304 Spring Wire - Maximum Service Temperature Explained

Product Introduction

TOPONE supplies 304 stainless steel spring wire in 0.15-12 mm diameters for springs and wire forms that also have to survive heat. 304 is often specified by habit for hot service, but its temperature ceiling is real and worth understanding before the spring is designed. This page states the practical limits and the alternatives when 304 runs out of margin.

Product Specifications

Two Different Limits: Oxidation and Strength

304 can resist oxidation in air up to roughly 750-800 degrees C depending on cycle frequency. Above that, the oxide scale thickens and spalls. But a spring has a second, much lower limit: creep and stress relaxation. Cold-drawn 304 loses a large share of its spring force over time at 300-400 degrees C already, which is why hot springs usually move to higher-carbon or more stable grades rather than running 304 to its oxidation limit.

What Happens as Temperature Rises

• Above about 300 degrees C: measurable stress relaxation begins in loaded springs.
• Above about 550 degrees C: sensitization risk after long exposure; corrosion resistance near welds drops.
• Above about 750 degrees C: continuous oxidation scaling; intermittent cycles to 800 degrees C are tolerated.
• Above 800 degrees C: 309, 310 or nickel alloys take over.

Choosing the Grade for Heat

• Up to 300 degrees C with static loads: 304 spring wire is generally suitable.
• 300-550 degrees C, loaded springs: consider 302 type with higher carbon, or specify stress-relieved springs and verify relaxation.
• 550-800 degrees C, mostly static or lightly loaded: 309/310 wire for oxidation resistance.
• Chlorides present with the heat: 316 family, with the same temperature logic.

Applications

• Oven, furnace and heater component springs
• Exhaust and engine peripheral wire forms
• Heat-treatment fixtures and mesh belts
• Bolted assemblies with high-temperature spring elements

Product Advantages

• Honest temperature guidance with the order, not just a datasheet
• Certified chemistry per heat for predictable high-temperature behaviour
• Drawn tempers that balance hot strength and relaxation resistance
• 0.15-12 mm range with bright, soap coated or pickled surface

Quality Control

Chemistry and mechanical values are reported on the 3.1 MTC for every coil lot. For high-temperature projects we can supply grade alternatives and stress-relief recommendations matched to your working temperature.

Selection and Ordering Notes

1. State the maximum and continuous service temperature.
2. Describe the load: static, cycling, or loaded continuously at temperature.
3. Mention the atmosphere (air, exhaust gas, chlorides).
4. Ask about alternative grades if the duty exceeds 304's limits.
5. Confirm diameter, temper, surface and packaging.