Type 316/316L Stainless Steel is a molybdenum steel possessing improved resistance to pitting by solutions containing chlorides and other halides.
In addition, it provides excellent elevated temperature tensile, creep and stress-rupture strengths.
Chemcial Composition of 316/316L stainless steel tubing and pipe
| Grade | 316 | 316L |
|---|---|---|
| UNS Designation | S31600 | S31603 |
| Carbon (C) Max. | 0.08 | 0.030* |
| Manganese (Mn) Max. | 2 | 2 |
| Phosphorous (P) Max. | 0.045 | 0.045 |
| Sulphur (S) Max. | 0.03 | 0.03 |
| Silicon (Si) Max. | 1 | 1 |
| 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 |
| Nitrogen (N) | — | — |
| Iron (Fe) | Bal. | Bal. |
| Other Elements | — | — |
The main constituents of 316 stainless steel – other than iron – are Chromium and Nickel. However, it is the addition of 2% Molybdenum that provides the increased corrosion resistance.
316 contains 16 – 18% Chromium (Cr). Chromium is the essential chemical in all stainless steel and it is that which forms the thin passive layer that makes the metal “stainless”
316 also contains 10-14% Nickel (Ni). This is added to make the Austenitic structure more stable at normal temperatures.
The nickel also improves high-temperature oxidation resistance makes the steel resistant to stress corrosion cracking.
Where the steel is to be stretched formed a lower percentage (8%) of nickel should be selected. If the steel is to be deep drawn a higher percentage is better (9% or more).
In addition a number of other chemicals may be present but these are expressed as maximum permited levels with the exception of the increased quantity of carbon required in 316H – i.e. a minimum of .04% and a maximum of 0.10%
Electrical Properties
| Electrical Resistivity | 7.2e-005 ohm-cm | 7.2e-005 ohm-cm | at 20°C (68°F); 1.16E-04 at 650°C (1200°F) |
|---|---|---|---|
| Magnetic Permeability | 1.008 | 1.008 | at RT |
Typical Mechanical Properties- Stainless Steel 316/316L
| Material | Form | Tensile Strength (ksi) | Yield Strength (ksi) | % Elongation | Hardness HB |
|---|---|---|---|---|---|
| Alloy 316L | 316L Sheet AMS 5507 | 100 max | - | 45 | - |
| Alloy 316 | 316 Sheet AMS 5524 | 75 min | 30 | 45 | 207 max |
Physical Properties - 316/316L/316H stainless steel in the Annealed Condition at -20°F to +100°F
| Alloy | UNS Design | Spec. | Tensile Strength | Yield Strength | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| -ation | psi | MPa | ksi | psi | MPa | ksi | Elongation in 2 inches (min.) % | Grain Size Req. | Max. Hardness | Modulus of Elasticity (x106 psi) | Mean Coefficient of Thermal Expansion (IN./IN./°F x 10-6) | Thermal | ||
| 316 | S31600 | A249, A312 | 75000 | 515 | 75 | 30000 | 205 | 30 | 35 | — | 90 Rb | 28 | 9.2 | 116 |
| 316L | S31603 | A270, A312 | 70000 | 485 | 70 | 25000 | 170 | 25 | — | — | 90 Rb | 28 | 9.2 | 116 |
| 316H | S31609 | — | — | — | — | — | — | — | — | 7 or coarser | — | — | — | — |
Product Range - 316/316L Stainles steel
| Alloy | UNS Designation | Werkstoff NR. | Specifications* |
|---|---|---|---|
| 316 | S31600 | 1.4401 | A269, A/SA249, A/SA312, A1016, A632, A/SA688 |
| 316L** | S31603 | 1.4404 | A269, A/SA249, A/SA312, A1016, A632, A/SA688 |
Design Features – 316/316L Stainless Steel
- Type 316 is more resistant to atmospheric and other mild environments than Type 304. it is resistant to dilute solutions (i.e. 1-5%) of sulfuric acid up to 120°F. However, in certain oxidizing acids, Type 316 is less resistant than Type 304.
- 316 is susceptible to carbide precipitation when exposed in the temperature range of 800° – 1500°F and therefore is susceptible to intergranular corrosion in the as-welded condition. Annealing after welding will restore corrosion resistance.
- Type316L has the same composition as Type 316 except the carbon content is held below 0.03%. Not unexpectedly, its general corrosion resistance and other properties closely correspond to those of Type 316. However, it does provide immunity to intergranular attack in the as-welded condition or with short periods of exposure in the temperature range of 800° – 1500°F. The use of 316L is recommended when exposure in the carbide precipitation range is unavoidable and where annealing after welding is not practical. However, prolonged exposure in this range may embrittle the material and make it susceptible to intergranular attack.
- The maximum temperature for scaling resistance in contnuous services is about 1650°F, and 1500°F for intermittent service.
- May be susceptible to chloride stress corrosion cracking.
- Non-hardenable; non-magnetic in the annealed condition, and slightly magnetic when cold worked.
- Improved corrosion resistance to chlorides.
Typical Applications – Stainless Steel 316/316L
- Nuclear
- Chemical Processing
- Rubber
- Plastics
- Pulp & Paper
- Pharmaceutical
- Textile
- Heat exchangers, condensers & evaporators
Tensile Requirements – Stainless Steel 316/316L
Tensile Strength (KSI): 70
Yield Strength (KSI): 25
KSI can be converted to MPA (Megapascals) by multiplying by 6.895.
Stainless Steel Tube 316 Are Really Stainless?
Stainless steel tube has the ability to resist atmospheric oxidation, that is, stainless, it also has the ability to resist corrosion in the medium containing acid, alkali, salt corrosion – corrosion resistance.
But the capacity of its corrosion resistance changes with the chemical composition of the steel itself, using environmental conditions and type.
As 304 steel pipe (GB06Cr19Ni10, BSEN 1.4301), have absolute corrosion resistance good dry, clean atmosphere, but applied in coastal areas, containing a lot of salt mist from the sea, soon rust, but 316 steel tube (GB06Cr17Ni12Mo2; 1.4401) do well. So, not any type of stainless steel pipe are stainless and corrosion in any environment.
Technically, tube 316 should not rust. For highly oxidized acids (such as nitric acid), 316 stainless steel tubing is less corrosive.
The main show is:
1) Intergranular corrosion
Exposed to 427°C to 427°C temperature, 316 can cause chromium carbide in grain frontier precipitates, easy to produce intergranular corrosion in this harsh environment
2) Stress corrosion
In the halogenated environment, austenitic stainless steel is susceptible to corrosion by stress cracking. Although 316 has some of the best stress corrosion cracks, it is easier to be affected.
To protect 316 from oxidation, we suggest that:
1) The surface layer of impurities should be strongly ground, with a polishing/polishing wheel and paste, using a series of new polishing wheel covers and repeated washdowns, returning a high polish to the surface.
2) Light oils / wd40 etc will protect the overall surface
3) 304 grade stainless steel is recommended for indoor areas and 316 grade stainless steel or titanium pipe is recommended for coastal or other highly corrosive areas
Because 316 materials can resist corrosion in seawater.
4) Choose a reliable manufacturer, that the chemical composition conforms to national and international standards
317 vs 316 Stainless Steel – What’s the Difference
Would you like to know the difference between 317 stainless steel and 316 stainless steel? This article will discuss how these two alloys differ in their properties and uses. We will also explore why one might be chosen over the other for specific applications.
317 Stainless Steel Properties
317 stainless steel is an austenitic chromium-nickel alloy containing molybdenum. It has a higher corrosion resistance than 304 stainless steel, making it ideal for applications in harsh environments. In addition, it has excellent toughness and ductility properties, making it suitable for use in many applications that require high strength and durability. It has a higher nickel content than 316, which helps to increase its corrosion resistance.
316 Stainless Steel Properties
316 stainless steel is an austenitic chromium-nickel alloy containing molybdenum and increased levels of nickel compared to the 304 grade. It offers excellent corrosion resistance, particularly when exposed to saltwater or other corrosive liquids – making it ideal for marine or coastal applications. Additionally, its increased nickel content gives it superior formability compared to other alloys, allowing it to be used in complex shapes such as curves or angles with ease. It also has higher tensile strength than 304-grade stainless steel.
The primary difference between 317 and 316 is the amount of nickel content they have; 317 has more nickel than 316 does, which provides better corrosion resistance but makes the material more expensive too. Both grades are available in a variety of surface finishes, such as brushed, polished, or anodized, depending on your application requirements. In general, 317 is used for acidic environments, while 316 is most often used for marine applications or where there could be high levels of chlorides present in the environment due to its superior corrosion resistance against those elements.
Difference Between 317 and 316 Stainless Steel
Chemical Composition
The main difference between 317 and 316 stainless steel is the chemical composition. 317 stainless steel contains more molybdenum than 316 stainless steel. Molybdenum is a chemical element that increases the corrosion resistance of stainless steel.
Corrosion Resistance
Another difference between 317 and 316 stainless steel is the level of corrosion resistance. 317 stainless steel is more resistant to corrosion than 316 stainless steel. This is due to the higher molybdenum content in 317 stainless steel.
Strength
317 stainless steel is also stronger than 316 stainless steel. This is due to the higher molybdenum content in 317 stainless steel, which increases its strength.
Cost
The cost of 317 stainless steel is also higher than the cost of 316 stainless steel. This is due to the higher molybdenum content in 317 stainless steel, which makes it more expensive to produce.
Applications
317 stainless steel is typically used in high-temperature applications, such as furnaces, boilers, and heat exchangers. 316 stainless steel is typically used in food processing and medical equipment, as well as marine applications