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304 Stainless Steel
304 stainless steel, as a classic austenitic stainless steel, is ubiquitous in daily life due to its excellent corrosion resistance and mechanical properties. But when the ambient temperature rises, can it still perform well? This article will analyze the high-temperature performance limits and failure risks of 304 stainless steel to help you fully understand the performance of this material in long-term high-temperature environments.
How many degrees can 304 stainless steel withstand?
The heat resistance of 304 stainless steel can be defined from two dimensions: oxidation resistance and mechanical strength.
From the perspective of oxidation resistance, 304 stainless steel can withstand 870℃ under intermittent use conditions and 925℃ under continuous use conditions. Beyond this temperature, the material's antioxidant property will drop sharply, and the surface oxide film will lose its protective function -5. However, this is merely the limit that can be "endured", not the temperature for "long-term safe use".
From the perspective of maintaining mechanical properties, when the temperature exceeds 500℃, the high-temperature strength of the material begins to become a key consideration factor. Research shows that the high-temperature strength of 304 stainless steel significantly decreases with the increase of temperature within the range of 700-1400℃. Its zero strength temperature (ZST) is 1370℃, and its zero plasticity temperature (ZDT) is approximately 1350℃-3. This means that above 1350℃, the material basically loses its plasticity.
| Temperature range | Performance characteristics | Applicable suggestions |
| <500℃ | The strength remains good and the oxidation is slow | It can be used safely for a long time |
| 500-650℃ | The strength begins to decline, but the antioxidant property is still acceptable | Short-term use or non-load-bearing components |
| 650-800℃ | The sensitization phenomenon is significant, and the risk of intergranular corrosion increases | Not recommended for use in corrosive environments |
| 800-925℃ | The antioxidant limit and strength have been significantly reduced | Only applicable to intermittent working conditions |
| >925℃ | The oxide film fails and the material deteriorates rapidly | Prohibited use |
Three potential risks under long-term high temperatures
Placing 304 stainless steel in a long-term high-temperature environment is not merely a matter of "temperature tolerance", but rather involves facing multiple risks of failure.
High-temperature oxidation and shedding
When 304 stainless steel is used for a long time in an environment above 900℃, the oxide film on its surface will undergo a qualitative change. Research has found that in an O₂ atmosphere above 900℃, the oxide film of 304 stainless steel will show a phenomenon of entire layer peeling off, losing its protective function and causing the substrate to continuously repeat the process of oxidation, peeling and re-oxidation. In contrast, the 430 material, which is also a type of stainless steel, has better adhesion of the oxide film at the same temperature.
Intergranular corrosion risk - "sensitization" phenomenon
When 304 stainless steel is kept in the temperature range of 450 to 850℃ for a long time, it will undergo a "sensitization" phenomenon. The mechanism is that the carbon and chromium elements in the material combine at the grain boundaries to form chromium carbide precipitation, resulting in chromium-poor areas near the grain boundaries. When the chromium content in the chromium-poor zone is lower than the critical value required for passivation, selective corrosion along the grain boundaries will occur in the material in the corrosive medium.
Accelerated corrosion in molten salt environments
In some special high-temperature scenarios, such as molten salt heat transfer energy storage systems, the corrosion resistance of 304 stainless steel will drop sharply as the temperature rises. Experimental data show that in nitric acid molten salt at 565℃, the corrosion rate of 304 stainless steel is as high as 99.6×10⁻⁵ mg·cm⁻²·h⁻¹, and a loose oxide layer mainly composed of Fe₂O₃ and (Fe, Cr)₃O₄ is formed on the surface.
| Comparison of the corrosion performance of 304 stainless steel in molten salt at different temperatures | ||
|
Temperature |
Corrosion products |
Degree of corrosion |
|
400℃ |
Very few oxidation products |
Slight |
|
450-500℃ |
A small amount of Fe₂O₃ |
Medium |
|
565℃ |
Fe₂O₃ and (Fe, Cr)₃O₄ |
Severe, the corrosion rate increases significantly |
Conclusion
Therefore, can 304 stainless steel be used in long-term high temperature environments? The answer is: It is possible under certain conditions, but the temperature boundaries and working condition restrictions must be strictly adhered to.
If you have a new project that requires 304 stainless steel, AOXING can provide you with a comprehensive procurement plan and suggestions.
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Post time: Mar-20-2026
