# UNS S41500 Forgings (F6NM, Type 415, EN 1.4313)

**Supplier: Jiangyin Jiangnan Metal Co., Ltd., an integrated steel melting works and open-die forge at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. Operating since 1997. Telephone +86 189 2135 9659. Email sales@steelforgepieces.com.**

UNS S41500 is a low-carbon soft martensitic stainless steel of about 13% chromium, 4% nickel and 0.5% molybdenum, with carbon capped at 0.05%. The low carbon and the nickel addition suppress delta ferrite and give a structure of martensite plus retained austenite at room temperature, which produces 655 MPa minimum tensile strength together with good impact energy down to minus 60 degrees Celsius. The grade is air hardening, so heavy forged sections can be hardened with little risk of cracking. Forgings are ordered against ASTM A473 / ASME SA-473 or as ASTM A182 F6NM.

Page: https://www.steelforgepieces.com/Stainless-Steel/UNS-S41500.html
Last revised: 2026-10-08

## Designations

| System | Designation |
|---|---|
| UNS | S41500 |
| ASTM forging grade | A182 F6NM |
| Forging specification | ASTM A473, ASME SA-473 |
| Other names | Type 415, AISI 415, 13Cr-4Ni |
| EN 10088-1 | 1.4313, X3CrNiMo13-4 |
| Cast counterpart | CA6NM, UNS J91540 |
| AFNOR | Z6CN13-04, Z4CN13-4 |
| BS | 425C11, 425C12 |
| JIS (cast) | SCS5 |
| GB | 04Cr13Ni5Mo, 0Cr13Ni5Mo |
| SS | SS 2384 |

## Chemical composition, weight percent

Iron is the balance. Single values are maximum limits.

| Limit | C | Si | Mn | P | S | Cr | Ni | Mo |
|---|---|---|---|---|---|---|---|---|
| Minimum | - | - | 0.50 | - | - | 11.50 | 3.50 | 0.50 |
| Maximum | 0.05 | 0.60 | 1.00 | 0.030 | 0.030 | 14.00 | 5.50 | 1.00 |

Source: Special Quality Alloys F6NM datasheet, cross-checked against the Virgamet 1.4313 comparison table.

EN 1.4313 is narrower: 12.0 to 14.0% Cr, 3.5 to 4.5% Ni, 0.3 to 0.7% Mo, with a nitrogen minimum of 0.02%. A heat certified to S41500 does not automatically meet 1.4313.

## Mechanical properties, hardened and double tempered

| Property | Value |
|---|---|
| Tensile strength, Rm | 95 ksi min, 655 MPa |
| 0.2% proof stress, Rp0.2 | 75 ksi min, 517 MPa |
| Elongation | 18% min |
| Reduction of area | 35% min |
| Charpy V-notch at -60 C | 40 J (30 ft-lbf); 42 J average / 34 J single on one mill datasheet |
| Hardness, sour service | 23 HRC maximum per NACE MR0175 / ISO 15156 |

## EN 1.4313 quenched and tempered classes

| Condition | Rm (MPa) | Rp0.2 (MPa) | Elongation | KV (J) |
|---|---|---|---|---|
| +A annealed | under 1100 | - | - | under 320 HBW |
| +QT650 | 700 to 850 | over 520 | over 15% | over 70 |
| +QT780 | 780 to 980 | over 620 | over 15% | over 70 |
| +QT900 | 900 to 1100 | over 800 | over 12% | over 50 |
| +QT to EN 10028-7 | 780 to 980 | over 650 | over 14% | over 70 |

Proof stress at temperature, MPa minimum: +QT650 gives 500 at 100 C, 460 at 300 C and 450 at 350 C. +QT780 gives 590 at 100 C, 530 at 300 C and 515 at 350 C. +QT900 gives 720 at 100 C and 620 at 300 C. Modulus of elasticity is 195 GPa at 100 C, 185 GPa at 200 C, 175 GPa at 300 C and 170 GPa at 400 C.

Source: Virgamet.

A part specified as F6NM to NACE and a part specified as 1.4313 +QT900 are the same alloy in very different conditions, and the second cannot meet 23 HRC. State the condition or strength class on the order.

## Physical properties

| Property | Value |
|---|---|
| Density | 7.8 g/cm3, 490 lb/ft3 |
| Elastic modulus | 200 GPa, 28 x 10^6 psi |
| Shear modulus | 76 GPa |
| Poisson's ratio | 0.28 |
| Shear strength | 550 MPa |
| Fatigue strength | 430 MPa |
| Thermal conductivity | 24 W/m-K |
| Thermal expansion | 10 micrometre/m-K; 10.5 at 100 C to 11.6 at 400 C |
| Specific heat capacity | 480 J/kg-K |
| Latent heat of fusion | 270 J/g |
| Melting range | 1400 C solidus to 1450 C liquidus |
| Electrical conductivity | 2.7% IACS equal volume |

Sources: MakeItFrom AISI 415 (S41500); expansion against temperature from Virgamet.

Service temperature is quoted differently by different sources. Virgamet describes components operating to about 300 C. MakeItFrom lists a maximum corrosion temperature of 390 C and a maximum mechanical temperature of 780 C. For pressure parts, follow the design code allowables. Corrosion resistance is described as medium in media with only low chloride content, so this grade is not a substitute for duplex or 6Mo alloys in seawater.

## Heat treatment

| Operation | Temperature | Cooling |
|---|---|---|
| Forging and rolling | 1150 C | Air |
| Annealing (+A) | 600 to 650 C | Air or furnace |
| Hardening | 950 to 1050 C | Oil or air |
| Temper for +QT900 | 520 to 580 C | Air |
| Temper for +QT780 | 550 to 600 C | Air |
| Temper for +QT650 | 650 to 700 C then 600 to 620 C | Air, two stages |

Source: Virgamet.

## Sour service and the 23 HRC limit

NACE MR0175 limits 13Cr-4Ni alloys to 23 HRC maximum for sour service and calls for a double temper after quenching, with the first temper between 650 and 690 C and the second between 595 and 620 C. The first cycle recovers as-quenched martensite and forms reverted austenite. The second recovers any virgin martensite formed when that austenite destabilised on cooling.

Published work on industrial heats adds three points that matter in practice. The usual hardness conversion does not hold for this alloy: BS 860 and ASTM E140 put 23 HRC at about 253 HV, but researchers working on 13Cr-4Ni-(Mo) treat 23 HRC as roughly 275 HV. An intermediate cool between the two tempers helps reduce hardness, while a sub-zero treatment at minus 30 C after tempering raises hardness again by destabilising retained austenite. And composition inside the allowed band changes the outcome: a heat at 0.027% C and 180 ppm N could be brought close to 23 HRC, a heat at 0.030% C and 280 ppm N stayed near 300 HV under the same cycles, and a heat at 0.018% C and 68 ppm N reached 21.4 HRC with 583 MPa yield and 751 MPa tensile. For hardness-critical orders, specify a carbon and nitrogen ceiling rather than relying on the grade limits.

Reference: De Sanctis M., Lovicu G., Varone A., Richetta M., Buccioni M., Donato A., Study of 13Cr-4Ni-(Mo) (F6NM) Steel Grade Heat Treatment for Maximum Hardness Control in Industrial Heats, Metals 7(9):351, 2017.

## Welding

Published sources disagree. A mill datasheet for F6NM describes the grade as having a high level of corrosion resistance and weldability. Virgamet states that 1.4313 is not suitable for welding. Both reflect the same position: the alloy can be welded only under a qualified procedure with controlled preheat, matched consumables and post-weld heat treatment, and post-weld heat treatment on 13Cr-4Ni is known to be difficult to bring below 23 HRC in the heat affected zone. Advise at enquiry stage if the forging will be welded.

## Forged forms available in UNS S41500

All forged from steel melted on site. No purchased billet, no castings, no welded fabrications.

- Seamless rolled rings, OD 50 mm to OD 6,000 mm, rectangular or contoured section, including gear ring blanks, slewing rings and valve seat rings
- Forged round, flat and square bars, die blocks and mould blocks
- Hollow bars, sleeves, bushings, couplings, barrels, casings and cylinders bored from solid, to 1,600 mm diameter by 10,000 mm
- Flanges: weld neck, blind, slip-on, socket weld, lap joint, orifice, anchor, girth and long weld neck, to ASME B16.5, B16.47 and API 6A
- Discs, tube sheets and covers to 5,000 mm machined diameter, proof-machined for volumetric inspection
- Valve and wellhead parts: bodies, bonnets, stems, seat rings, spools, nozzles, manifolds. API 6A and NACE MR0175 / ISO 15156
- Shafts, spindles, rolls and rotors to 14,000 mm turned length, with a 15 m pit furnace for vertical quench
- Hydro turbine runner, blade and casing forgings

## Applications

Valves and actuators, subsea and downhole tooling, and turbine, pump and compressor components in the oil, chemical, metallurgical and power industries, including parts exposed to high and low temperatures. UNS S41500 and its cast counterpart CA6NM are both widely used for the manufacture and repair of hydraulic turbine runners, and for blades and casings in hydroelectric and thermal plant.

## Works capability

| Field | Detail |
|---|---|
| Legal name | Jiangyin Jiangnan Metal Co., Ltd. |
| Business | Integrated melting works, open-die forge, ring rolling mill |
| Established | 1997 |
| Employees | 460, including 9 senior engineers, 32 intermediate engineers, 140 technicians |
| Plant | No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China |
| Melting | EF, LF, VOD, VIM, VAR, ESR |
| Forging | 6,300 t press, 6 m radial-axial ring mill, 30 t maximum single piece |
| Approvals | CCS, BV, DNV, LR, NK |
| Minimum order | 10 kg, no minimum piece count |
| Lead time | 20 to 60 days |
| Telephone | +86 189 2135 9659 |
| Email | sales@steelforgepieces.com |

## What we need to quote

Specification and revision, delivery condition or strength class, finished and rough dimensions with machining allowance, quantity, NDT and impact test requirements including test temperature, and whether NACE MR0175 / ISO 15156 compliance is mandatory.

## References

1. ASTM A473, Standard Specification for Stainless Steel Forgings. https://store.astm.org/a0473-21.html
2. Special Quality Alloys, F6NM datasheet. https://www.specialqualityalloys.com/media/j50lssei/f6nm.pdf
3. Virgamet, 1.4313 X3CrNiMo13-4 / F6NM / UNS S41500. https://virgamet.com/offer/1-4313-x3crnimo134-f6nm-uns-s41500-z6cn1304-425c11-stainless-steel
4. MakeItFrom, AISI 415 (S41500) stainless steel. https://www.makeitfrom.com/material-properties/AISI-415-S41500-Stainless-Steel
5. De Sanctis M. et al., Metals 7(9):351, 2017. https://www.mdpi.com/2075-4701/7/9/351
6. voestalpine Specialty Metals, F6NM. https://www.voestalpine.com/specialtymetals/en/products/f6nm/

Data compiled for engineering reference. Material is supplied against the purchase order specification and the EN 10204 3.1 certificate issued for the actual heat.