What are the mechanical properties of A182 F6NM?

ASTM A182/A182M requires for F6NM a minimum tensile strength of 115 ksi or 790 MPa, a minimum 0.2 percent yield strength of 90 ksi or 620 MPa, minimum elongation of 15 percent, minimum reduction of area of 45 percent and maximum hardness of 295 HBW. Under NACE MR0175 and ISO 15156-3 hardness is capped at 23 HRC, so NACE material is normally limited to about 75 ksi yield, or up to about 85 ksi with controlled cast chemistry and tempering.

What is the chemical composition of F6NM?

ASTM A182 F6NM, UNS S41500, contains carbon 0.05 percent maximum, manganese 0.50 to 1.00 percent, phosphorus 0.030 percent maximum, sulfur 0.030 percent maximum, silicon 0.60 percent maximum, chromium 11.5 to 14.0 percent, nickel 3.5 to 5.5 percent and molybdenum 0.50 to 1.00 percent, balance iron.

What is equivalent to A182 F6NM?

A182 F6NM corresponds to UNS S41500, EN 1.4313 which is X3CrNiMo13-4, AISI 415 and, in bar form, ASTM A276 grade S41500. The matching cast grade is CA6NM.

How is F6NM heat treated?

F6NM is quenched and tempered. Hardening is carried out above about 1010 degrees Celsius, or 1850 degrees Fahrenheit, with cooling in air or oil, followed by tempering at roughly 560 to 605 degrees Celsius for the standard ASTM condition. NACE MR0175 and ISO 15156-3 call for a double temper after quenching, a first temper of about 650 to 690 degrees Celsius and a second temper of about 595 to 620 degrees Celsius, to hold hardness at or below 23 HRC. The grade is air hardening, so heavy sections carry little risk of quench cracking.

Is A182 F6NM approved for sour service?

UNS S41500 and F6NM are listed in NACE MR0175 and ISO 15156-3 for sour service provided hardness does not exceed 23 HRC and the heat treatment restrictions are met. The NACE requirement has to be stated on the order so that tempering and hardness testing are controlled to suit.

What corrosion resistance does F6NM have?

F6NM has a PREN of about 15 and performs well in moderately corrosive media free of chlorides. It does not replace duplex or super duplex grades in chloride bearing service. Surface finish has a large effect, a polished surface resisting corrosion far better than a rough machined or as forged surface.

Who manufactures A182 F6NM forgings?

Jiangyin Jiangnan Metal Co., Ltd., an open die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, produces ASTM A182 F6NM forged rings, seamless rolled rings, flanges, round bars, shafts, sleeves, bushings, discs and tube sheets to customer drawings. Telephone plus 86 189 2135 9659, email sales at steelforgepieces.com.

ASTM A182 F6NM Forgings, UNS S41500 / EN 1.4313 (X3CrNiMo13-4)

Q: What is ASTM A182 F6NM?

ASTM A182 F6NM is a forging grade of low carbon martensitic stainless steel with about 13 percent chromium, 4 percent nickel and 0.5 to 1.0 percent molybdenum, designated UNS S41500. The nickel and molybdenum additions give sub zero notch ductility better than the standard 13Cr grades 410 and 420 Mod, together with good weldability. It is used for forged valve bodies, seats and gates, flanges, pump and compressor parts, hydro turbine components and oil and gas forgings.

13Cr-4Ni-Mo martensitic stainless steel forged rings, seamless rolled rings, flanges, round bars, shafts, sleeves, bushings, discs and tube sheets, open-die forged to drawing by Jiangyin Jiangnan Metal Co., Ltd.

F6NM key data

Grade and UNS: ASTM A182 F6NM, UNS S41500
Equivalents: EN 1.4313 (X3CrNiMo13-4), AISI 415, cast grade CA6NM
Type: Low carbon 13 % Cr, 4 % Ni, Mo martensitic stainless steel, air hardening
Tensile strength: 115 ksi [790 MPa] min
Yield strength, 0.2 %: 90 ksi [620 MPa] min
Hardness: 295 HBW max to ASTM; 23 HRC max for NACE MR0175 sour service
PREN: about 15, for moderately corrosive chloride-free media
Service temperature: -60 °C to 350 °C (-76 °F to 660 °F)
Melting route: EAF + LF + VOD, ESR on request
Certification: EN 10204 3.1, or 3.2 with third-party witness

What ASTM A182 F6NM is

ASTM A182 F6NM, UNS S41500, is a forging grade of low carbon martensitic stainless steel with nominally 13 % chromium, 4 % nickel and 0.5 to 1.0 % molybdenum. The nickel and molybdenum additions give sub zero notch ductility better than that of the standard 13Cr grades 410 and 420 Mod, and the grade also welds well and resists corrosion in moderately aggressive service. F6NM is air hardening, so heavy forged sections can be hardened with little danger of cracking during heat treatment.

The grade is the forged counterpart of the cast grade CA6NM, and the same UNS S41500 composition is covered in bar form by ASTM A276. F6NM is accepted for sour service under NACE MR0175 / ISO 15156-3 when the 23 HRC hardness limit and the related tempering restrictions are satisfied.

Chemical composition, A182 F6NM / UNS S41500

Composition limits in percent by mass, ASTM A182/A182M grade F6NM
Limit	C	Si	Mn	P	S	Cr	Ni	Mo	Fe
Min	-	-	0.50	-	-	11.50	3.50	0.50	Balance
Max	0.05	0.60	1.00	0.030	0.030	14.00	5.50	1.00	Balance

Mill datasheets for the equivalent grade 1.4313 sometimes quote a narrower chromium band of 12.0 to 14.0 %. Tighter internal ranges can be agreed at order stage.

Mechanical properties, A182 F6NM

Tensile and hardness requirements, ASTM A182/A182M grade F6NM, quenched and tempered
Property	Requirement
Tensile strength, min	115 ksi [790 MPa]
Yield strength, 0.2 % offset, min	90 ksi [620 MPa]
Elongation in 2 in. [50 mm] or 4D, min	15 %
Reduction of area, min	45 %
Hardness	295 HBW max
Hardness, NACE MR0175 / ISO 15156-3	23 HRC max

Buyers ordering for sour service should note that the 23 HRC cap limits the strength that can be developed. NACE grade F6NM is commonly restricted to about 75 ksi minimum yield; with targeted cast chemistry and close control of tempering, about 85 ksi yield can be reached while still meeting the hardness limit. Please state on the enquiry whether the acceptance criteria are the ASTM condition or the NACE condition, since the two are not the same.

Charpy V-notch testing, for example at -40 °C (-40 °F), is available as a supplementary requirement. Acceptance values are set by the project specification and reported on the test certificate.

Heat treatment of F6NM forgings

Quench and temper practice for F6NM / 1.4313
Condition	Hardening	Tempering	Cooling
Standard ASTM, condition T	1010 °C min (1850 °F min)	about 560 to 605 °C (1040 to 1120 °F)	Air or oil from hardening, air after temper
NACE MR0175 / ISO 15156-3	1010 °C min (1850 °F min)	Double temper, first about 650 to 690 °C, second about 595 to 620 °C	Air or oil from hardening, air after each temper

The second temper required for sour service tempers the fresh martensite formed on cooling from the first temper, and that is what brings hardness reliably below 23 HRC. Cycles are set according to section thickness and are documented by furnace charts issued with the forgings.

Equivalent grades and designations

F6NM cross reference
System	Designation
ASTM, forgings	A182 F6NM
ASTM, bar	A276 and A479 grade S41500
UNS	S41500
EN and DIN	1.4313, X3CrNiMo13-4, also written X2CrNiMo13-4
AISI	415
Cast grade	CA6NM
Sour service listing	NACE MR0175 / ISO 15156-3, 23 HRC max

Orders are accepted against any of these designations to the same drawing: X3CrNiMo13-4, UNS S41500, 1.4313 and Alloy 6NM.

Corrosion resistance and limits of use

At a PREN of about 15, F6NM gives useful service in moderately corrosive media that are free of chlorides. Surface condition matters a great deal, and the same alloy performs better polished than with a rough as-machined or as-forged surface. Where chlorides, seawater or strong acids are involved, a duplex or super duplex grade such as A182 F51, F53 or F55, or a nickel alloy such as Inconel 625, is the better choice. Those grades can be quoted against the same drawing for comparison.

Where F6NM forgings are used

Valve parts: bodies, bonnets, seats and seat rings, gates, wedges, stems and valve blocks for ball, gate, globe, check and plug valves.
Pressure parts: flanges, tube sheets, nozzles, forged pipe and tube sections, fittings.
Rotating equipment: pump and compressor components, shafts, spindles, impeller hubs, sleeves, bushings, discs and gear blanks.
Hydropower: turbine runner components and the related forged rings and shafts, as the wrought counterpart of CA6NM castings.
Oil, gas and petrochemical: tubulars, wellhead and subsea components, and sour service parts held to 23 HRC max.
Highly loaded parts needing low temperature toughness down to -60 °C, including locking and safety bolting.
Tooling and mould blocks where an air hardening corrosion resistant martensitic grade is preferred.

F6NM product forms

Open-die forged shapes in A182 F6NM, made to customer drawing or specification
Group	Items
Rings	Forged rings, seamless rolled rings, ring blanks, gear rings, retaining rings
Solid round	Round bars, shafts, eccentric shafts, spindles, stepped shafts, billets
Flat and disc	Discs, disks, blind blanks, tube sheets, plates, blocks
Hollow	Sleeves, bushings, hollow bars, forged tube and pipe, cylinders
Machined	Rough machined and finish machined forgings, valve parts, nozzles, manifolds

Please state required dimensions and single piece weight in the enquiry so that feasibility can be confirmed against press and ring mill capacity.

Melting, testing and certificates

F6NM is melted by EAF plus LF plus VOD, with ESR available where cleanliness or homogeneity requirements call for it. Forgings are ultrasonically examined to EN 10228-3, SEP 1921 or ASTM A388 as specified, and supplied with inspection documents to EN 10204 3.1, or EN 10204 3.2 witnessed by a third party such as TUV, SGS, BV, LR or DNV. Options on request include PMI, liquid penetrant and magnetic particle examination, hardness survey for NACE compliance, low temperature Charpy testing, grain size determination, intergranular corrosion testing and full traceability by heat number.

Questions on A182 F6NM

How does F6NM differ from 410 stainless steel?

Both are 13 % chromium martensitic stainless steels. F6NM is the low carbon version, 0.05 % C max, with 3.5 to 5.5 % nickel and 0.5 to 1.0 % molybdenum added. Those additions give clearly better sub zero notch ductility and weldability than 410 and 420 Mod, along with somewhat better corrosion resistance, which is why F6NM is specified for valve and pressure containing forgings.

Is F6NM the same as CA6NM?

The chemistry is essentially the same 13Cr-4Ni-Mo. F6NM is the forged grade under ASTM A182, UNS S41500, while CA6NM is the cast grade. Forged F6NM has a worked grain structure and is specified where casting discontinuities are not acceptable.

Can F6NM be welded?

Yes, and weldability is one reason the grade is chosen. Welding is normally carried out in the solution annealed or tempered condition with suitable preheat, followed by post weld tempering. For sour service the post weld heat treatment has to keep both base metal and weld within 23 HRC, and procedure qualification including weld hardness testing is required under NACE MR0175 / ISO 15156.

Which certificates come with the forgings?

EN 10204 3.1 as standard, or EN 10204 3.2 with third-party endorsement on request, covering heat chemistry, mechanical test results, heat treatment records, NDT reports and dimensional inspection, traceable to the heat number.

What is needed for a quotation?

Drawing or dimensions, for rings the OD by ID by height and for bars the diameter by length, plus quantity, delivery condition, ASTM condition T or NACE double tempered, any supplementary testing, certificate type and destination port. Send it to sales@steelforgepieces.com.

A182 F6NM quotation

Jiangyin Jiangnan Metal Co., Ltd., open-die forging factory

Address: No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Tel: 0086-189-2135-9659
Email: sales@steelforgepieces.com

Prices for F6NM forgings are quoted per drawing, piece weight and heat treatment condition, so there is no list price. Send the drawing or the size required, whether forged rings, seamless rolled rings, flanges, shafts, bars, sleeves, bushings, discs or tube sheets, and a price will be quoted with the certification you need.

Send the F6NM enquiry

Technical data on this page follows ASTM A182/A182M and NACE MR0175 / ISO 15156-3 for grade F6NM, UNS S41500, together with mill datasheets for the equivalent grade EN 1.4313. Figures are for guidance and the governing documents are the applicable edition of the standard and the agreed order specification. Last updated 30 September 2026.