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

Q: What is 1.4313 steel?

1.4313 is the EN material number for X3CrNiMo13-4, a low-carbon soft-martensitic stainless steel containing about 13 % chromium, 4 % nickel and 0.5 % molybdenum, with carbon held to 0.05 % maximum. Because the carbon is low and the nickel high, it hardens in air to a tough martensite rather than a brittle one, so it combines the strength of a martensitic stainless steel with impact toughness down to −60 °C and good weldability. It is standardised in EN 10088-3, EN 10250-4 and EN 10222-5, and the same steel appears in ASTM A182 as Grade F6NM (UNS S41500). Jiangyin Jiangnan Metal Co., Ltd. forges it into rings, flanges, shafts, bars, discs and valve components at its works in Jiangyin, Jiangsu Province, China.

Q: Is 1.4313 the same as F6NM and UNS S41500?

They are the same family of steel under three naming systems: 1.4313 / X3CrNiMo13-4 is the European designation in EN 10088-3, ASTM A182 F6NM is the American forging grade and UNS S41500 is its unified number. The chemistry windows are close but not identical, so they are not automatically interchangeable on a certificate. EN 10088-3 sets Cr 12.0–14.0 %, Ni 3.5–4.5 %, Mo 0.30–0.70 % and requires nitrogen at 0.020 % minimum; ASTM A182 F6NM allows Cr 11.50–14.00 %, Ni 3.50–5.50 % and Mo 0.50–1.00 % with no nitrogen minimum. State the governing specification on the enquiry and the melt can be aimed to satisfy both at once where the order needs dual certification.

Q: What are the mechanical properties of 1.4313 in the quenched and tempered condition?

EN 10088-3 defines three quenched and tempered conditions up to 160 mm thickness. +QT700: Rp0.2 ≥ 520 MPa, Rm 700–850 MPa, A ≥ 15 %, KV ≥ 70 J. +QT780: ≥ 620 MPa, 780–980 MPa, ≥ 15 %, ≥ 70 J. +QT900: ≥ 800 MPa, 900–1100 MPa, ≥ 12 %, ≥ 50 J. Between 160 mm and 250 mm, acceptance moves to transverse test pieces at reduced levels: 12 % and 50 J for +QT700 and +QT780, and 10 % and 40 J for +QT900. Annealed (+A) material is limited to 1100 MPa tensile and 320 HBW. ASTM A182 F6NM instead calls for 620 MPa (90 ksi) yield minimum, 790 MPa (115 ksi) tensile minimum, 15 % elongation, 45 % reduction of area and 295 HBW maximum.

Q: Can 1.4313 forgings be supplied for NACE MR0175 sour service?

Yes. NACE MR0175 / ISO 15156-3 accepts wrought UNS S41500, the F6NM version of this steel, for sour service provided hardness does not exceed 23 HRC. Meeting that limit means a deliberate heat-treatment route rather than a single temper: austenitise at about 950–1050 °C, cool in air or oil, then double temper, first at roughly 650–690 °C and again at roughly 595–620 °C, so reverted austenite is stabilised and virgin martensite is not re-formed on cooling. The practical trade-off is strength, because holding hardness below 23 HRC generally caps yield strength well below the 800 MPa available in +QT900. Each sour-service order is supplied with hardness records and a manufacturer's compliance statement referencing the grade, the heat-treatment condition and the measured hardness.

Q: What sizes of 1.4313 forgings can you make?

Seamless rings roll to 6,000 mm outside diameter on a 6 m radial-axial mill, with 3 m and 1 m mills for smaller sizes and an upset-and-punch route from OD 50 mm. The heaviest single forging is 30 tonnes, worked on 6,300 t, 4,000 t and 2,000 t hydraulic presses. Downstream limits are set by the shop: heat-treatment furnaces take work to 8,000 × 2,000 × 2,000 mm, two 15 m well-type furnaces allow long shafts to be quenched vertically, vertical lathes machine to Ø5,000 mm swing, horizontal lathes to 14,000 mm between centres, and the CNC deep-hole drilling machine bores Ø1,600 × 10,000 mm.

Q: What is 1.4313 used for?

1.4313 is the standard steel for hydro-electric turbine runners, blades and shafts, where cavitation resistance, toughness and weld repairability matter more than maximum strength. It is also used for pump and compressor casings, shafts and impellers; valve bodies, bonnets, stems and seat rings; wellhead and Christmas tree components in sour service; steam and gas turbine parts; pressure-vessel flanges and tube sheets; and tooling and dies for pressure die casting. Its working window in the quenched and tempered condition runs from −60 °C to about +300 °C.

Q: Is 1.4313 weldable?

Yes, and good weldability is the main reason the low-carbon 13Cr-4Ni grades displaced older 13 % Cr steels such as 1.4021 and 1.4057 in turbine and valve work. All arc processes can be used. Preheat of roughly 100–200 °C is usual, heavier sections benefiting from the upper end; shielding gases containing hydrogen or carbon should be avoided; and a matching filler or an E410NiMo-type consumable is normal. After welding the joint is tempered, or annealed and re-heat-treated, to restore toughness in the heat-affected zone. For sour service the HAZ hardness must also be held within the 23 HRC base-metal limit, which in practice means a qualified post-weld heat treatment.

Q: What is the minimum order quantity and lead time for 1.4313 forgings?

The minimum order is 10 kg, with no minimum piece count, so a single small ring or one test bar is quotable as well as a one-off heavy forging. Normal lead time is 20 to 60 days from order confirmation. Standard 1.4313 melted through the electric arc furnace with ladle refining and vacuum oxygen decarburisation sits at the lower end; orders needing electroslag or vacuum arc remelting, third-party witnessed inspection to EN 10204 3.2, or corrosion testing placed with an outside laboratory sit at the upper end. Quotations are normally returned within two working days of receiving a drawing or specification.

Q: Who supplies 1.4313 / X3CrNiMo13-4 forgings from China?

Jiangyin Jiangnan Metal Co., Ltd. is an integrated melting works and open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, operating since 1997 with 460 staff. Unlike a forging shop that buys billet, it melts its own steel, so a 1.4313 forging is traceable from the melt number rather than from a purchased billet certificate. The works holds CCS, BV, DNV, LR and NK approvals, issues EN 10204 3.1 certificates as standard and 3.2 witnessed certificates on request, and exports to North America, Europe, the Middle East and Asia-Pacific. Enquiries: sales@steelforgepieces.com, +86 189 2135 9659.

Summary

1.4313 (X3CrNiMo13-4) is a low-carbon soft-martensitic stainless steel with about 13 % chromium, 4 % nickel and 0.5 % molybdenum, standardised in EN 10088-3 and supplied in the USA as ASTM A182 Grade F6NM, UNS S41500. Low carbon and high nickel make it air-hardening and tough rather than brittle, so it keeps ISO-V impact energy of 70 J down to −60 °C while reaching 900–1100 MPa tensile strength in the +QT900 condition, and it is accepted for sour service under NACE MR0175 / ISO 15156 at 23 HRC maximum.

Jiangyin Jiangnan Metal Co., Ltd., an integrated melting works and open-die forging factory in Jiangyin, Jiangsu Province, China operating since 1997, melts, forges, heat-treats, machines and tests 1.4313 on one site. Rings roll to 6,000 mm outside diameter, single pieces run to 30 tonnes, the minimum order is 10 kg, and every part is traceable from its melt number.

EN designation: 1.4313 · X3CrNiMo13-4
US designation: ASTM A182 F6NMUNS S41500 · AISI 415
Type: Soft-martensitic stainless13Cr–4Ni–Mo, air-hardening
Delivery conditions: +A · +QT700 · +QT780 · +QT900
Service range (Q&T): −60 °C to +300 °C
Sour service: NACE MR0175 / ISO 1515623 HRC max, double tempered
Max ring OD: 6,000 mm6 m radial-axial ring mill
Max single piece: 30,000 kg6,300 t press · 60 t heat
Minimum order: 10 kgno minimum piece count
Lead time: 20–60 days
Certification: EN 10204 3.1 / 3.2CCS · BV · DNV · LR · NK
Melt route: EAF + LF + VODESR / VAR where specified

Values below are quoted from the standards named in each table caption. Figures marked typ. are indicative literature values, not specification minima, and should be confirmed against the governing standard before being used in design.

1. What 1.4313 is, and why it exists

Ordinary 13 % chromium martensitic stainless steels such as 1.4021 (X20Cr13) and 1.4057 (X17CrNi16-2) get their strength from carbon. That works, but it leaves them notch-sensitive, awkward to weld and poor at low temperature. 1.4313 takes the opposite route: carbon is capped at 0.05 % and nickel is raised to 3.5–4.5 %, with 0.30–0.70 % molybdenum added for pitting resistance.

The result is a steel that still transforms to martensite on cooling in air, so heavy sections harden through without a drastic quench, but to a soft, low-carbon martensite carrying finely dispersed reverted austenite after tempering. That microstructure is what gives 1.4313 its combination of high proof strength, 70 J of ISO-V impact energy at sub-zero temperature and weldability good enough for field repair of turbine runners.

Because molybdenum is present, its corrosion resistance is comparable to 1.4057 and clearly better than plain 13 % Cr steel in mildly aggressive, chloride-free media. It is not a substitute for duplex or austenitic grades in chloride or strongly oxidising service. For those, see A182 F51 (duplex), A182 F55 (super duplex) or 904L.

2. Designations and equivalent grades

Cross-reference for 1.4313 / X3CrNiMo13-4. Equivalences are nearest-grade guidance; chemistry windows differ between systems.
System / standard	Designation	Note
EN 10088-3 / EN 10088-1	X3CrNiMo13-4 · 1.4313	Bars, rods, sections, semi-finished
EN 10250-4	X3CrNiMo13-4	Open-die forgings, general engineering
EN 10222-5	X3CrNiMo13-4	Forgings for pressure purposes
EN 10272 / EN 10028-7	X3CrNiMo13-4	Bars / flat products for pressure purposes
ASTM / ASME	A182 F6NM · A240 / A479 UNS S41500	Forgings, plate, bar
UNS	S41500	S42400 is a related higher-Mo wrought grade
AISI (informal)	415 · 418	Not a formal AISI type
GB/T (China)	04Cr13Ni5Mo · S41595	Old designation 0Cr13Ni5Mo
JIS (Japan)	SUS F6NM	SCS5 / SCS6 are the cast equivalents
AFNOR (France)	Z6CND13-04 · Z6CN13-04	—
BS (UK, withdrawn)	425C11	—
DIN 17440 (withdrawn)	X4CrNi13-4 · G-X5CrNi13-4	Superseded by EN 10088
Cast counterpart	CA6NM · UNS J91540 · 1.4317 (GX4CrNi13-4)	Casting, not a forging substitute

We also quote the same steel under its other names. Search our index for A182 F6NM, X3CrNiMo13-4, UNS S41500 or 13Cr-4Ni.

3. Chemical composition

Chemical composition, % by mass, single values are maxima. EN column: EN 10088-3:2023 (identical to the 2014 edition) for X3CrNiMo13-4 / 1.4313. ASTM column: ASTM A182/A182M Grade F6NM.
Element	EN 10088-3 — 1.4313	ASTM A182 — F6NM
C (carbon)	≤ 0.05	≤ 0.05
Si (silicon)	≤ 0.70	≤ 0.60
Mn (manganese)	≤ 1.50	0.50 – 1.00
P (phosphorus)	≤ 0.040	≤ 0.030
S (sulphur)	≤ 0.015	≤ 0.030
Cr (chromium)	12.0 – 14.0	11.50 – 14.00
Ni (nickel)	3.5 – 4.5	3.50 – 5.50
Mo (molybdenum)	0.30 – 0.70	0.50 – 1.00
N (nitrogen)	≥ 0.020	not specified
Fe (iron)	balance	balance

Dual certification. The two windows overlap but do not coincide. EN requires a nitrogen minimum and a tighter sulphur limit; ASTM allows more nickel and molybdenum and less chromium. An order that must satisfy both is aimed at the intersection (Cr 12.0–14.0 %, Ni 3.5–4.5 %, Mo 0.50–0.70 %, S ≤ 0.015 %, N ≥ 0.020 %) at the furnace. Because the steel is melted here rather than bought in as billet, that is settled at the furnace rather than by sorting.

4. Mechanical properties by delivery condition

Room-temperature mechanical properties, EN 10088-3:2023, X3CrNiMo13-4 / 1.4313. Test-piece orientation is given with the thickness. Hardness values are for guidance only; for rods, only the tensile strength values apply.
Condition	Thickness t / dia. d	HBW max	R_p0.2 min MPa	R_m MPa	A min %	KV min J
+A (annealed)	any	320	—	≤ 1100	—	—
+QT700	≤ 160 (long.)	—	520	700 – 850	15	70
+QT700	160 < t ≤ 250 (transv.)	—	520	700 – 850	12	50
+QT780	≤ 160 (long.)	—	620	780 – 980	15	70
+QT780	160 < t ≤ 250 (transv.)	—	620	780 – 980	12	50
+QT900	≤ 160 (long.)	—	800	900 – 1100	12	50
+QT900	160 < t ≤ 250 (transv.)	—	800	900 – 1100	10	40

Room-temperature mechanical requirements, ASTM A182/A182M Grade F6NM (UNS S41500), quenched and tempered.
Property	Requirement (metric)	Requirement (imperial)
Tensile strength, R_m	≥ 790 MPa	≥ 115 ksi
Yield strength, 0.2 % offset	≥ 620 MPa	≥ 90 ksi
Elongation in 2 in. / 50 mm	≥ 15 %	≥ 15 %
Reduction of area	≥ 45 %	≥ 45 %
Hardness	≤ 295 HBW	≤ 295 HBW
Hardness, NACE MR0175 sour service	≤ 23 HRC	≤ 23 HRC

Reading the two tables together. ASTM F6NM sits between EN +QT780 and +QT900: its 620 MPa yield floor matches +QT780, while its 790 MPa tensile floor lies inside the +QT780 band. The 23 HRC sour-service ceiling is the binding constraint in oilfield work and normally holds delivered yield strength below what +QT900 would give, so strength and sour-service hardness cannot both be maximised. Note also that EN 10088-3:2005, now superseded, listed +QT700 as 700–800 MPa and contained a well-known typographical error in the +QT780 tensile band; the values above follow the 2014 and 2023 editions. Some mill datasheets additionally offer a +QT650 condition (R_p0.2 ≥ 520 MPa, R_m 650–830 MPa, A ≥ 15 %, KV ≥ 70 J) drawn from related EN parts rather than EN 10088-3; we will supply to it if your specification calls for it.

5. Physical properties

Physical properties of 1.4313 / X3CrNiMo13-4 at 20 °C unless stated. Literature values, indicative.
Property	Value
Density	7.70 g/cm³ (7,700 kg/m³)
Thermal conductivity, 20 °C	25 W/(m·K)
Specific heat capacity, 20 °C	430 J/(kg·K)
Electrical resistivity, 20 °C	0.60 Ω·mm²/m
Mean coefficient of thermal expansion, 20–100 °C	10.5 × 10⁻⁶ K⁻¹
Modulus of elasticity, 20 °C	≈ 200 GPa typ.
Magnetisable	Yes — ferromagnetic
Useful service range, quenched and tempered	−60 °C to approx. +300 °C

Elevated-temperature proof strength values and the design modulus are tabulated in EN 10088-1 and EN 10088-3; ask us for the relevant extract if you need them for a code calculation.

6. Heat treatment

Heat-treatment practice for 1.4313 / X3CrNiMo13-4 / F6NM. Soak times depend on section; final cycles are set per order and recorded on a furnace chart.
Operation	Temperature	Cooling / notes
Forging / hot working	approx. 1150 °C down to 850 °C	Air cool after forging; heavy sections cooled under control to avoid cracking
Annealing (+A)	600 – 650 °C	Furnace or slow air cool. Do not exceed 825 °C during annealing. Result: R_m ≤ 1100 MPa, ≤ 320 HBW
Austenitising / hardening	950 – 1050 °C	Air, oil or polymer quench. The grade is air-hardening, so heavy sections harden through
Temper → +QT700 / +QT650	650 – 700 °C, optionally + 600 – 620 °C	Air cool. Lowest strength, highest toughness
Temper → +QT780	550 – 600 °C	Air cool
Temper → +QT900	520 – 580 °C	Air cool. Highest strength condition
ASTM A182 Condition T temper	560 – 605 °C (1040 – 1120 °F)	Air cool, after hardening from ≥ 1010 °C (1850 °F)
NACE MR0175 double temper	1st: 650 – 690 °C · 2nd: 595 – 620 °C	Air cool after each. Required route to bring hardness to ≤ 23 HRC

The reason sour-service orders need two tempers rather than one is metallurgical. Tempering in the 620–640 °C region reverts some martensite to austenite; nickel and other gamma stabilisers diffuse into those islands and stabilise them. Temper too high and that reverted austenite loses stability, so it transforms back to fresh, untempered martensite on cooling, and hardness goes up rather than down. The second, lower temper conditions any such martensite and brings the measured hardness reliably under 23 HRC.

7. Sour service — NACE MR0175 / ISO 15156

NACE MR0175 / ISO 15156-3 lists the low-carbon martensitic stainless steels (wrought UNS S41500 and S42400, and cast J91540 (CA6NM)) as acceptable for H₂S-containing production environments provided hardness does not exceed 23 HRC. The limit applies to base metal, weld metal and heat-affected zone alike.

On an order this has four consequences.

Heat treatment is prescribed

Quench from 950–1050 °C, then double temper (≈ 650–690 °C followed by ≈ 595–620 °C). A single high temper will not reliably deliver ≤ 23 HRC.

Strength is capped in practice

Holding hardness under 23 HRC generally keeps delivered yield strength well below the 800 MPa of +QT900. Design to the hardness limit first.

Welds need qualification

HAZ and weld-metal hardness must also stay within the base-metal limit, tested per ISO 6507-1 (HV 10 / HV 5) or ISO 6508-1 (Rockwell 15N) as MR0175 directs.

Documentation travels with the part

Each sour-service order ships with hardness records and a manufacturer's compliance statement naming the grade, the heat-treatment condition and the measured hardness.

Thickness or diameter outside the scope of MR0175, or a combination of partial pressure, chloride and pH that sits near an annex boundary, should be raised at enquiry stage so the route is agreed before the steel is melted.

8. Welding, machining and surface

Welding

Good weldability is the main reason the 13Cr-4Ni grades displaced older 13 % Cr martensitic steels in turbine and valve work, and it is why hydro runners in 1.4313 can be weld-repaired in place. All arc processes apply. Preheat of roughly 100–200 °C is usual, with the upper end for sections over about 10 mm; shielding gases containing hydrogen or carbon should be avoided; a matching filler or an E410NiMo-type consumable is normal. After welding, temper, or anneal and re-heat-treat, to restore heat-affected-zone toughness. For sour service the post-weld cycle must be qualified against the 23 HRC limit.

Machining

Machinability tracks hardness and is best in the annealed or lower-strength tempered conditions. The work-hardening rate is higher than plain 13 % Cr steel, so the grade behaves closer to an austenitic stainless than to 1.4021: positive rake, rigid setups, generous feed and sharp tooling. We normally rough-machine after heat treatment and finish-machine last, which is also what makes reliable volumetric inspection possible.

Corrosion behaviour and surface finish

Corrosion resistance in the quenched and tempered condition is good in mildly aggressive, chloride-free media and comparable to 1.4057 thanks to the molybdenum. Surface condition has a large part in that resistance: a polished surface performs markedly better than an as-machined or rough one. The grade takes a high polish, which is part of why it suits turbine and pump hydraulic surfaces.

9. 1.4313 product forms we forge

Every item below is forged from a single piece of steel melted on site, with no welding, no casting and no purchased billet of unknown origin.

Seamless rolled rings

Ring-rolled from a punched preform on a radial-axial mill, rectangular or contoured section, to OD 6,000 mm.

Also: contoured rolled rings · gear ring blanks · slewing rings

Forged rings

Upset-and-punched rings for sections outside the ring-mill envelope and for heavy-reduction work, from OD 50 mm.

Also: retaining rings · valve seat rings

Forged flanges

Weld neck, blind, slip-on, socket weld, lap joint, orifice, long weld neck and girth flanges to ASME B16.5, B16.47 and API 6A.

Governing grade: ASTM A182 F6NM

Forged shafts

Turbine and pump shafts, stepped shafts, pinion and gear shafts, spindles and rotors, quenched vertically in a 15 m well furnace to control distortion.

Also: rolls · spindles

Forged bars & blocks

Round, flat, square and hex bars, die and mould blocks, the feedstock route for machined valve bodies and tooling.

Also: round bars · flat bars

Discs, tube sheets & covers

Solid forged discs, tube sheets, covers and hubs, supplied proof-machined for volumetric inspection.

Also: forged blanks · gear blanks

Valve & wellhead parts

Valve bodies, bonnets, stems, seat rings, blocks, spools, nozzles and manifolds for Christmas trees, wellheads, BOPs and risers.

API 6A · NACE MR0175 / ISO 15156

Cylinders, sleeves & bushings

Hollow forged cylinders, sleeves, bushings and heavy-wall pipe sections bored from solid forged blanks.

Also: forged pipe · couplings

10. Size envelope for 1.4313

Working envelope by product form, set by the plant's own equipment. Larger or longer parts may be possible in two pieces — ask.
Product	Limit	Set by
Seamless rolled rings	OD 50 – 6,000 mm	6 m radial-axial ring mill; upset-and-punch route below the mill range
Forged shafts	up to 14,000 mm turned length	Ø1,600 × 14,000 mm horizontal lathe; 15 m well furnace for vertical quench
Discs, tube sheets, blocks	up to Ø5,000 mm machined	Ø5,000 mm vertical turning lathe
Bored cylinders, hollow shafts	up to Ø1,600 × 10,000 mm	CNC deep-hole drilling machine
Heat-treated envelope	up to 8,000 × 2,000 × 2,000 mm	Car-bottom furnaces (14 furnaces in total)
Single-piece weight	up to 30,000 kg	60 t maximum heat size; 6,300 t / 4,000 t / 2,000 t presses
Minimum order	10 kg	Weight-based, no minimum piece count

11. Where 1.4313 is used

Hydro-electric power

Turbine runners, blades, Pelton buckets, guide vanes, shafts, wicket gates and pump-turbine components. The classic application: cavitation resistance, sub-zero toughness and field weld repairability.

Oil & gas, sour service

Valve bodies, bonnets, stems and seat rings; wellhead and Christmas tree parts, spools, nozzles and BOP components to API 6A and NACE MR0175 / ISO 15156.

Pumps & compressors

Casings, shafts, impeller and diffuser blanks, wear rings and balance drums for water, brine-free process and pipeline duty.

Steam & gas turbines

Rotor and casing components, blade rings, retaining rings and control-valve parts operating up to about 300 °C.

Pressure equipment

Flanges, tube sheets, covers and nozzles to EN 10222-5 and ASTM A182, for heat exchangers and pressure vessels.

Tooling & general engineering

Tools and dies for pressure die casting, plastics moulds requiring corrosion resistance, and shafting for marine and paper machinery.

12. Testing, inspection and certification

Because the steel is melted here, chemistry is verified at the furnace rather than taken from a supplier's certificate. Every forging is released against a documented route: melt analysis, mechanical testing on a representative test piece, non-destructive examination, dimensional inspection, then certification.

In-house testing applied to 1.4313 / F6NM forgings, and the standards it is performed to.
Discipline	Method / equipment	Standard
Chemical analysis	Optical emission spectrometry (SPECTROTEST TXC25); infrared C/S analyser	ASTM E415 · ASTM E1019
Alloy verification	Handheld PMI analyser	Positive material identification
Tensile	600 kN and 300 kN universal testing machines	ASTM A370 · ISO 6892
Impact	Pendulum impact tester with low-temperature bath, to −60 °C	ASTM A370 · ASTM E23 · ISO 148
Hardness	Portable Leeb hardness, converted; bench Brinell / Rockwell via accredited lab where specified	ASTM A956 · ASTM E140 · ASTM E10
Ultrasonic	Full-digital flaw detectors on proof-machined surfaces	ASTM A388 · EN 10228-3 · SEP 1921
Magnetic particle	Multipurpose MT crack detection	ASTM E709
Metallography	Microscope, mounting press, polisher; grain size and inclusion rating	ASTM E112 · ASTM E45
Certification	Mill test certificate as standard; witnessed certificate on request	EN 10204 3.1 / 3.2

Class approvals: CCS (China Classification Society), BV (Bureau Veritas), DNV, LR (Lloyd's Register) and NK (ClassNK). EN 10204 3.2 certificates witnessed by a classification society or by SGS, TÜV or your own inspector are available on request. Tests outside our in-house scope (intergranular corrosion to ASTM A262 or G28, pitting to ASTM G48, impact below −60 °C, bench hardness) are placed with an accredited third-party laboratory and reported alongside the mill certificate. Flag them at enquiry stage so they are scheduled before shipment rather than added afterwards.

13. Melted and forged in one works

Most forging suppliers in China buy billet. This works starts one step earlier, at the furnace, and that changes two things that matter commercially for a grade like 1.4313.

First, the chemistry can be aimed at the forging it will become rather than accepted as delivered. For 1.4313 that is not a small point: the nitrogen minimum, the tight sulphur ceiling and the nickel–molybdenum balance that decides whether 23 HRC is achievable are all set in the melt shop, not on the press. Carbon, alloy, stainless and duplex grades run through a 25 t electric arc furnace, 25 t and 50 t ladle furnaces and 30 t and 60 t vacuum oxygen decarburisation units, VOD being the route to low carbon with controlled nitrogen. Where a specification calls for a remelted grade, 3 t vacuum induction melting, 6 t vacuum arc remelting and 3 t and 6 t protective-atmosphere electroslag remelting are on site. Maximum heat size is 60 tonnes.

Second, traceability starts at the melt number instead of stopping at a purchased billet certificate. Steel moves through the presses, the ring mill, 14 heat-treatment furnaces and the machine shop without leaving the site, so the chain from heat to shipped part is unbroken, which is what a class surveyor or a sour-service audit asks to see.

14. Request a quotation for 1.4313 forgings

Send these six items and you will normally have a price within two working days

Grade and governing specification — e.g. 1.4313 to EN 10088-3, or ASTM A182 F6NM, or dual-certified
Dimensions, or a drawing — PDF, DWG, DXF or STEP; e.g. OD 1200 × ID 900 × H 260 mm
Quantity and expected repeat volume — e.g. 12 pcs, about 4 × per year
Delivery condition — as-forged with allowance, proof-machined, or finish-machined to drawing
Heat treatment and testing — e.g. +QT780, or quenched and double tempered to ≤ 23 HRC for NACE MR0175; UT to ASTM A388, impact at −60 °C
Certification and destination port — e.g. EN 10204 3.2 witnessed by DNV, Rotterdam

Minimum order 10 kg, no minimum piece count. Lead time 20–60 days. Customer audits, pre-shipment inspection and third-party witness testing are welcome. Please arrange visits by email in advance so an English-speaking engineer is available.

Email the RFQ Call +86 189 2135 9659 Contact page

Telephone, WhatsApp and WeChat: +86 189 2135 9659. Business hours Monday–Saturday, 08:00–17:30 China Standard Time (UTC+8).

15. Frequently asked questions about 1.4313

What is 1.4313 steel?

1.4313 is the EN material number for X3CrNiMo13-4, a low-carbon soft-martensitic stainless steel containing about 13 % chromium, 4 % nickel and 0.5 % molybdenum, with carbon held to 0.05 % maximum. Because the carbon is low and the nickel high, it hardens in air to a tough martensite rather than a brittle one, so it combines the strength of a martensitic stainless steel with impact toughness down to −60 °C and good weldability. It is standardised in EN 10088-3, EN 10250-4 and EN 10222-5, and the same steel appears in ASTM A182 as Grade F6NM (UNS S41500). Jiangyin Jiangnan Metal Co., Ltd. forges it into rings, flanges, shafts, bars, discs and valve components at its works in Jiangyin, Jiangsu Province, China.

Is 1.4313 the same as F6NM and UNS S41500?

They are the same family of steel under three naming systems: 1.4313 / X3CrNiMo13-4 is the European designation in EN 10088-3, ASTM A182 F6NM is the American forging grade and UNS S41500 is its unified number. The chemistry windows are close but not identical, so they are not automatically interchangeable on a certificate. EN 10088-3 sets Cr 12.0–14.0 %, Ni 3.5–4.5 %, Mo 0.30–0.70 % and requires nitrogen at 0.020 % minimum; ASTM A182 F6NM allows Cr 11.50–14.00 %, Ni 3.50–5.50 % and Mo 0.50–1.00 % with no nitrogen minimum. State the governing specification on the enquiry and the melt can be aimed to satisfy both at once where the order needs dual certification.

What are the mechanical properties of 1.4313 in the quenched and tempered condition?

EN 10088-3 defines three quenched and tempered conditions up to 160 mm thickness. +QT700: R_p0.2 ≥ 520 MPa, R_m 700–850 MPa, A ≥ 15 %, KV ≥ 70 J. +QT780: ≥ 620 MPa, 780–980 MPa, ≥ 15 %, ≥ 70 J. +QT900: ≥ 800 MPa, 900–1100 MPa, ≥ 12 %, ≥ 50 J. Between 160 mm and 250 mm, acceptance moves to transverse test pieces at reduced levels: 12 % and 50 J for +QT700 and +QT780, and 10 % and 40 J for +QT900. Annealed (+A) material is limited to 1100 MPa tensile and 320 HBW. ASTM A182 F6NM instead calls for 620 MPa (90 ksi) yield minimum, 790 MPa (115 ksi) tensile minimum, 15 % elongation, 45 % reduction of area and 295 HBW maximum.

Can 1.4313 forgings be supplied for NACE MR0175 sour service?

Yes. NACE MR0175 / ISO 15156-3 accepts wrought UNS S41500, the F6NM version of this steel, for sour service provided hardness does not exceed 23 HRC. Meeting that limit means a deliberate heat-treatment route rather than a single temper: austenitise at about 950–1050 °C, cool in air or oil, then double temper, first at roughly 650–690 °C and again at roughly 595–620 °C, so reverted austenite is stabilised and virgin martensite is not re-formed on cooling. The practical trade-off is strength, because holding hardness below 23 HRC generally caps yield strength well below the 800 MPa available in +QT900. Each sour-service order is supplied with hardness records and a manufacturer's compliance statement referencing the grade, the heat-treatment condition and the measured hardness.

What sizes of 1.4313 forgings can you make?

Seamless rings roll to 6,000 mm outside diameter on a 6 m radial-axial mill, with 3 m and 1 m mills for smaller sizes and an upset-and-punch route from OD 50 mm. The heaviest single forging is 30 tonnes, worked on 6,300 t, 4,000 t and 2,000 t hydraulic presses. Downstream limits are set by the shop: heat-treatment furnaces take work to 8,000 × 2,000 × 2,000 mm, two 15 m well-type furnaces allow long shafts to be quenched vertically, vertical lathes machine to Ø5,000 mm swing, horizontal lathes to 14,000 mm between centres, and the CNC deep-hole drilling machine bores Ø1,600 × 10,000 mm.

What is 1.4313 used for?

1.4313 is the standard steel for hydro-electric turbine runners, blades and shafts, where cavitation resistance, toughness and weld repairability matter more than maximum strength. It is also used for pump and compressor casings, shafts and impellers; valve bodies, bonnets, stems and seat rings; wellhead and Christmas tree components in sour service; steam and gas turbine parts; pressure-vessel flanges and tube sheets; and tooling and dies for pressure die casting. Its working window in the quenched and tempered condition runs from −60 °C to about +300 °C.

Is 1.4313 weldable?

Yes, and good weldability is the main reason the low-carbon 13Cr-4Ni grades displaced older 13 % Cr steels such as 1.4021 and 1.4057 in turbine and valve work. All arc processes can be used. Preheat of roughly 100–200 °C is usual, heavier sections benefiting from the upper end; shielding gases containing hydrogen or carbon should be avoided; and a matching filler or an E410NiMo-type consumable is normal. After welding the joint is tempered, or annealed and re-heat-treated, to restore toughness in the heat-affected zone. For sour service the HAZ hardness must also be held within the 23 HRC base-metal limit, which in practice means a qualified post-weld heat treatment.

What is the minimum order quantity and lead time for 1.4313 forgings?

The minimum order is 10 kg, with no minimum piece count, so a single small ring or one test bar is quotable as well as a one-off heavy forging. Normal lead time is 20 to 60 days from order confirmation. Standard 1.4313 melted through the electric arc furnace with ladle refining and vacuum oxygen decarburisation sits at the lower end; orders needing electroslag or vacuum arc remelting, third-party witnessed inspection to EN 10204 3.2, or corrosion testing placed with an outside laboratory sit at the upper end. Quotations are normally returned within two working days of receiving a drawing or specification.

Who supplies 1.4313 / X3CrNiMo13-4 forgings from China?

Jiangyin Jiangnan Metal Co., Ltd. is an integrated melting works and open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, operating since 1997 with 460 staff. Unlike a forging shop that buys billet, it melts its own steel, so a 1.4313 forging is traceable from the melt number rather than from a purchased billet certificate. The works holds CCS, BV, DNV, LR and NK approvals, issues EN 10204 3.1 certificates as standard and 3.2 witnessed certificates on request, and exports to North America, Europe, the Middle East and Asia-Pacific. Enquiries: sales@steelforgepieces.com, +86 189 2135 9659.

16. The manufacturer — company record

Jiangyin Jiangnan Metal Co., Ltd.Record reviewed 2026-09-22

Legal name: Jiangyin Jiangnan Metal Co., Ltd.
Business: Integrated steel melting works, open-die forge and ring rolling mill
Established: 1997
Plant address: No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Coordinates: 31.8330° N, 120.3510° E
Telephone / WhatsApp / WeChat: +86 189 2135 9659
Email: sales@steelforgepieces.com
Website: www.steelforgepieces.com
Employees: 460, including 9 senior engineers, 32 intermediate engineers and 140 technicians
Melting: EAF 25 t · LF 25 t / 50 t · VOD 30 t / 60 t · IF 2 / 8 / 25 t · VIM 3 t · ESR 3 / 6 t · VAR 6 t · max heat 60 t
Forging: Hydraulic presses 6,300 t / 4,000 t / 2,000 t · ring mills 6 m / 3 m / 1 m · hammers 5 t to 750 kg · max single piece 30 t
Heat treatment: 14 furnaces, car-bottom to 8,000 × 2,000 × 2,000 mm, two 15 m well-type furnaces, three high-temperature furnaces
Machining: Vertical lathes to Ø5,000 mm · horizontal lathes to Ø1,600 × 14,000 mm · CNC deep-hole drilling to Ø1,600 × 10,000 mm
Approvals: CCS · BV · DNV · LR · NK
Certification: EN 10204 3.1 as standard; EN 10204 3.2 witnessed by BV, DNV, LR, SGS, TÜV or the customer's inspector on request
Export markets: North America · Europe · Middle East · Asia-Pacific
Business hours: Monday–Saturday, 08:00–17:30 China Standard Time (UTC+8)
Getting here: Wuxi Shuofang International Airport 30 km · Shanghai airports 160 km · export ports Zhangjiagang and Shanghai

17. Standards referenced and how to cite this page

EN 10088-3:2023 — Stainless steels, Part 3: technical delivery conditions for semi-finished products, bars, rods, wire, sections and bright products of corrosion resisting steels for general purposes. Source of the 1.4313 composition and the +A / +QT700 / +QT780 / +QT900 property table. Supersedes EN 10088-3:2014 and :2005.
EN 10250-4 — Open die steel forgings for general engineering purposes, Part 4: stainless steels.
EN 10222-5 — Steel forgings for pressure purposes, Part 5: martensitic, austenitic and austenitic-ferritic stainless steels.
EN 10272 and EN 10028-7 — Stainless steel bars and flat products for pressure purposes.
ASTM A182/A182M — Forged or rolled alloy and stainless steel pipe flanges, forged fittings, and valves and parts for high-temperature service. Source of the Grade F6NM composition and mechanical requirements.
NACE MR0175 / ISO 15156-3 — Materials for use in H₂S-containing environments in oil and gas production, Part 3: cracking-resistant CRAs and other alloys. Source of the 23 HRC limit for wrought S41500 / S42400 and cast J91540.
EN 10204 — Metallic products: types of inspection documents (3.1 and 3.2 certificates).
ASTM A388, EN 10228-3, ASTM A370, ISO 6892, ASTM E23, ASTM E112, ASTM E415 — test methods applied to released forgings.

How to cite this page. Jiangyin Jiangnan Metal Co., Ltd. (2026). 1.4313 / X3CrNiMo13-4 forgings (ASTM A182 F6NM, UNS S41500): datasheet, equivalents and supply. Retrieved from https://www.steelforgepieces.com/Stainless-Steel/1.4313.html

Content owner and technical contact: Jiangyin Jiangnan Metal Co., Ltd., No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China · sales@steelforgepieces.com · +86 189 2135 9659.

Disclaimer: standard values are reproduced for reference and the governing edition of each standard prevails. Figures marked typ. are indicative literature values. Nothing on this page replaces a material specification, a design calculation or a mill certificate.

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