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AISI 316 vs 316L Stainless Steel – What’s the Difference

AISI 316 vs 316L Stainless Steel

If you’re in the stainless steel market, you’ve probably come across two different types—AISI 316 and AISI 316L. What’s the difference between these two types of Steel? Let’s look at their strengths, weaknesses, and applications so that you can make an informed decision when choosing the right type of stainless Steel for your needs.

Difference Between AISI 316 and 316L Steel

The main difference between AISI 316 and AISI 316L is that AISI 316 contains 2-3% molybdenum, while AISI 316L does not contain any molybdenum. Molybdenum is a chemical element used to increase corrosion resistance in steel alloys. As such, molybdenum can make the Steel more robust and resistant to corrosive agents such as chlorine or salt water. Another difference is that AISI 316L contains lower levels of carbon than its counterpart—generally 0.03% or less compared to 0.08% in standard-grade stainless Steel. This makes it easier to weld and less prone to cracking due to stress concentrations caused by welding heat-affected zones (HAZ).

What is Their Strength?

Both types of stainless Steel are strong and highly durable, but each has unique strengths. For example, AISI 316 is known for its excellent resistance to corrosion from salt water and other harsh environments. It is ideal for marine applications or those exposed to saltwater spray or splashes. It also resists pitting caused by exposure to chloride ions, making it highly suitable for applications involving food processing machinery or medical equipment that come into contact with human sweat or saliva regularly. On the other hand, since it lacks molybdenum, AISI316L is less resistant than its counterpart. Still, it offers good corrosion resistance in milder environments such as freshwater bodies or low-chloride soils. It also provides superior weldability due to its lower carbon content which reduces HAZ cracking during welding operations performed on parts of this material type.

Chemical Composition

The chemical composition is the main difference between AISI 316 and 316L Stainless Steel. AISI 316L contains a lower carbon content than AISI 316. As a result, AISI 316L has a higher corrosion resistance than AISI 316. Additionally, the weldability of AISI 316L is better than that of AISI 316.

Mechanical Properties

The mechanical properties of AISI316 and AISI316L are very similar. However, the lower carbon content of AISI316L gives it a slightly higher yield strength and tensile strength than AISI316. The lower carbon content makes AISI316L less sensitive to welding sensitization, which can lead to intergranular corrosion.

Corrosion Resistance

AISI316 and AISI316L both have excellent corrosion resistance in a variety of environments. However, the lower carbon content of AISI316L gives it slightly higher resistance to sensitization during welding, which can lead to intergranular corrosion. The lower carbon content makes AISI316L less susceptible to pitting and crevice corrosion in chloride-containing environments.

Weldability

The weldability of both AISI316 and AISO16l is excellent. However, the lower carbon content of AO16l makes it slightly easier to weld than AI56. The lower carbon content also makes Ao16l less sensitive to welding sensitization, which can lead to intergranular corrosion.

Applications

AO56 is commonly used in food processing equipment, chemical processing equipment, medical devices, and marine applications due to its excellent corrosion resistance and weldability. Ao16l is often used in construction due to its high strength and low susceptibility to intergranular corrosion.

Conclusions:

When deciding between AISI316 and AISI316L stainless steels for your project, several factors should be considered, including cost, application environment (i.e., exposure time/conditions), desired strength/resistance level(s), ease of fabrication/welding/joining operations required etc. Both types offer excellent corrosion resistance, but if maximum strength against chloride ion attack is desired, then go with the former; however, if superior weldability is more critical, then opt for the latter instead since it will have better results in this regard due to its lower carbon content. No matter your choice, there’s no wrong decision here, so pick what best suits your needs!

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