310S Stainless Steel: Properties and Key Applications
แบ่งปัน
Table Of Content
Table Of Content
310S stainless steel is an austenitic stainless steel known for its excellent high-temperature strength and oxidation resistance. It is primarily composed of iron, chromium, and nickel, with a low carbon content that enhances its weldability and resistance to intergranular corrosion. The primary alloying elements include:
- Chromium (Cr): Typically 24-26%, which provides corrosion resistance and contributes to the steel's overall strength.
- Nickel (Ni): Usually 19-22%, which enhances toughness and ductility, especially at elevated temperatures.
- Molybdenum (Mo): Present in small amounts (up to 0.75%), which improves resistance to pitting and crevice corrosion.
Key Characteristics
310S stainless steel is characterized by its:
- High-temperature resistance: Suitable for applications involving temperatures up to 1150°C (2100°F).
- Corrosion resistance: Excellent resistance to oxidation and sulfidation.
- Good weldability: Low carbon content minimizes the risk of carbide precipitation during welding.
Advantages and Limitations
Advantages:
- Exceptional resistance to oxidation and corrosion at high temperatures.
- Good mechanical properties at elevated temperatures.
- Excellent weldability and formability.
Limitations:
- Higher cost compared to lower-grade stainless steels.
- Not suitable for applications involving strong reducing environments.
Historically, 310S has been widely used in industries such as petrochemical, power generation, and food processing due to its unique properties.
Alternative Names, Standards, and Equivalents
Standard Organization | Designation/Grade | Country/Region of Origin | Notes/Remarks |
---|---|---|---|
UNS | S31008 | USA | Closest equivalent to AISI 310 |
AISI/SAE | 310S | USA | Low carbon variant of 310 |
ASTM | A240 | USA | Standard specification for stainless steel plates |
EN | 1.4845 | Europe | Equivalent in European standards |
JIS | SUS310S | Japan | Japanese standard designation |
GB | 00Cr25Ni20 | China | Chinese equivalent with minor compositional differences |
The differences between these equivalents can affect performance in specific applications. For instance, while S31008 and SUS310S are similar, variations in nickel content can influence corrosion resistance in certain environments.
Key Properties
Chemical Composition
Element (Symbol and Name) | Percentage Range (%) |
---|---|
Fe (Iron) | Balance |
Cr (Chromium) | 24.0 - 26.0 |
Ni (Nickel) | 19.0 - 22.0 |
Mo (Molybdenum) | 0.0 - 0.75 |
C (Carbon) | ≤ 0.08 |
Mn (Manganese) | ≤ 2.0 |
Si (Silicon) | ≤ 1.0 |
P (Phosphorus) | ≤ 0.045 |
S (Sulfur) | ≤ 0.03 |
The primary role of chromium is to enhance corrosion resistance, while nickel improves toughness and ductility. Molybdenum contributes to pitting resistance, making 310S suitable for harsh environments.
Mechanical Properties
Property | Condition/Temper | Typical Value/Range (Metric) | Typical Value/Range (Imperial) | Reference Standard for Test Method |
---|---|---|---|---|
Tensile Strength | Annealed | 520 - 720 MPa | 75 - 104 ksi | ASTM E8 |
Yield Strength (0.2% offset) | Annealed | 205 - 310 MPa | 30 - 45 ksi | ASTM E8 |
Elongation | Annealed | 40 - 50% | 40 - 50% | ASTM E8 |
Hardness (Rockwell B) | Annealed | 70 - 90 HRB | 70 - 90 HRB | ASTM E18 |
Impact Strength | -20°C (-4°F) | 40 J | 30 ft-lbf | ASTM E23 |
The combination of high tensile and yield strength, along with good elongation, makes 310S suitable for applications requiring structural integrity under mechanical loading.
Physical Properties
Property | Condition/Temperature | Value (Metric) | Value (Imperial) |
---|---|---|---|
Density | Room Temperature | 7.93 g/cm³ | 0.286 lb/in³ |
Melting Point | - | 1400 - 1450 °C | 2550 - 2642 °F |
Thermal Conductivity | Room Temperature | 16.2 W/m·K | 112 BTU·in/h·ft²·°F |
Specific Heat Capacity | Room Temperature | 500 J/kg·K | 0.12 BTU/lb·°F |
Electrical Resistivity | Room Temperature | 0.72 µΩ·m | 0.72 µΩ·in |
The density and melting point indicate that 310S can withstand high temperatures, making it suitable for applications in extreme environments. Its thermal conductivity is moderate, which is beneficial for applications requiring heat retention.
Corrosion Resistance
Corrosive Agent | Concentration (%) | Temperature (°C/°F) | Resistance Rating | Notes |
---|---|---|---|---|
Chlorides | 0 - 10 | 20 - 60 | Good | Risk of pitting |
Sulfuric Acid | 0 - 10 | 20 - 50 | Fair | Susceptible to SCC |
Acetic Acid | 0 - 10 | 20 - 60 | Good | Moderate resistance |
Sea Water | - | 20 - 30 | Excellent | Resistant to corrosion |
310S stainless steel exhibits excellent resistance to oxidation and corrosion in various environments, including atmospheric, acidic, and saline conditions. However, it can be susceptible to stress corrosion cracking (SCC) in chloride environments.
When compared to grades like 316L, which contains molybdenum for enhanced pitting resistance, 310S may perform better in high-temperature applications but may not be as effective in chloride-rich environments.
Heat Resistance
Property/Limit | Temperature (°C) | Temperature (°F) | Remarks |
---|---|---|---|
Max Continuous Service Temp | 1150 °C | 2100 °F | Suitable for high-temperature applications |
Max Intermittent Service Temp | 1050 °C | 1922 °F | Short-term exposure only |
Scaling Temperature | 900 °C | 1652 °F | Risk of oxidation beyond this point |
310S maintains its strength and oxidation resistance at elevated temperatures, making it ideal for furnace components and heat exchangers. However, prolonged exposure beyond its maximum service temperature can lead to scaling and reduced mechanical properties.
Fabrication Properties
Weldability
Welding Process | Recommended Filler Metal (AWS Classification) | Typical Shielding Gas/Flux | Notes |
---|---|---|---|
TIG | ER310S | Argon | Excellent for thin sections |
MIG | ER310 | Argon + CO2 | Good for thicker sections |
SMAW | E310-16 | - | Suitable for all positions |
310S is highly weldable, with recommended filler metals that match its composition. Pre- and post-weld heat treatment can enhance the quality of welds and reduce the risk of cracking.
Machinability
Machining Parameter | 310S | AISI 1212 | Notes/Tips |
---|---|---|---|
Relative Machinability Index | 30% | 100% | Requires slower cutting speeds |
Typical Cutting Speed | 20 m/min | 60 m/min | Use carbide tools for best results |
Machining 310S can be challenging due to its toughness and work hardening characteristics. Optimal conditions include using sharp tools and slower cutting speeds to prevent excessive wear.
Formability
310S exhibits good formability, allowing for cold and hot working. However, its work hardening rate can lead to challenges in forming complex shapes. Recommended bend radii should be larger than those for lower grades to avoid cracking.
Heat Treatment
Treatment Process | Temperature Range (°C/°F) | Typical Soaking Time | Cooling Method | Primary Purpose / Expected Result |
---|---|---|---|---|
Annealing | 1050 - 1150 °C / 1922 - 2100 °F | 1 - 2 hours | Air or water | Relieve stresses, improve ductility |
Solution Treatment | 1000 - 1100 °C / 1832 - 2012 °F | 30 minutes | Water | Enhance corrosion resistance |
Heat treatment processes like annealing can significantly improve the ductility and toughness of 310S, making it more suitable for demanding applications.
Typical Applications and End Uses
Industry/Sector | Specific Application Example | Key Steel Properties Utilized in this Application | Reason for Selection (Brief) |
---|---|---|---|
Petrochemical | Heat exchangers | High-temperature strength, corrosion resistance | Essential for durability |
Power Generation | Boiler components | Oxidation resistance, mechanical strength | Critical for efficiency |
Food Processing | Ovens and furnaces | Cleanliness, high-temperature stability | Meets hygiene standards |
Aerospace | Exhaust systems | Lightweight, high strength | Reduces weight while maintaining performance |
310S is chosen for applications requiring high-temperature stability and resistance to corrosive environments, making it ideal for industries where reliability is paramount.
Important Considerations, Selection Criteria, and Further Insights
Feature/Property | 310S | 316L | 321 | Brief Pro/Con or Trade-off Note |
---|---|---|---|---|
Key Mechanical Property | High tensile strength | Good corrosion resistance | Excellent high-temp stability | 310S is stronger at high temps |
Key Corrosion Aspect | Good in high temps | Better in chloride environments | Good in high temps | 316L excels in saline conditions |
Weldability | Excellent | Good | Fair | 310S is easier to weld |
Machinability | Moderate | High | Low | 316L is easier to machine |
Approx. Relative Cost | Moderate | Higher | Moderate | Cost varies by market conditions |
Typical Availability | Common | Very common | Less common | 310S is widely available |
When selecting 310S, consider its high-temperature performance and corrosion resistance against the specific requirements of the application. While it may be more expensive than lower grades, its durability can lead to lower maintenance costs in the long run. Additionally, its availability in various forms (sheets, plates, pipes) makes it a versatile choice for many engineering applications.