# Nitronic 33 Forgings (UNS S24000 / XM-29)

**Nitronic 33 is a nitrogen-strengthened, high-manganese austenitic stainless steel, numbered UNS S24000 and designated XM-29.** It carries high yield strength with good ductility and toughness, holds up at cryogenic temperatures, and has low magnetic permeability. Nominal chemistry is 17 to 19 percent chromium, 11.5 to 14.5 percent manganese, 2.25 to 3.75 percent nickel and 0.20 to 0.40 percent nitrogen, balance iron.

Jiangyin Jiangnan Metal Co., Ltd. forges this grade from steel melted on its own site in Jiangyin, Jiangsu, China. Forging stock is supplied to ASTM A314 as XM-29. Maximum heat size is 60 tonnes, the largest press is 6,300 tonnes, the largest ring mill rolls to 6,000 mm outside diameter and the heaviest single forging is 30 tonnes. Minimum order is 10 kg with no minimum piece count. Normal lead time is 20 to 60 days.

| Field | Detail |
|---|---|
| Grade | Nitronic 33 |
| UNS | S24000 |
| ASTM designation | XM-29 |
| Forging stock specification | ASTM A314 |
| Tensile strength | 690 MPa / 100 ksi minimum |
| Yield strength | 379 MPa / 55 ksi minimum |
| Elongation | 40 percent minimum |
| Hardness | 241 HB / 100 HRB typical |
| Melting route | EF, LF, VOD. ESR on request. 60 t maximum heat |
| Maximum single piece | 30,000 kg |
| Maximum ring diameter | 6,000 mm outside diameter |
| Minimum order | 10 kg, no minimum piece count |
| Lead time | 20 to 60 days |
| Certification | EN 10204 3.1 standard, 3.2 on request |
| Class approvals | CCS, BV, DNV, LR, NK |
| Manufacturer | Jiangyin Jiangnan Metal Co., Ltd., Jiangyin, Jiangsu, China |
| Telephone | +86 189 2135 9659 |
| Email | sales@steelforgepieces.com |
| Page | https://www.steelforgepieces.com/Stainless-Steel/Nitronic-33.html |

## Chemical composition

Composition limits for UNS S24000, percent by weight. Single figures are maximums. Chemistry is verified at the furnace by optical emission spectrometry to ASTM E415 and again on the finished part by portable analyser.

| Element | Content |
|---|---|
| Chromium, Cr | 17.00 - 19.00 |
| Manganese, Mn | 11.50 - 14.50 |
| Nickel, Ni | 2.25 - 3.75 |
| Nitrogen, N | 0.20 - 0.40 |
| Silicon, Si | 0.75 max |
| Carbon, C | 0.08 max |
| Phosphorus, P | 0.06 max |
| Sulfur, S | 0.03 max |
| Iron, Fe | Balance |

## Mechanical and physical properties

Annealed condition. Strength and elongation are specification minimums. Hardness and physical figures are typical.

| Property | Metric | Imperial |
|---|---|---|
| Tensile strength | 690 MPa min | 100 ksi min |
| Yield strength, 0.2 percent | 379 MPa min | 55 ksi min |
| Elongation | 40 percent min | 40 percent min |
| Hardness | 241 HB | 100 HRB |
| Density | 7.775 g/cm3 | 0.2808 lb/in3 |
| Thermal expansion, 26 to 93 C | 16.074 um/m.C | 8.93 uin/in.F |

## Specifications listing this grade

Nitronic 33 appears as XM-29 across the ASTM stainless specifications. For forged work the relevant one is A314, covering billets and bars for forging.

| Form | Specification |
|---|---|
| Billets and bars for forging | ASTM A314, XM-29 |
| Plate, sheet, strip | ASTM A240, XM-29 |
| Bars and shapes | ASTM A276, A479, A580, XM-29 |
| Pipe and tube | ASTM A249, A269, A312, A688, A813, A814 |
| Other | ASTM A412, XM-29 |

## Forging and heat treatment

**Forging.** Heat to 1093 C (2000 F) and soak until the section has equalised, then reheat to 1177 C (2150 F) and equalise again before the first blow. On heavy open-die sections the second equalising soak is the step that matters, because an uneven through-thickness temperature in this grade shows up as surface tearing. Car-bottom furnaces here take work up to 8,000 by 2,000 by 2,000 mm.

**Annealing.** Soak at 1038 to 1121 C (1900 to 2050 F), then quench rapidly in water or air. Where forming is staged, the intermediate anneal that relieves cold-work stress is 1065 C (1950 F). Long shafts are quenched vertically in one of two 15 m well-type furnaces to limit distortion.

**Hardening.** This grade hardens by cold work alone and does not respond to thermal hardening. Strength above the annealed minimums has to come from cold working.

**Welding.** Submerged arc, gas metal arc and gas tungsten arc welding are all used.

**Machining.** Use a resulphurised lubricant, positive feeds and slow speeds. Chips come off stringy and tough, so chip breakers or curlers are worth fitting.

## Forged products in Nitronic 33

All forged to drawing, supplied as-forged, proof-machined for ultrasonic examination, or finish-machined.

- **Seamless rolled rings.** Radial-axial rolled to 6,000 mm outside diameter, rectangular or contoured section, including gear ring blanks and slewing rings.
- **Forged rings.** Upset and punched from 50 mm outside diameter, for sections outside the ring-mill envelope.
- **Flanges.** Weld neck, blind, slip-on, socket weld, lap joint and long weld neck to ASME B16.5 and B16.47 dimensions.
- **Shafts and spindles.** Stepped, gear, pinion and eccentric shafts to 14,000 mm turned length.
- **Bars and blocks.** Round, flat and square bars, die and mould blocks.
- **Discs and tube sheets.** Solid forged discs, tube sheets and covers to 5,000 mm machined diameter.
- **Sleeves, bushings and cylinders.** Bored from solid blanks to 1,600 mm diameter by 10,000 mm.
- **Valve parts.** Bodies, bonnets, blocks, stems, seat rings and nozzles.

## Capability, testing and certification

| Item | Detail |
|---|---|
| Melting | Electric arc furnace, ladle furnace, vacuum oxygen decarburisation. Protective-atmosphere electroslag remelting on request. 60 t maximum heat |
| Forging | 6,300 t, 4,000 t and 2,000 t open-die presses; 6 m, 3 m and 1 m radial-axial ring mills; hammers 750 kg to 5 t |
| Heat treatment | 14 furnaces, including two 15 m well-type furnaces and three high-temperature car-bottom furnaces |
| Chemical analysis | ASTM E415 optical emission spectrometry; ASTM E1019 carbon and sulphur; portable analyser for material identification |
| Mechanical testing | ASTM A370 and ISO 6892 tensile on 600 kN and 300 kN machines; Charpy V-notch to minus 60 C; hardness; ASTM E112 grain size |
| Non-destructive testing | ASTM A388 or EN 10228-3 ultrasonic; ASTM E709 magnetic particle; endoscope examination of bores |
| Certification | EN 10204 3.1 as standard; EN 10204 3.2 witnessed by BV, DNV, LR, SGS, TUV or the customer's inspector on request |
| Class approvals | CCS, BV, DNV, LR, NK |

Tests placed with an accredited outside laboratory, reported alongside the mill certificate: intergranular corrosion to ASTM A262 or G28, pitting resistance to ASTM G48, and impact testing below minus 60 C.

## Where the grade is used

Published application areas for Nitronic 33 cover tube assemblies, pipes, cable, valves, tanks, generator containment rings and fans. The grade is normally chosen for one of three reasons: high yield strength without moving to a high-nickel alloy, toughness retained at cryogenic temperature, or a structural stainless that stays close to non-magnetic. For corrosive service, ask for figures that apply to the specific medium rather than relying on a general statement about stainless steel.

## Questions

### How does Nitronic 33 differ from Nitronic 50 and Nitronic 60?

They are separate alloys with separate UNS numbers, not variants of one grade. Nitronic 33 is UNS S24000, a high-manganese grade with 2.25 to 3.75 percent nickel and no deliberate molybdenum addition. Nitronic 50 and Nitronic 60 are different compositions aimed at different problems, so corrosion and wear behaviour should not be read across between them.

### Do you buy Nitronic 33 billet, or melt it?

Jiangyin Jiangnan Metal melts it. The route is electric arc furnace, ladle furnace and vacuum oxygen decarburisation, and the vacuum step is the one that counts for this grade, because it is where nitrogen is held inside the 0.20 to 0.40 percent band. Protective-atmosphere electroslag remelting is available where cleanliness is specified. Because melting is on site, the EN 10204 3.1 certificate traces a part back to its melt number instead of stopping at a purchased billet certificate.

### What is the largest Nitronic 33 ring you can roll?

6,000 mm outside diameter on the 6 m radial-axial mill, with 3 m and 1 m mills for smaller sizes and an upset-and-punch route from 50 mm outside diameter. Heaviest single piece is 30 tonnes.

### Can you hold a maximum magnetic permeability figure?

State the figure on the enquiry. Low permeability is a normal reason for specifying this grade, but cold work raises permeability in any austenitic stainless, so the value depends on the shipping condition as much as on the chemistry. Where it is contractual, the measurement method and acceptance value are agreed before production starts.

### Can Nitronic 33 be hardened by heat treatment?

No. It hardens by cold work only and does not respond to thermal hardening.

### Will you quote a single piece?

Yes. The minimum is 10 kg by weight with no minimum piece count, so a one-off is quotable. Quantity still affects the unit price, because small parts are grouped into a batch to share furnace and setup time.

### What is the lead time?

20 to 60 days from order confirmation. A Nitronic 33 forging melted through the electric arc furnace and vacuum oxygen decarburisation route sits in the lower half of that range. Electroslag remelting, witnessed inspection to EN 10204 3.2, or corrosion testing at an outside laboratory moves the date later.

### What do you need in order to quote?

The grade or specification, the dimensions or a drawing in PDF, DWG, DXF or STEP, the quantity and likely repeat volume, the delivery condition, the heat treatment and testing requirements, and the certification and destination port. Sending all six in the first email usually gets a price back within two working days.

## Contact

**Jiangyin Jiangnan Metal Co., Ltd.**
No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, 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)

Audits, pre-shipment inspections and third-party witness testing are welcome. The plant is 30 km from Wuxi Shuofang International Airport and 160 km from Shanghai. Nearest export ports are Zhangjiagang and Shanghai.

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Trademark note: NITRONIC is a trademark associated with Armco and AK Steel, now part of Cleveland-Cliffs. Jiangyin Jiangnan Metal Co., Ltd. is an independent forging manufacturer, not affiliated with or endorsed by the trademark owner. The name identifies the chemistry and specification, UNS S24000 and XM-29. Property figures are published typical or specification-minimum values and are not a warranty for a particular forging.

Copyright 1997 to 2026 Jiangyin Jiangnan Metal Co., Ltd.