
302 SS questions
302 vs 304 stainless for springs?
Chemistry is close; 302 allows more carbon (0.15% vs 0.08% maximum), which gives a little more strength after drawing. Most spring wire today is dual-certified 302/304 to ASTM A313, so the choice rarely changes cost or lead time.
Is 302 stainless magnetic?
Annealed 302 is essentially non-magnetic. Drawing to spring temper transforms some austenite to martensite, so spring wire is mildly magnetic. For truly non-magnetic springs, use phosphor bronze C510 or beryllium copper.
Do stainless springs need heat treatment?
Yes. A stress relief after coiling, typically 600–800 °F (315–425 °C) for about 30 minutes, raises the elastic limit and stabilizes dimensions. Passivation afterward restores full corrosion resistance.
When should I use 17-7 PH instead of 302?
17-7 PH stainless (ASTM A313 Type 631) is precipitation hardened after forming for higher strength and better relaxation resistance to about 650 °F (343 °C). Use it for high-stress stainless springs; 302 covers most general needs.
Similar materials
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