ASTM A182 F316L Forgings

What is ASTM A182 F316L?

A182 F316L is 316L stainless steel written into a forging specification. ASTM A182 sets what the forge shop has to deliver: the analysis, the heat-treated condition, the mechanical acceptance, the testing and the marking. A drawing that calls for F316L rather than 316L is asking for a forged or rolled product certified to that specification, not only for a material with 316L chemistry.

Two limits define the grade. The first is carbon at 0.030 % maximum. Standard F316 allows 0.08 %, which is enough for chromium carbides to precipitate at grain boundaries while a weld cools through roughly 450 to 850 C, leaving those boundaries short of chromium and open to intergranular attack. The lower carbon starves that reaction, which is why F316L goes into welded assemblies that cannot be solution annealed again afterwards. The second is molybdenum at 2.00 to 3.00 %, the addition that separates the 316 family from 304 and holds the passive film together against chloride pitting and crevice attack.

Low carbon costs strength. F316L carries lower tensile and yield minima than F316, and the gap follows through into the code allowable stresses, which is why some designers move to F316LN instead and buy the strength back with nitrogen while keeping the carbon down.

A182 F316L chemical composition

The nickel range is worth a second look. F316L is specified 10.0 to 15.0 % Ni, wider at the top than the 10.0 to 14.0 % allowed for F316, because extra nickel helps hold austenite stable at the lower carbon level. Figures above are ladle analysis to ASTM A182. Product analysis on a finished forging may deviate within the tolerances of the standard. Every heat ships with its own certificate of analysis.

PREN of F316L

Pitting resistance equivalent number, taken as %Cr + 3.3 x %Mo + 16 x %N, puts a typical F316L heat in the mid-20s. That sits above 304L, which has no molybdenum at all, and below the 6 % molybdenum and duplex grades. Where the chloride level or the temperature runs past what the mid-20s will carry, the next steps are A182 F51, A182 F53 or A182 F44.

A182 F316L mechanical properties

These are acceptance minima, not typical test results. A solution-annealed F316L forging normally tests above them, but the contractual number is the minimum in the table and the actual figure printed on your EN 10204 certificate. If your calculation needs a guaranteed value higher than the ASTM minimum, put it on the enquiry so it goes onto the order rather than turning up as a problem at test.

ASTM A182 does not set a Brinell range for the austenitic grades the way it does for the low-alloy grades, so hardness is reported as measured rather than held to a band, unless your specification states one.

Physical properties are design-stage figures for a 316-type austenitic steel and are not acceptance criteria under ASTM A182. Where a code calculation depends on a physical property, take the value from the governing code.

A182 F316L heat treatment

What counts in the solution treatment is the cooling, not the soak. Carbides dissolve while the forging is at temperature, and the quench then has to move it through roughly 450 to 850 C fast enough that they have no chance to reform at the grain boundaries. On heavy sections that means a real water quench rather than still air, and the quench has to start without delay once the furnace door opens. A forging that spent too long in transfer can pass its tensile test and still fail an ASTM A262 intergranular corrosion test.

For the same reason there is no conventional stress-relief window for F316L of the kind a carbon steel has. Time spent in the sensitising range undoes the solution anneal. Where machining distortion is the worry, the machining sequence is the place to deal with it.

Forging A182 F316L

Austenitic stainless does not forge like carbon steel. It stays stiff at temperature, so the press works harder for the same reduction, and the working window at the low end is narrower. Finishing too cold leaves residual strain and risks cracking. Finishing too hot leaves a coarse grain that shows up later as poor ultrasonic response. Ring geometries are pierced and then rolled radially and axially, which runs the grain flow around the circumference instead of cutting across it. That is the main structural argument for a rolled ring over a ring cut out of plate.

What is A182 F316L equivalent to?

A cross-reference compares designation and analysis. Mechanical acceptance, permitted residuals, product-form scope and pressure-equipment approval all differ between ASTM and EN, and a 1.4404 certificate does not automatically satisfy a drawing calling for A182 F316L. Confirm any substitution with your design authority before ordering. Send us the two specifications and we will go through the differences with you.

F316L compared with F316, F316LN and F316N

Read the table from left to right and the trade-off is plain. Take F316 when you need the strength and the welding is controlled or the part can be re-annealed. Take F316L when the assembly is welded and cannot be re-annealed, or when the service is corrosive enough that sensitisation is the governing risk. Take F316LN when a code calculation fails on the low yield of F316L but you still need the low carbon. Many heats are dual-certified F316 and F316L, which is worth asking about if your drawing allows it.

F316L compared with F304L

The difference is molybdenum. Both are low-carbon austenitics with the same welding advantage, but F304L has none, so in chloride-bearing process streams, marine atmospheres or anything near seawater, F316L holds out at a higher threshold before it pits. In clean water, steam or food duty where chlorides are not the driver, F304L usually does the same job for less money.

Corrosion behaviour and where the grade stops

F316L handles general corrosion across a wide span of process chemistry, and the molybdenum makes it the default austenitic choice where chlorides are present but not severe. Its recognised strength is resistance to intergranular attack in the as-welded condition, which comes straight from the carbon limit.

The limits are just as much worth knowing. Chloride stress corrosion cracking is the classic failure mode for every standard austenitic, F316L included, and it becomes a live risk above roughly 60 C in chloride solutions under tensile stress no matter how respectable the PREN looks. Crevice geometry under gaskets and deposits will start attack at conditions the open surface tolerates. Strong reducing acids, hydrochloric in particular, are outside the range of the grade. If any of that describes your service, a duplex, super duplex or nickel alloy is the right answer, and we would rather say so at enquiry than ship you a forging that comes back.

A182 F316L forged products

Everything below is forged to your drawing or specification. F316L is not held as catalogue stock. Minimum order is one piece. Sizes beyond these ranges are often still possible, so send the drawing and we will confirm.

Size ranges describe the open-die and ring-rolling capability of the works across grades. What is achievable in F316L also depends on forging ratio, quench access for the section and the testing regime, all confirmed at drawing review.

Where A182 F316L is used

• Chemical and petrochemical plant: pressure vessel forgings, nozzles, heat exchanger components, piping flanges and fittings.
• Valves: bodies, bonnets, seat rings, stems and plugs for ball, gate, globe, check and plug valves in corrosive duty.
• Oil and gas, offshore and subsea: flanges, hubs, connectors and manifold parts where chloride exposure rules out plain 304L.
• Pulp and paper: digester and liquor tank components, paper machine parts.
• Food, beverage and pharmaceutical: process equipment and storage where cleanability and welded fabrication matter.
• Heat exchangers: tube sheets, baffle rings, shell flanges, channel covers.
• Water treatment and desalination: pump and valve forgings in treated and brackish water.
• General engineering: shafts, spindles, sleeves, gear blanks and rings where corrosion resistance outweighs the need for high strength.

Whether the grade suits a particular pressure code, ASME, PED or GB 150, depends on the approvals held for the grade and for the manufacturer rather than on the analysis alone. Tell us which code you build to and we will confirm what we can supply against it.

Testing, inspection and certification

Magnetic particle examination does not work on solution-annealed F316L, which is effectively non-magnetic. Where a drawing carries MPI on a stainless forging out of habit, liquid penetrant is the correct substitute, and we raise it at drawing review rather than as a deviation after the parts are made.

How an A182 F316L forging is made

1. Drawing review and quotationForgeability, ruling section, machining allowance, quench access and testing regime are checked before pricing, and anything likely to cause trouble at the press is raised then.
2. Steel making and material certificationMelt sourced to the required analysis with the mill certificate traceable to heat number. Electric arc furnace with AOD or VOD refining is the normal route for this grade, with ESR where a specification calls for it.
3. Heating and open-die forgingBillet soaked to 1150 to 1200 C, then upset and drawn under open dies to break down the cast structure, with reheats as needed to stay above the finishing temperature.
4. Ring rollingFor ring geometries the pierced blank is rolled radially and axially to final proportions on the ring mill.
5. Solution treatment and quenchReheat to 1040 C minimum, soak, then quench rapidly through the sensitising range.
6. Pickling and passivationScale removed and the passive film restored, where the order calls for it.
7. Testing and inspectionChemistry, mechanical testing, hardness, dimensional check, plus ultrasonic, penetrant, A262 or PMI where specified.
8. MachiningRough or finish machining to drawing, so the part arrives ready for your process rather than your lathe.
9. Documentation and despatchCertificates issued against the heat, parts marked to the ASTM A182 marking requirements, packed and shipped.

About the factory

Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. We forge carbon steel, alloy steel, tool steel, stainless steel and nickel alloys to customer drawing, and produce seamless rolled rings, forged flanges, bars, discs, shafts and hollow forgings across more than 300 grades. Jiangyin sits in the Yangtze River Delta within road distance of Shanghai and Ningbo, which is what makes export shipping of heavy single pieces workable.

Related grades

• A182 F316 forgings, the standard-carbon version with higher strength minima.
• A182 F321 forgings, titanium-stabilised, the other route to weld-zone corrosion resistance.
• A182 F51 duplex forgings, roughly double the yield strength with better chloride cracking resistance.
• A182 F53 super duplex forgings, for seawater and aggressive chloride service.
• A182 F55 super duplex forgings, the other super duplex common on subsea drawings.
• A182 F44 forgings, 6 % molybdenum austenitic, when F316L pits but you want to stay austenitic.
• 904L forgings, high-alloy austenitic for sulphuric and phosphoric acid duty.
• Incoloy 825 forgings, when the service runs past what any stainless will carry.
• All stainless steel forging grades.

Technical data on this page is compiled from the published requirements of ASTM A182 for Grade F316L and is given for guidance. It is not a warranty of properties. The certificate issued with each forging governs. Last reviewed 29 September 2026. A plain-text version of this datasheet is available at A182-F316L.md.