stainless steel 316/316L vs 316L
A frequently asked question to our employees is the following:
Can you offer your fittings in 316L stainless steel?
The answer is in most cases: Yes, we could also offer you the 316L stainless steel product. The manufacture of these special products requires appropriate planning and procurement in addition to the actual series production. This generally results in much longer delivery times than when using our standard 316/316L stainless steel.
Due to the production of small batch sizes, the prices for the specials are also usually higher than for the standards. Also minimum order quantities and proportionate set-up costs for the production can arise, which makes the use of these screw connections unattractive for you.
For these reasons, we always recommend that you orient yourself towards stainless steel 316/316L.
Not only these facts speak for the use of stainless steel 316/316L but also technical reasons. We will take a closer look at these in the following.
Chemical composition of stainless steel 316 and 316/316L
| Ni | Cr | C | ||
| 316L | ASTM A479/A182 |
10 bis 14% | 16 bis 18% | 0,030 % |
| 316/316L | ASTM A479/A182 |
10 bis 14% | 16 bis 18% | 316 = 0,08 % 316L = 0,030% |
| 316/316L | Swagelok | Min. 12% | Min. 17% | 0,040% |
| Austenitic structure more stable at 12% Ni. This ensures better deformable, embrittlement-resistant alloys. | Higher corrosion resistance as required at the lower limit 16% according to ASTM |
What can be concluded from the data in the table?
- 316/316L stainless steel is also called dual certified stainless steel because it complies with 316 and 316L stainless steel standards. We can also prove this fact with the 3.1 certificate according to EN 10204.
- The 316L stainless steel has a slightly lower carbon content than the 316L stainless steel. The 316/316L stainless steel we use is close to the carbon content of the 316L stainless steel.
- The stainless steel used by Swagelok provides the better quality required by the ASTM lower limit due to the higher alloy content of chromium and nickel.
So for good reason we can recommend the dual certified 316/316L stainless steel instead of 316L stainless steel for most fittings. Exceptions are welding fittings, which are still made of 316L stainless steel.
Not all articles are yet available with dual certified material. Please do not hesitate to contact us.