SUS316 Stainless Steel Standard Guide
SUS316 is an austenitic stainless steel widely used in medical, food, and chemical industries due to its excellent corrosion resistance.
Its key advantage over SUS304 is the addition of molybdenum (Mo), which significantly improves resistance to chloride-induced corrosion.
ASTM Standard & Composition
SUS316 is commonly specified under ASTM A240 standard.
Typical composition:
- Cr: 16–18%
- Ni: 10–14%
- Mo: 2–3%
- C: ≤0.08%
The addition of molybdenum is the key factor distinguishing 316 from 304, granting it superior resistance to pitting corrosion.
Analysis of Corrosion Resistance Mechanisms
The corrosion resistance of SUS316 stems primarily from three factors:
- Chromium forms a dense oxide film (Cr₂O₃)
- Molybdenum enhances resistance to pitting corrosion
- Low carbon content reduces the risk of intergranular corrosion
In environments containing chloride ions (such as seawater or cleaning agents), molybdenum effectively retards the propagation of localized corrosion.
Material Selection Guidelines for SUS316
In practical engineering applications, the selection of SUS316 should focus on the following factors:
Application Suitability
Medical industry: Biocompatibility and cleanliness
Food industry: Resistance to corrosion from cleaning agents
Chemical industry: Resistance to acids, alkalis, and chloride environments
Machinability
SUS316 possesses good ductility but is prone to work hardening during machining; therefore, cutting tools and parameters require optimization.
In industrial manufacturing, digital machining platforms (such as precision stainless steel parts machining services) can be utilized for rapid design validation.
Conclusion
SUS316 remains a reliable stainless steel grade for corrosive environments. Compliance with ASTM A240 ensures consistent performance in engineering applications.