Through optimised composition control and processing, 304 stainless steel spring wire strikes a balance between cost and performance, ideal for mid to high end spring applications, passivation film formation through 18% chromium, resistance to atmospheric, fresh water and weak acidic and alkaline media (but chlorine containing environments need to be avoided), excellent elastic recovery after cold working, stable in use from -200°C to +300°C with short term peaks at 400°C.
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Description
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Through optimised composition control and processing, 304 stainless steel spring wire strikes a balance between cost and performance, ideal for mid to high end spring applications, passivation film formation through 18% chromium, resistance to atmospheric, fresh water and weak acidic and alkaline media (but chlorine containing environments need to be avoided), excellent elastic recovery after cold working, stable in use from -200°C to +300°C with short term peaks at 400°C. Weakly magnetic after solid solution treatment, may be slightly magnetic after cold working. Supports bright annealing (BA surface) or pickling (matte) to enhance aesthetics and corrosion resistance. For higher corrosion resistance or strength, customised 316, 301 and other material solutions are available.
Application Areas:
Automotive industry: clutch springs, suspension springs, seat belt retractors.
Medical equipment: surgical instrument springs, implant components.
Electronic appliances: connector contact springs, micro motor brushes.
Industrial machinery: valve springs, pressure sensor components.
Note : bundle, plastic bags, thin film, wooden pallet, standard seaworthy export packing or as customer demands
1.Mechanical properties
Condition
Tensile strength (MPa)
Elongation (%)
Hardness (HB)
Annealed
515
≥30
≤187
Cold drawn
1500
10-15
200-350
2.Physical properties
Condition
Density
Melting point
Thermal conductivity
Resistivity
Data
7.93 g/cm³
1400-1450°C
16.3 W/m-K
72 μΩ-m
Product Photos
FAQ
Q1: What is the main composition of 304 stainless steel spring wire?
A: The main components are chromium (Cr 18-20%), nickel (Ni 8-10.5%), carbon (C ≤ 0.08%), manganese (Mn ≤ 2.0%) and so on, in accordance with ASTM A240 standard.
Q2: What is the difference between 304 and 316 stainless steel spring wire?
A: 316 added molybdenum (Mo 2-3%), stronger resistance to chloride corrosion, suitable for marine environments; 304 lower cost, suitable for general corrosion environment.
Q3: Is 304 spring wire resistant to high temperature?
A: It can be used stably from -200℃ to +300℃ for a long time, and the short-term peak can reach 400℃, but the corrosion resistance may be reduced due to carbide precipitation at high temperature.
Q4: Why is 304 spring wire susceptible to rust in chlorinated environments?
A: Chlorine ions (e.g. seawater, salt spray) will destroy the surface passivation film, triggering pitting corrosion or stress corrosion cracking, and it is recommended to use 316 material instead.
Q5: How to choose between cold drawn and annealed condition?
Cold-drawn: High hardness (HB 200-350), low elongation (10-15%), suitable for highly elastic springs.
Annealed condition: low hardness (HB ≤187), high elongation (≥35%), suitable for subsequent forming or welding.
Q6: Do I need to anneal after cold drawing?
A: If it is necessary to eliminate processing stress or improve plasticity, it is recommended to carry out stress relief annealing at 260-315℃ for 1-2 hours to avoid the risk of brittleness.
Q7: Does it support welding? What are the precautions?
A: Welding is possible (TIG welding is preferred), but heat input should be controlled to avoid intergranular corrosion, and pickling or passivation is recommended after welding to restore corrosion resistance.
Q8: What industries commonly use 304 spring wire?
A: Automotive (suspension springs, seat belt retractors), medical (surgical instrument springs), electronics (connector contacts), industrial machinery (valve springs), and so on.
Q9: Can it be used in food contact scenarios?
A: It meets the food grade stainless steel standard (e.g. GB 4806.9), but we need to make sure the surface is clean and free of contamination, and we recommend choosing electrolytic polishing or BA surface.
Q10: What are the options for surface treatment?
Bright Annealed (BA): smooth and high corrosion resistance.
Pickling passivation: matte surface, removes oxide skin.
Electrolytic Polishing: Improve corrosion resistance and reduce surface adsorption.
Q11: How to prevent hydrogen embrittlement?
A: Dehydrogenation at 200°C for 4 hours is required after pickling or plating to avoid delayed fracture.
Q12: What is the common diameter range?
A: Standard diameters from 0.05mm (super fine wire) to 10mm, regular stock 0.1-6.0mm, support customised non-standard sizes.
Q13: What international standards are implemented?
ASTM A313 (American Standard)
JIS G4314 (Japanese Standard SUS304-WPB)
GB/T 4240 (Chinese national standard).
Q14: Is it environmentally friendly?
A: Comply with RoHS, REACH and other environmental certificates, some batches can provide material traceability report (e.g. melting furnace number).
Q15: How to test whether the quality is qualified?
A: Verified by chemical composition analysis (spectrometer), mechanical property test (tensile, hardness), and salt spray test (corrosion resistance).
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