316L — what the data actually supports

Data completeness: partial. Last verified 19 August 2026.

Designations

The “L” is the entire commercial reason 316L exists: carbon low enough that chromium carbide precipitation at grain boundaries during welding is suppressed, so the weld zone keeps its corrosion resistance. If a datasheet gives you 316 and 316L in one column, the mechanical minima are not the same.

Properties, with what each one rests on

8 sourced values, 1 gap named. Publishing the gaps is more useful than filling them from an aggregator that does not say where its numbers came from. The routes to filling them are the standard itself, a mill datasheet, or a mill certificate for your actual heat — which supersedes both at E5.

Where the numbers come from

Proof strength Rp0.2, minimum is E3, not E5. Claimed as a E5 value, but ASTM A240/A240M was not consulted directly. Under the demotion rule, a claimed level a reader cannot verify from the record alone drops one level. A second demotion to E0 was considered and rejected: two independent secondary sources give the same figure, so the value is sourced, not asserted. To restore it: open ASTM A240/A240M and record the edition, table and product form.

Proof strength Rp0.2, minimum (EN). 41% above the ASTM plate figure, and NOT directly comparable with it: different standard AND different product form. The product form was confirmed on 20 August 2026 by opening the Supra datasheet table directly — the row is C, cold rolled coil and sheet, under a heading reading “figures according to EN 10088-2 minimum values”. The Quarto plate row for the same grade is 220 MPa. Comparing 170 MPa of ASTM plate against 240 MPa of EN cold rolled sheet therefore mixes two variables, not one.

Elongation, minimum. This is A80, measured over an 80 mm gauge length. The A column, measured over 5.65√S0, is blank on the cold rolled row for this grade. On some grades the two differ by half — see 2101, where A is 30% and A80 is 20% on one row of one datasheet — so an elongation figure quoted without its gauge length cannot be compared with anything.

PREN. Corrected on 20 August 2026. The earlier note said the source stated neither its formula nor its composition; opening the datasheet showed that it states both — PRE = %Cr + 3.3 × %Mo + 16 × %N, and a typical composition of 17.2% Cr with 2.1% Mo, which reproduces the printed 24 exactly. It stays at E3 rather than rising, because the composition behind it is a typical value rather than a heat analysis, so the arithmetic is repeatable but the input is not traceable to any particular material. Below the threshold usually adopted for chloride service.

Why we do not just copy an aggregator. Because then this page would be a worse copy of MatWeb with no way for you to tell which rows to trust, and the one thing we have that MatWeb does not is the evidence column. Our coverage and its limits.

What 316L is usually chosen for

It is the default molybdenum-bearing austenitic, and the reasons are practical rather than exceptional. Single phase, so no phase balance to manage in welding. Forgiving heat input. Formable. Stocked by everyone in every product form. Every fabricator has qualified procedures for it. When a design is not strength-driven and the environment is not aggressive, 316L is chosen because choosing anything else has to be justified.

And what it is usually rejected for

Two things. Strength: at the 170 MPa ASTM A240 plate minimum it is weak for a structural section, and a strength-driven part in 316L is thick. Chlorides: the molybdenum helps against pitting relative to 304, but 316L is marginal in warm chloride service, and the failure mode that usually appears is crevice corrosion at gaskets and joints, which PREN does not predict.

The number to be more careful with than any of the above is the difference between a specified minimum and a typical value — a floor the standard guarantees, versus what a supplier’s production usually does. The full version, and the most expensive routine mistake in material data.

Compare

316L vs 2205 · 316L vs 316 · 316L vs 316ti · 316L vs 317l · 316L vs 904l · 316L vs 444

What this page does not cover

• Composition limits are not established, and they are what a purchase order actually specifies.
• Elevated and cryogenic temperature behaviour.
• Fatigue, fracture toughness and stress corrosion cracking.
• Welding procedure guidance, filler selection and post-weld treatment.
• Product forms other than plate, where minima differ.
• Whether 316L suits your application. No page can answer that.

Generated from data/materials/316l.yaml. Regenerate rather than editing this file by hand — edits here are lost on the next build.