# Nitronic 50 Forgings — UNS S20910 / XM-19 / 1.3964

**UNS S20910 is a chromium-manganese-nickel-molybdenum stainless steel strengthened with 0.20 to 0.40 per cent nitrogen. Annealed, it is specified at 690 MPa minimum tensile, 380 MPa minimum yield and 35 per cent elongation, roughly twice the yield strength of 304 or 316, with a pitting resistance equivalent number near 34 against about 25 for 316L.**

Supplied by Jiangyin Jiangnan Metal Co., Ltd., an integrated melting works and open-die forge in Jiangyin, Jiangsu, China, operating since 1997. We melt the grade ourselves on the EAF, ladle furnace and VOD route, then forge or ring-roll, heat treat, machine and test on one site, so the certificate traces to the melt number rather than to a purchased billet.

| Field | Detail |
|---|---|
| UNS | S20910 |
| ASTM generic | XM-19; FXM-19 for forgings under ASTM A182 |
| European | 1.3964, closely related but not identical in every detail |
| Type | Austenitic, nitrogen-strengthened, non-magnetic |
| Density | 7.88 to 7.89 g/cm³ |
| Magnetic permeability | Below 1.010, annealed |
| Forging temperature | 1150 to 1205 °C |
| Annealing | 1065 to 1120 °C, rapid cool, not hardenable by heat treatment |
| Sour service | Listed in NACE MR0175 / ISO 15156 and NACE MR0103 |
| Supplier contact | sales@steelforgepieces.com, +86 189 2135 9659 |

## Chemical composition

ASTM A182 grade FXM-19 forging limits, weight per cent, balance iron. Plate written to ASTM A240 restricts silicon tighter at 0.75 per cent maximum.

| Limit | C | Mn | Si | P | S | Cr | Ni | Mo | N | Nb | V |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Min | — | 4.00 | — | — | — | 20.50 | 11.50 | 1.50 | 0.20 | 0.10 | 0.10 |
| Max | 0.06 | 6.00 | 1.00 | 0.040 | 0.030 | 23.50 | 13.50 | 3.00 | 0.40 | 0.30 | 0.30 |

Nitrogen and manganese do the strengthening; the 11.5 to 13.5 per cent nickel keeps the structure fully austenitic. Remove that nickel and the microstructure moves toward duplex, with higher strength but lower toughness.

## Specified minimum properties, annealed

AMS 5764 and ASTM A182 FXM-19.

| Property | Imperial | Metric |
|---|---|---|
| Tensile strength | 100 ksi min | 690 MPa min |
| Yield, 0.2 % offset | 55 ksi min | 380 MPa min |
| Elongation, 2 in or 4D | 35 % min | 35 % min |
| Reduction of area | 55 % min | 55 % min |
| Magnetic permeability | Below 1.010, annealed | Below 1.010, annealed |

## Typical tensile behaviour, annealed

| Temperature | Tensile | Yield 0.2 % | Elongation |
|---|---|---|---|
| −196 °C | 1558 MPa / 226 ksi | 883 MPa / 128 ksi | 40 % |
| −73 °C | 1007 MPa / 146 ksi | 586 MPa / 85 ksi | 50 % |
| 24 °C | 827 MPa / 120 ksi | 448 MPa / 65 ksi | 45 % |
| 316 °C | 717 MPa / 104 ksi | 317 MPa / 46 ksi | 36 % |
| 427 °C | 676 MPa / 98 ksi | 310 MPa / 45 ksi | 30 % |
| 538 °C | 621 MPa / 90 ksi | 283 MPa / 41 ksi | 40 % |

## Strain-hardened levels, bar product

| Level | Diameter | Tensile min | Yield min | Elong. min | RA min |
|---|---|---|---|---|---|
| 1 | 0.125–4.00 in | 110 ksi | 90 ksi | 35 % | 55 % |
| 2 | 0.125–4.00 in | 135 ksi | 105 ksi | 20 % | 50 % |
| 3 | 0.125–3.50 in | 160 ksi | 130 ksi | 15 % | 45 % |
| 4 | 0.062–2.00 in | 180 ksi | 145 ksi | 12 % | 45 % |
| 5 | 0.062–1.50 in | 200 ksi | 180 ksi | 10 % | 45 % |

For sour service the NACE hardness ceiling governs which level is acceptable. On heavy forgings the achievable condition depends on section size and reduction route.

## Thermal data

| Range from 24 °C | Expansion, µm/m·°C | At temperature | Conductivity, W/m·K |
|---|---|---|---|
| to 93 °C | 16.2 | 93 °C | 14.3 |
| to 204 °C | 16.7 | 204 °C | 16.3 |
| to 316 °C | 17.3 | 316 °C | 17.9 |
| to 427 °C | 17.9 | 427 °C | 19.5 |
| to 538 °C | 18.4 | 538 °C | 21.1 |
| to 760 °C | 19.6 | 760 °C | 24.3 |

Electrical resistivity about 820 microhm·mm at 24 °C.

## Corrosion behaviour

Good in many reducing and oxidising acids, in chlorides and in pitting environments, including seawater, boiling 65 per cent nitric acid, ferric sulphate-sulphuric acid and ammonium carbamate. It can still stress corrosion crack in hot chlorides; in boiling 42 per cent magnesium chloride it resists cracking about as well as 316. Annealing at the low end of the range gives higher mechanical properties with good corrosion resistance, while the high end suits as-welded material going into strongly corrosive media, where it reduces the risk of intergranular attack.

## Fabrication notes

Machining is harder than 316: slower speeds, higher feeds, sharp tools, and the edge must stay cutting rather than riding the surface. Chips are tough and stringy, so chip breakers help. Forming follows normal austenitic practice but needs more force, with in-process annealing at 1065 to 1120 °C where work is severe. Welding uses conventional stainless processes with ER209 filler, also sold as Nitronic 50W, which gives a joint at base-metal strength; 3 to 5 per cent nitrogen in the shielding gas is beneficial, and 316L filler can be used where lower joint strength is acceptable. Raise electron beam or laser welding with us first, since the nitrogen content can cause outgassing in autogenous high-energy-density welds.

## Product forms

| Forged form | Usual specification | Typical duty |
|---|---|---|
| Seamless rolled rings | AMS 5764, ASTM A182 FXM-19 | Valve seat rings, pump casings, gear ring blanks, waste canister rings |
| Forged flanges | ASTM A182 FXM-19, ASME B16.5 and B16.47 | Seawater and urea piping, offshore topsides, subsea connectors |
| Bars, shafts, spindles | ASTM A479, A276, AMS 5764 | Pump shafts, valve stems, eccentric shafts, gearbox and turbine shafts |
| Discs and covers | AMS 5764 | Blind flanges, closure plates, pressure-retaining covers |
| Tubes, sleeves, bushings | AMS 5764, ASTM A182 FXM-19 | Wear sleeves, liners, stuffing boxes, deep-sea chambers |
| Tube sheets | ASTM A240 XM-19 equivalents | Heat exchangers in chemical, fertiliser, pulp and paper plant |
| Valve and wellhead parts | ASTM A182 FXM-19, API 6A, NACE MR0175 | Bodies, bonnets, stems, spools, nozzles for trees, wellheads, BOPs |
| Fastener blanks | ASTM A193 B8R, ASTM A194 Grade 8 | High-strength corrosion-resistant bolting |

## Specifications referencing S20910

AMS 5764, AMS 5861, ASTM A182 FXM-19, ASTM A240 and ASME SA-240 XM-19, ASTM A276, ASTM A312, ASTM A314, ASTM A403, ASTM A412, ASTM A479, ASTM A580, ASTM F1314, ASTM A193 Grade B8R, ASTM A194 Grade 8, AWS A5.9 ER209, NACE MR0175 / ISO 15156, NACE MR0103. Inspection and certification: EN 10228-3, SEP 1921, ASTM A388, EN 10204 3.1 and 3.2.

## Manufacturing capability

| Item | Capability |
|---|---|
| Melting | EAF, ladle furnace, VOD, VIM, VAR, ESR; 60 t maximum heat |
| Forging | 6,300 t, 4,000 t and 2,000 t open-die presses |
| Ring rolling | Radial-axial mills at 1 m, 3 m and 6 m; rings to 6,000 mm OD |
| Heat treatment | 14 furnaces, car-bottom to 8,000 mm, well furnaces 15,000 mm deep |
| Machining | Vertical lathes to 5,000 mm swing, horizontal to 14,000 mm, deep-hole drilling to 1,600 mm × 10,000 mm |
| Maximum single piece | 30 t |
| Minimum order | 10 kg, no minimum piece count |
| Lead time | 20 to 60 days |
| Approvals | CCS, BV, DNV, LR, NK |

## Common questions

**What is Nitronic 50 equivalent to?** The same material as UNS S20910 and ASTM XM-19, written FXM-19 for forgings under ASTM A182, and closely corresponding to European 1.3964. The two designations are commonly treated as interchangeable but are not identical in every detail.

**Is it stronger than 316?** Yes. Annealed S20910 carries a specified minimum yield of 380 MPa, roughly double annealed 304 or 316, with typical annealed yield near 448 MPa at room temperature.

**Can it be used in sour service?** It is listed in NACE MR0175 / ISO 15156 and NACE MR0103 for resistance to sulphide stress cracking. Qualification depends on meeting the hardness limit and environmental limits in the standard, which are decided by supplied condition and section size.

**What forging and annealing temperatures apply?** Forging at 1150 to 1205 °C, with published mill guidance extending to 1232 °C. Solution annealing at 1065 to 1120 °C followed by rapid cooling. Not hardenable by heat treatment.

**Why is it hard to machine?** It work-hardens quickly. Speeds down, feeds up, rigid set-up, tool always engaged. Solution-annealed material machines more easily than strain-hardened.

**What sizes can be made?** Rings to 6,000 mm outside diameter, shafts to 14,000 mm turned length, discs and tube sheets to 5,000 mm machined diameter, bored cylinders to 1,600 mm × 10,000 mm, single pieces to 30 t. Minimum order 10 kg.

## Contact

Jiangyin Jiangnan Metal Co., Ltd.
No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Telephone +86 189 2135 9659
Email sales@steelforgepieces.com
Page: https://www.steelforgepieces.com/Stainless-Steel/Nitronic-50.html

## Sources

ATI technical data sheet for ATI 50 / ATI XM-19 (UNS S20910); ASTM A182/A182M grade FXM-19; Cleveland-Cliffs Armco Nitronic 50 product data bulletin; Langley Alloys grade notes on Nitronic 50; Aircraft Materials Nitronic 50 data sheet; voestalpine Specialty Metals notes on 1.3964 / Alloy 50 / XM-19; Midalloy ER209 product bulletin.

Nitronic is a registered trademark of AK Steel Corporation, part of Cleveland-Cliffs Inc. Jiangyin Jiangnan Metal Co., Ltd. is not affiliated with or licensed by the trademark holder; the name identifies the generic grade UNS S20910 / ASTM XM-19. Values here are for comparison; acceptance values are those of the purchase order and applicable standard. Revised 3 October 2026.