Differences between 316 and 316L stainless steel

A. Richard,

316L has lower carbon allowed. It will be less susceptible to sensitization, a condition caused when carbon combines with chromium around the grain boundaries, thereby depleting the grain boundary areas of chromium. That would make the grain boundary areas less corrosion resistant. Sensitization occurs with heating into the 800 °F to 1300 °F region, so it's a welding or annealing problem.

The 316L will also be softer than straight 316, again due to the lower carbon.

Good luck!

A. The difference between 316 and 316L is the amount of carbon that is in the material.

316 has .08 Max carbon content while 316L has a .03 Max carbon content.

I am not aware that there is a significant difference in the corrosion resistance of one over the other. The primary reason for using an L grade of stainless steel is that this will reduce the tendency of the material to crack after welding.

If you use a stainless steel with a high carbon content the welds may crack spontaneously as they cool down from the welding. This type of cracking is known as "hot brittleness".

In short, if the item you are fabricating will be welded then use an L grade material. If it is not then it does not matter.

I hope this helps you.

A. 316 and 316L differ only by the amount on carbon in them. As I understand it, 316 L has lower carbon such that when welded the chromium carbide that forms does not deplete the chromium to the point where the corrosion of the stainless is deleteriously impacted. This effect, known as chromium depletion, shows itself in most plating shops where 316 welded tanks are used. The welded corners typically rust whereas the bulk of the exposed stainless is untouched. 316 has a carbon content of 0.08% Max whereas 316L is 0.03% Max.

A. The main difference is the lower carbon content, 316 being 0.030, 316L being as low as 0.016. Other elements are also somewhat lower,such as sulfur, phosphorus and copper. The 316L is more ductile when annealed, and is markedly more corrosion resistant, especially after welding. 316L is much more weld friendly than 316, as it is less susceptible to intergranular corrosion, after welding or air service up to 1600 °F (intermittent) 1700 °F (continuous), due to carbide precipitation. In 316 carbide precipitation will occur between 900 F-1070 F after 9 hours, whereas 316L will precipitate carbides between 900 °F - 1010 °F after 181 hours, 316L showing much more resistance to sensitization.

A. The Temperatures at which the precipitation of Chromium carbides is present is between 1004-1553 °F.

Source: ASM Materials Engineering Dictionary [on Amazon affil links]

A. www.sandmeyersteel.com/images/316-316L-317L-Spec-Sheet.pdf
Hope it helps

A. Hi Shanmugam. Welding is not my area of expertise, but I'd say "yes" because suppliers these days often give you 316L when you buy 316 anyway because it's easier for them to manufacture, stock, and sell just the single product now that the cost differential has declined.

Regards,

A. Hi Sidhik.

The cost differential has decreased to the point where some suppliers offer just the single 316L product anyway. I am not aware of a marking system, but it really shouldn't matter for bolts, nuts, & washers anyway because (as I understand it and per the earlier remarks on this page) the value of the 316L product only comes into play when it is subjected to welding temperatures.

Regards,

A. 316L has less carbon than 316, and therefore is more corrosion resistant. Otherwise, the composition is the same.

Lyle Kirman

A. Hi Bill-

No, there's no difference in ductility or formability due solely to the carbon content difference of 316 and 316L. Now, you might see a difference in a specific group of two samples, if they've been given different levels of cold rolling or working. I've seen 'annealed' 300 series stainless steels with tensile strengths between 70 ksi and 120 ksi, just due to the processing done by different mills at different times. That can make a difference in your formability.

Good luck!

A. Hi Shaji. 316 is slightly easier to make and more widely specified, and therefore is sometimes slightly less expensive.

But there seems to be no particular downside to substituting 316L for 316, so I am seeing a trend where steel warehouses seem to be stocking only 316L in some shapes, in which case you get the same thing at the same price whichever you specify.

Regards,

A. Hi Nasari. To my knowledge the corrosion situation would be no worse than a 316 pipe welded to a 316 fitting.

Regards,

A. One way is to have the stainless steel analysed for carbon.

Hi Doods. Milt has told us that "316 has a carbon content of 0.08% Max whereas 316L is 0.03% Max."
So the difference is that 316L has lower carbon content, and it's probably best to say the "L" stands for 'low carbon'.

Regards,

A. Dattatraya,
316 and 316L are nearly identical. It's not about which material you have, but how clean that surface is.

A. Hi Isack. The first possibility is that the components (for example corrugated sheet roofing and hollow tubing columns) may simply be unavailable in SS316L. Other possible problems include difficulty in fabricating: SS3xx work hardens, so they may not be able to cut it and drill it with the tools they customarily use. If welding is required, their welders may not be experienced with this material.

As a course of action I suggest you do some internet research into what shapes are available and unavailable so there is a workable design, and then consider trying to retain a construction contractor experienced in working with this material rather than general roofing contractors. Good luck.

Regards,