Grade data
Identification and headline properties for Nitronic 30.
- UNS number
- S20400
- Structure
- Austenitic
- Strengthened by
- N and Mn
- Molybdenum
- None
- Tensile, min
- 655 MPa
- Yield, min
- 330 MPa
Nitronic 30 gives about 50 percent higher yield strength than Type 304L, so lighter sections
can carry the same load. It work hardens quickly and still holds good ductility. Nickel is held
at 1.5 to 3.0 percent and no molybdenum is added, which makes it a low cost grade for wet
abrasive and moderate water service rather than a high alloy corrosion grade.
Where not to use it. Nitronic 30 is not a seawater, subsea, desalination or
strong acid alloy and does not replace duplex or 6 Mo grades. For chloride bearing seawater,
firewater, subsea pipework and FGD service, specify
A182 F51,
F53,
F55,
F44,
904L or
Alloy 31.
We forge all of these grades as well.
Chemical composition
Composition limits for UNS S20400 in weight percent, iron balance.
Nitronic 30 / UNS S20400 composition limits, wt %
| Element | Min | Max |
|---|
| Carbon (C) | – | 0.03 |
| Manganese (Mn) | 7.0 | 9.0 |
| Phosphorus (P) | – | 0.040 |
| Sulfur (S) | – | 0.030 |
| Silicon (Si) | – | 1.00 |
| Chromium (Cr) | 15.0 | 17.0 |
| Nickel (Ni) | 1.50 | 3.00 |
| Nitrogen (N) | 0.15 | 0.30 |
| Copper (Cu) | – | 1.00 |
| Iron (Fe) | Balance |
Manganese in S20400 is 7.0 to 9.0 percent. Some published tables show manganese as 15.0 to
17.0 percent, which simply repeats the chromium range. Our mill certificates state the 7.0 to
9.0 percent range.
Mechanical properties
Specified minimums and typical room temperature values.
Specified minimums, annealed (ASTM A666, UNS S20400)
ASTM A666 minimum mechanical requirements for UNS S20400, annealed
| Property | Imperial | Metric |
|---|
| Tensile strength, min | 95 ksi | 655 MPa |
| Yield strength 0.2 percent, min | 48 ksi | 330 MPa |
| Elongation in 2 in., min | 35 % | 35 % |
Typical room temperature values
Typical annealed properties for Nitronic 30
| Property | Typical |
|---|
| Ultimate tensile strength | 110 ksi (758 MPa) |
| Yield strength, 0.2 percent offset | 55 ksi (379 MPa) |
| Elongation in 2 in. | 50 % |
| Hardness | 95 HRB |
ASTM A666 and ASTM A240 cover sheet, strip, plate and flat bar, not forgings, and there is no
separate ASTM forging specification for S20400. We certify forgings to S20400 chemistry and
agree the mechanical acceptance values, test location and test direction on the order.
Forging and heat treatment
Parameters used in our forging shop for this grade.
Nitronic 30 forging, annealing and machining parameters
| Operation | Parameters |
|---|
| Melting | EAF plus VOD as standard, ESR on request |
| Forging | Heat to 1093 °C (2000 °F) and soak, raise to 1176 °C (2150 °F), equalise, then forge |
| Annealing | Soak at 1038 to 1121 °C (1900 to 2050 °F), then cool rapidly in water or air |
| Hardening | By cold work only, the grade does not harden by heat treatment |
| Machining | Same methods and tooling as 300 series austenitic stainless, positive rake, slower speeds, sulphurised lubricant, chip breakers and curlers because the chips are stringy and tough |
Corrosion, wear and magnetic behaviour
Corrosion resistance
Pitting resistance measured in 10 percent FeCl3 solution is better than Type 304.
In sulfuric acid and hydrochloric acid the grade is much better than Types 409 and 410 and
approaches Type 304 in more dilute solutions.
Wet abrasion
Corrosive wear resistance is high under a range of sliding conditions. Stainless steels as a
class resist abrasion far better than AR steels once conditions are even mildly corrosive, and
Nitronic 30 is more cost effective than Types 409 and 304 in wet abrasive duty.
Magnetic response
Unlike the other nitrogen strengthened Nitronic grades, Nitronic 30 undergoes magnetic
transformation when cold worked, because deformation martensite forms. That martensite raises
strength, work hardening rate and abrasion resistance, but the grade should not be chosen where
the part must stay non-magnetic after forming.
Effect of cold reduction on ferrite number
| Cold work, % | 0 | 10 | 20 | 30 | 40 |
|---|
| Ferrite number |
0 | 3 | 10 |
21 | 27 |
|---|
Welding
Nitronic 30 can be fusion welded with the arc processes normally used for austenitic stainless
steels, with good ductility and toughness and resistance to weld cracking without preheat or
postheat. A small amount of ferrite forms in autogenous welds, which holds down hot cracking
sensitivity. Parameters follow the other Nitronic grades rather than standard austenitics, with
slower travel speed and a hotter shielding gas for GTAW, argon plus 5 percent hydrogen or helium.
Standard austenitic fillers or the AWS A5.9 and A5.4 Nitronic fillers 209, 240, 218 and 219 can
be used. Matching weld wire is UNS S20980, AWS A5.9 Class ER209.
Forged products in Nitronic 30
Product forms and service for Nitronic 30 forgings
| Forged form | Service |
|---|
| Seamless rolled rings, forged rings |
Magnetic ore separator screens, bulk solids handling equipment, wear rings |
| Round bars, shafts, spindles |
Mechanical and structural parts needing high strength with wet abrasion resistance |
| Flanges, tube sheets, sleeves, bushings |
Water supply and water control structures, sewage treatment plant equipment |
| Discs, blanks, gears, rolls |
Coal buckets, hoppers, hopper cars, chutes and chute liners |
| Open-die blocks and custom forgings |
Truck and bus frames, rapid transit structures, refrigerated truck rear frames, shipboard container structures, food processing equipment |
Tensilised Nitronic 30 has been used in rapid transit structures where a strength to weight
ratio up to three times that of carbon steel improves operating efficiency. Other uses include
hose clamps, safety belt anchors and fasteners.
Sizes are made to drawing. Send the drawing or dimensions with quantity and the required
certification and we will confirm feasibility, price and delivery.
Testing and certification
Ultrasonic testing is carried out to EN 10228-4, which is the part covering
austenitic and austenitic-ferritic stainless steel forgings. EN 10228-3 applies to ferritic and
martensitic forgings and does not apply to this grade. ASTM A388 and SEP 1921 can also be
applied on request.
Certificates are issued to EN 10204 3.1, or EN 10204 3.2 with third party witness such as BV,
SGS, TUV, LR or DNV. Chemical analysis, tensile, hardness, impact, grain size, PMI, liquid
penetrant examination and a dimensional report are available.
Questions we are asked about this grade
What is Nitronic 30?
Nitronic 30, designated UNS S20400, is a nitrogen and manganese strengthened
austenitic stainless steel containing 15.0 to 17.0 percent chromium, 7.0 to 9.0 percent
manganese, 1.5 to 3.0 percent nickel and 0.15 to 0.30 percent nitrogen. It was developed for
applications requiring a good level of aqueous corrosion resistance combined with good
toughness, wet abrasion resistance and low alloy cost.
Is Nitronic 30 magnetic?
In the annealed condition it is essentially non-magnetic, with a ferrite
number of 0. Unlike the other nitrogen strengthened Nitronic grades it undergoes magnetic
transformation when cold worked, because deformation martensite forms. Ferrite number reaches
about 3 at 10 percent cold work and about 27 at 40 percent cold work, so it should not be used
where the finished part must stay non-magnetic after forming.
How does Nitronic 30 compare with Type 304?
It gives about 50 percent higher yield strength than Type 304L and better
pitting resistance than Type 304 in 10 percent ferric chloride solution, at lower alloy cost
because nickel is only 1.5 to 3.0 percent. In sulfuric and hydrochloric acid it is much better
than Types 409 and 410 and approaches Type 304 in more dilute solutions. It is also more cost
effective than Types 409 and 304 in wet abrasive service.
What is the forging temperature for Nitronic 30?
Heat to 1093 degrees C, 2000 degrees F, and soak to equalise, then raise to
1176 degrees C, 2150 degrees F, and equalise before forging. After forging, anneal by soaking
at 1038 to 1121 degrees C, 1900 to 2050 degrees F, followed by rapid cooling in water or
air.
Which standards cover Nitronic 30?
The grade is identified as UNS S20400. Flat products are covered by ASTM
A240, ASTM A666 and ASME SA240, and matching weld wire is UNS S20980, AWS A5.9 Class ER209.
There is no dedicated ASTM forging specification for S20400, so forgings are certified to
S20400 chemistry with mechanical acceptance criteria agreed on the purchase order.
Can Nitronic 30 be used in seawater or subsea service?
No. The grade contains no molybdenum and only 1.5 to 3.0 percent nickel, so
it is not intended for seawater, subsea, desalination or aggressive chloride service. For those
duties use a duplex, super duplex or 6 molybdenum grade such as A182 F51, F53, F55, F44, 904L
or Alloy 31.
Who forges Nitronic 30 parts?
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1
Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. It produces Nitronic
30, UNS S20400, forged rings, seamless rolled rings, flanges, round bars, shafts, discs,
sleeves, bushings and tube sheets to customer drawing, with EN 10204 3.1 or 3.2 certificates.
Telephone 0086-189-2135-9659, email sales@steelforgepieces.com.
References
Composition, typical mechanical properties, corrosion behaviour, cold work ferrite data and
weldability follow the Cleveland-Cliffs product data sheet for Nitronic 30 Stainless Steel and
ASM International Alloy Digest SS-1138. Minimum mechanical requirements follow ASTM A666 for
UNS S20400. Ultrasonic acceptance follows EN 10228-4 for austenitic and austenitic-ferritic
stainless steel forgings.
NITRONIC is a registered trademark of Cleveland-Cliffs Inc., successor to AK Steel.
Jiangyin Jiangnan Metal Co., Ltd. is an independent forging manufacturer and is not affiliated
with, endorsed by or sponsored by the trademark owner. Grade names identify the material
specification supplied.