Comparison information between stainless steel 316L and 316H Steel
Comparison information between stainless steel 316L and 316H Steel
316L (low-carbon) stainless steel is preferred for its weldability and corrosion resistance at lower temperatures (due to less carbide precipitation), while 316H (high-carbon) stainless steel, due to its higher carbon content, offers greater strength and creep resistance at high temperatures (e.g., in furnaces), but at the expense of some resistance to welding sensitization. The key difference between the two lies in their carbon content (316L < 0.03%, 316H 0.04-0.10%), which determines their ideal applications, ranging from welded storage tanks (316L) to high-temperature structural components (316H).
What are the disadvantages of 316 stainless steel?
The main disadvantages of 316 stainless steel include its higher cost (due to the presence of molybdenum and nickel), difficulty in processing and forming (high hardness, prone to work hardening and wear), and potential problems during welding (intergranular corrosion and weld seam corrosion), requiring special techniques to maintain its corrosion resistance. Furthermore, it has low thermal conductivity, and can still corrode if improperly processed in extreme chloride/high-temperature environments.
Stainless Steel 316L is a low-carbon version of 316 stainless steel (carbon content ≤0.03%). Its core advantage lies in significantly improved resistance to chloride corrosion (especially pitting and crevice corrosion) through the addition of molybdenum (Mo), while its low carbon content provides excellent resistance to intergranular corrosion, making it particularly suitable for welding. It is widely used in chemical, marine, medical equipment, food industry, and architectural exterior applications where high corrosion resistance and weldability are required. It is a preferred grade among general-purpose stainless steels due to its superior corrosion resistance and higher welding reliability.
Stainless Steel 316H is a high-carbon version of 316 stainless steel (carbon content 0.04-0.10%). Its core characteristic is that the higher carbon content provides greater strength and creep resistance at high temperatures (approximately 480-900°C), while maintaining the good chloride corrosion resistance and oxidation resistance of the 316 series. It is specifically designed for high-temperature pressure equipment, such as boilers, superheaters, high-temperature heat exchangers, and petrochemical cracking units, where structural stability needs to be maintained for extended periods at high temperatures. However, it should be noted that the intergranular corrosion resistance in the sensitized zone may decrease after welding.
Chemical composition of Stainless Steel 316L and Stainless Steel 316H
| Element | 316L Stainless Steel (UNS S31603) | 316H Stainless Steel (UNS S31609) |
|---|---|---|
| Chromium (Cr) | 16.0 – 18.0 % | 16.0 – 18.0 % |
| Nickel (Ni) | 10.0 – 14.0 % | 10.0 – 14.0 % |
| Molybdenum (Mo) | 2.0 – 3.0 % | 2.0 – 3.0 % |
| Carbon (C) | ≤ 0.03 % | 0.04 – 0.10 % |
| Manganese (Mn) | ≤ 2.0 % | ≤ 2.0 % |
| Silicon (Si) | ≤ 1.0 % | ≤ 1.0 % |
| Phosphorus (P) | ≤ 0.045 % | ≤ 0.045 % |
| Sulfur (S) | ≤ 0.030 % | ≤ 0.030 % |
| Iron (Fe) | Balance | Balance |
| Nitrogen (N) | ≤ 0.10 % | ≤ 0.10 % |
Strength and Durability
316H offers higher strength at elevated temperatures, making it ideal for high-pressure and high-temperature applications.
316L has slightly lower strength but exhibits excellent resistance to intergranular corrosion.
316 strikes a balance between strength and corrosion resistance, suitable for general applications.
Corrosion Resistance
All three grades offer excellent corrosion resistance, especially in marine environments.
Due to its resistance to sensitization, 316L is preferred in highly corrosive environments.
316H is better suited for high-temperature environments requiring corrosion resistance.
Applications
Due to its high-temperature strength, 316H is used in chemical processing, boilers, and heat exchangers.
316L is commonly used in pharmaceutical, food processing, and marine applications where welding is critical.
316 is widely used in construction, piping, and general engineering applications.
Summary and comparison
| Feature | 316L Stainless Steel | 316H Stainless Steel |
|---|---|---|
| Carbon (C) | Low (≤ 0.03%) | High (0.04–0.10%) |
| Primary Benefit | Excellent weldability, corrosion resistance after welding | Enhanced strength at high temperatures |
| Best Application | Welded components, marine | Boilers, heat exchangers, high‑temperature pipes |
| Temperature Suitability | Good for general use, resists sensitization | Ideal for applications > 500°C (932°F) |
