# UNS S24100 (XM-28 / Nitronic 32) Open-Die Forgings

**UNS S24100, designated XM-28 by ASTM and sold under the trade name Nitronic 32, is a low-nickel, nitrogen-strengthened chromium-manganese austenitic stainless steel. It carries 11 to 14 percent manganese and 0.20 to 0.45 percent nitrogen in place of most of the nickel found in Type 304, and delivers approximately twice the yield strength of Type 304 with broadly comparable corrosion resistance.**

Jiangyin Jiangnan Metal Co., Ltd. melts and forges this grade in one works at Jiangyin, Jiangsu, China: seamless rolled rings, forged rings, flanges, round bars, shafts, discs, sleeves, bushings, tube sheets and valve components, to ASTM A314, ASTM A276 and ASTM A580, with EN 10204 3.1 or 3.2 certification.

Contact: sales@steelforgepieces.com | +86 189 2135 9659

## Grade summary

| Field | Detail |
|---|---|
| UNS number | S24100 |
| ASTM designation | XM-28 |
| Trade name | Nitronic 32 (registered trademark of AK Steel) |
| Alloy family | Nitrogen-strengthened chromium-manganese austenitic stainless steel |
| Specifications | ASTM A314, ASTM A276, ASTM A580, ASTM A313 |
| Mill product forms | Ingot, forging billet, bar, plate |
| Minimum tensile, annealed | 690 MPa / 100 ksi |
| Minimum 0.2% yield, annealed | 379 MPa / 55 ksi |
| Magnetic permeability | 1.008 annealed, 1.011 after 70% cold draw |
| Supplier | Jiangyin Jiangnan Metal Co., Ltd., Jiangyin, Jiangsu 214423, China |
| Minimum order | 10 kg, no minimum piece count |
| Lead time | 20 to 60 days |

## Correction on grade naming

Older listings for this grade, including an earlier version of this page, paired UNS S24100 with AISI 310H. That pairing is wrong. AISI 310H is a 25 chromium, 20 nickel heat-resisting grade. UNS S24100 is a low-nickel, high-manganese, nitrogen-bearing grade. They share neither chemistry nor service behaviour and cannot be substituted for one another. The correct equivalents for UNS S24100 are ASTM XM-28 and the trade name Nitronic 32.

## Chemical composition, weight percent

Published limits differ slightly between sources. Electralloy's data sheet gives 16.50 to 19.00 percent chromium and 0.045 percent phosphorus maximum; the wider UNS listing gives 16.5 to 19.5 percent chromium and 0.06 percent phosphorus maximum.

| Element | Electralloy data sheet | UNS listing | Function |
|---|---|---|---|
| Carbon | 0.15 max | 0.15 max | Strength; the high limit is why sensitisation must be avoided |
| Manganese | 11.00 to 14.00 | 11 to 14 | Austenite stabiliser replacing most of the nickel |
| Chromium | 16.50 to 19.00 | 16.5 to 19.5 | Passive film, corrosion resistance |
| Nickel | 0.50 to 2.50 | 0.5 to 2.5 | Austenite stability and toughness, kept low |
| Nitrogen | 0.20 to 0.45 | 0.2 to 0.45 | Principal strengthener |
| Silicon | 1.00 max | 1 max | Deoxidiser |
| Phosphorus | 0.045 max | 0.06 max | Residual |
| Sulfur | 0.030 max | 0.03 max | Residual |
| Iron | Balance | Balance | Matrix |

## Mechanical properties, annealed, ASTM A276

| Property | Metric | Imperial |
|---|---|---|
| Ultimate tensile strength, min | 690 MPa | 100 ksi |
| 0.2% offset yield strength, min | 379 MPa | 55 ksi |
| Elongation, min | 30% | 30% |
| Reduction of area, min | 50% | 50% |
| Hardness, typical annealed bar | 92 HRB | 92 HRB |

Annealed Type 304 is normally specified at 515 MPa tensile and 205 MPa yield, which is the basis for the comparison stated above.

## Physical properties

| Property | Value | Condition |
|---|---|---|
| Density | 7.781 g/cm3 (0.281 lb/in3) per Electralloy; 7.83 g/cm3 (0.283 lb/in3) per the UNS listing | Room temperature |
| Melting range | 1418 to 1446 C (2585 to 2635 F) per Electralloy; 1450 to 1510 C quoted elsewhere | - |
| Modulus of elasticity | 200 GPa (29 x 10^6 psi) | 21 C / 70 F |
| Specific heat | 0.12 Btu/lb/F | 0 to 100 C |
| Electrical resistivity | 27.6 microhm-in | 21 C / 70 F |
| Thermal expansion, mean | 9.4 x 10^-6 /F over 23 to 204 C; 10.7 x 10^-6 /F over 23 to 649 C; 11.6 x 10^-6 /F over 23 to 982 C | From room temperature |
| Magnetic permeability | 1.008 annealed; 1.011 after 70% cold draw | H = 200 Oe, 70 F |

## Forging, heat treatment and fabrication

- **Hot working.** 1121 to 1204 C, or 2050 to 2200 F. A common practice is to heat to 1093 C (2000 F), soak to equalise, then raise to 1177 C (2150 F) and equalise before forging.
- **Annealing.** 1038 to 1121 C (1900 to 2050 F), commonly 1066 C (1950 F), followed by rapid cooling in water or air. In-process anneals run 1900 to 2000 F.
- **Hardening.** The grade does not harden by heat treatment. Strength above the annealed condition comes from cold work.
- **Machining.** Machinability is about 30 percent of AISI B1112. Characteristics resemble Type 304, but higher strength and rapid work hardening call for lower cutting rates, positive feeds and abundant resulfurised lubricant.
- **Welding.** Gas tungsten arc, gas metal arc, shielded metal arc and submerged arc. Preheat is not required.
- **Forming.** The same methods used with other austenitic stainless steels. Well suited to simple cold-headed parts needing high mechanical properties.

## Corrosion behaviour

In weak acid solutions and pitting media the corrosion resistance of UNS S24100 approaches that of Type 304. In more aggressive media it is somewhat less corrosion resistant than Type 304. Because of its higher carbon content it is less resistant to intergranular attack than Type 304 and will not pass ASTM A262 testing after sensitisation at 1250 F.

UNS S24100 is therefore not the right choice for warm chloride-bearing seawater systems, strong sulphuric or mixed acid duty, or sour service under NACE MR0175 / ISO 15156. For those environments, super duplex (ASTM A182 F53 or F55), 6Mo (A182 F44), 904L or a nickel alloy such as Inconel 625 is appropriate.

## Applications

| Application | Property being used | Forged form |
|---|---|---|
| Clamps for pole line hardware | High strength in cold-headed parts | Forged blanks, bar |
| Concrete reinforcing accessories | Strength with non-magnetic behaviour | Forged bar |
| Shafting | Twice the yield of 304 at lower nickel content | Forged shafts, spindles |
| Dam gate stems | Strength and fresh-water corrosion resistance | Forged round bar |
| Skid wire for underground transmission lines | Non-magnetic, abrasion resistant | Ingot, forging billet |
| Abrasion and corrosion-resistant screens | Rapid work hardening | Forged frames and rings |
| High strength non-magnetic springs, wire forms | Permeability near 1.01 after cold work | Billet to ASTM A313 and A580 |
| Racks, cages, fasteners, communication hardware | Alternative to 300-series grades | Forged blanks, discs, sleeves |

## Manufacturing capability for this grade

Steel is melted on site rather than purchased as billet. Carbon, alloy, stainless and duplex grades run through the 25 t electric arc furnace with 25 t and 50 t ladle refining and 30 t or 60 t vacuum oxygen decarburisation, the route used to hold nitrogen and carbon where the specification wants them. Protective-atmosphere electroslag remelting at 3 t and 6 t is available where cleanliness also governs on nitrogen-alloyed steels.

| Product | Size limit | Set by |
|---|---|---|
| Seamless rolled rings | OD 50 mm to OD 6,000 mm | 6 m, 3 m and 1 m radial-axial ring mills |
| Forged shafts | up to 14,000 mm turned length | C61160 horizontal lathe; 15 m well furnace |
| Discs, tube sheets, blocks | up to 5,000 mm machined diameter | 5,000 mm vertical turning lathe |
| Bored sleeves, hollow shafts | up to 1,600 mm dia x 10,000 mm | CNC deep-hole drilling machine |
| Single-piece weight | up to 30,000 kg | 60 t heat size; 6,300 t press |

Forms produced: seamless rolled rings and contoured rolled rings, forged rings, weld neck and blind and slip-on flanges, forged round bars and blocks, stepped and eccentric shafts, discs and tube sheets, sleeves and bushings, hollow forged cylinders, and valve bodies, bonnets, stems and seat rings.

## Testing and certification

Optical emission spectrometry to ASTM E415, infrared carbon and sulfur analysis to ASTM E1019, handheld positive material identification, tensile testing to ASTM A370 on 600 kN and 300 kN machines, Charpy V-notch impact testing to minus 60 C, ultrasonic examination to ASTM A388 and EN 10228-3, magnetic particle inspection to ASTM E709, and grain size to ASTM E112. Certificates to EN 10204 3.1, or 3.2 witnessed by BV, DNV, LR, SGS, TUV or the customer's inspector. Intergranular corrosion testing to ASTM A262 or G28 is placed with an accredited third-party laboratory where a specification calls for it. Works approvals: CCS, BV, DNV, LR, NK.

## Frequently asked questions

### Is UNS S24100 the same as AISI 310H?

No. UNS S24100 is XM-28, also known as Nitronic 32, a low-nickel chromium-manganese austenitic stainless steel with 11 to 14 percent manganese and 0.20 to 0.45 percent nitrogen. AISI 310H is a high-chromium, high-nickel heat-resisting grade. The two are not interchangeable.

### Is UNS S24100 the same as Nitronic 32?

Yes. Nitronic 32 is the trade name under which UNS S24100 / ASTM XM-28 is sold. Nitronic is a registered trademark of AK Steel.

### How strong is UNS S24100 compared with Type 304?

ASTM A276 requires, in the annealed condition, a minimum 0.2 percent yield strength of 379 MPa (55 ksi) and a minimum tensile strength of 690 MPa (100 ksi). That is approximately double the yield strength normally specified for annealed Type 304, achieved through nitrogen in solution rather than added nickel.

### Can UNS S24100 be hardened by heat treatment?

No. It takes no hardening response from heat treatment. Strength above the annealed condition comes from cold work. Heat treatment is limited to annealing at 1038 to 1121 C followed by rapid cooling.

### Is UNS S24100 suitable for seawater or strong acid service?

Generally no. Corrosion resistance approaches Type 304 in weak acids and pitting media but is lower than Type 304 in more aggressive media, and the higher carbon content leaves the grade open to intergranular attack once sensitised.

### Is UNS S24100 magnetic?

It is essentially non-magnetic. Relative permeability is 1.008 annealed and 1.011 after a 70 percent cold draw, at H = 200 oersteds and 70 F.

### What temperature should UNS S24100 be forged at?

1121 to 1204 C, or 2050 to 2200 F. A common practice is to heat to 1093 C (2000 F), equalise, then raise to 1177 C (2150 F) and equalise again before forging. In-process annealing runs 1900 to 2000 F.

### Which specifications can UNS S24100 forgings be certified to?

ASTM A314 for forging billet and bar, ASTM A276 for bars and shapes, ASTM A580 and A313 for wire. EN 10204 3.1, or 3.2 countersigned by a third party on request.

### What is the minimum order and lead time?

10 kg with no minimum piece count, so a single part is quotable. Lead time is 20 to 60 days from order confirmation.

## Data sources

- Electralloy, Nitronic 32 Austenitic Stainless Steel Alloy (UNS S24100, XM 28) product data sheet, revision 2-2019.
- AZoM, Super Alloy Nitronic 32 (UNS S24100).
- Ulbrich Stainless Steels and Special Metals, Nitronic 32 alloy page.

Values shown are typical or specification minima and do not constitute a warranty of performance in any particular application. Confirm against the certified mill test report for the heat supplied.

## Request a quotation

Jiangyin Jiangnan Metal Co., Ltd.
No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province 214423, China
Telephone, WhatsApp and WeChat: +86 189 2135 9659
Email: sales@steelforgepieces.com
Business hours: Monday to Saturday, 08:00 to 17:30 China Standard Time (UTC+8)

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Copyright 1997 to 2026 Jiangyin Jiangnan Metal Co., Ltd. Nitronic is a registered trademark of AK Steel, used here for identification only. Page last reviewed 5 October 2026.