What 1.4893 is
1.4893 is the material number for X8CrNiSiN21-11, an austenitic chromium-nickel-silicon steel alloyed with nitrogen and cerium for service at high temperature. The same material is sold as 253 MA, RA 253 MA, UNS S30815, SS 2368 and EN 1.4835 (X9CrNiSiNCe21-11-2), and published grade sheets list 1.4893 and X8CrNiSiN21-11 among the alternative designations for that group.
Which number to order against. The grade carried in the chemical composition tables of EN 10095 is 1.4835, and its limits are a little wider than the S30815 limits usually quoted against 1.4893. State the number your drawing uses together with the specification you are buying to, and the analysis will be confirmed against both before the heat is tapped.
The steel is intended for use above 550 °C, with 850 to 1100 °C the range it suits best. Around 21 % chromium and 1.4 to 2.0 % silicon build a protective Cr2O3 layer, the cerium addition helps that layer stay attached through thermal cycling, and the nitrogen addition raises strength at temperature while reducing the tendency to sigma phase embrittlement. The result is oxidation performance in the class of the 25/20 grades at a lower nickel content, which is the reason buyers specify it.
| Material number | 1.4893 |
|---|---|
| EN name | X8CrNiSiN21-11 |
| Also designated | 253 MA, RA 253 MA, UNS S30815, SS 2368, EN 1.4835, X9CrNiSiNCe21-11-2, X7CrNiSiNCe21-11 |
| Type | Austenitic heat resisting steel, nitrogen and cerium alloyed |
| Nominal analysis | 21 % Cr, 11 % Ni, 1.6 % Si, 0.17 % N, 0.05 % Ce |
| Service range | Above 550 °C; best suited 850 to 1100 °C |
| Maximum temperature in air | 1150 °C, EN 10095 table B.2, guidance only, for 1.4835 |
| Hot working | 900 to 1150 °C |
| Softening anneal | 1020 to 1120 °C, 5 to 20 min, fast cool in air or water |
| Stress relief | 850 to 950 °C, under 30 min |
| Density | 7.80 kg/dm3 |
| Magnetic response | Non-magnetic; can become slightly magnetic after cold work or welding |
| Forged forms supplied | Rings, rolled rings, flanges, discs, tube sheets, bars, blocks, sleeves, bushings, hollow cylinders, shafts, valve parts |
Chemical composition
Two sets of limits are in circulation and they do not match. The narrower set follows the UNS S30815 and ISO style of specification and is the one most often printed against 1.4893. The wider set is what EN 10095 permits for 1.4835. Both are given so you can see which one your drawing calls up. Figures are percent by mass; a single figure is a maximum.
| C | Si | Mn | P | S | Cr | Ni | Ce | N | Fe |
|---|---|---|---|---|---|---|---|---|---|
| 0.05–0.10 | 1.40–2.00 | 0.80 | 0.040 | 0.030 | 20.00–22.00 | 10.00–12.00 | 0.030–0.080 | 0.14–0.20 | Balance |
| C | Si | Mn | P | S | Cr | Ni | Ce | N | Fe |
|---|---|---|---|---|---|---|---|---|---|
| 0.05–0.12 | 1.40–2.50 | 1.00 | 0.045 | 0.015 | 20.00–22.00 | 10.00–12.00 | 0.03–0.08 | 0.12–0.20 | Balance |
Molybdenum, titanium, niobium, tungsten, vanadium, aluminium and copper are not intentionally added. Under EN 10095 no unlisted element may be intentionally added without the purchaser's agreement. Because the steel for these forgings is melted on site rather than bought in as billet, nitrogen and cerium can be aimed inside your specification band instead of being accepted as delivered on somebody else's certificate. Where the duty is severe scaling, holding silicon and nitrogen toward the top of the range can be agreed at enquiry stage.
Mechanical and physical properties
Room temperature requirements below are the EN 10095 values for 1.4835 in the solution annealed condition (+AT). For heavy open-die forgings the test location and acceptance values are agreed on the order, because section thickness changes the cooling rate through solution treatment and therefore the properties recorded at the test piece.
| Property | Symbol | Value |
|---|---|---|
| Proof strength 0.2 % | Rp0.2 | 310 N/mm2 min. |
| Proof strength 1.0 % | Rp1.0 | 350 N/mm2 min. |
| Tensile strength | Rm | 650 to 850 N/mm2 |
| Elongation | A | 40 % min. |
| Hardness | HB | 210 max., guidance only |
| Density | ρ | 7.80 kg/dm3 |
| Specific heat, 20 to 100 °C | cp | 500 J·kg-1·K-1 |
| Linear expansion, 20 to 100 °C | α | 17.0 to 19.5 × 10-6 K-1 |
| Thermal conductivity at 20 °C | λ | 15 W·m-1·K-1 |
| Electrical resistivity | ρ | 0.85 × 10-4 Ω·cm |
Creep data
Creep decides whether a part reaches its design life, so the figures are given in full rather than summarised. Values in MPa.
| Criterion | 600 °C | 700 °C | 800 °C | 900 °C | 1000 °C |
|---|---|---|---|---|---|
| Rz / 1 000 h | 238 | 105 | 50 | 24 | 12 |
| Rz / 10 000 h | 157 | 63 | 27 | 13 | 7 |
| Rz / 100 000 h | 88 | 35 | 15 | 8 | 4 |
| R1 / 1 000 h | 170 | 66 | 31 | 15.5 | 8 |
| R1 / 10 000 h | 126 | 45 | 19 | 10 | 5 |
| R1 / 100 000 h | 80 | 26 | 11 | 6 | 3 |
Corrosion and atmosphere behaviour
EN 10095 table B.2 gives a maximum service temperature in air of 1150 °C for 1.4835, a figure the standard itself marks as guidance only. In practice the limit is often set by strength rather than by scaling, so check the creep table above against your design stress before taking the 1150 °C figure at face value.
In sulphur bearing gases the grade keeps up with the aluminium bearing ferritics 1.4742 and 1.4762 despite being austenitic, which is unusual and is one of the reasons it appears in sulphuric acid gas converters. In carburising and nitriding atmospheres it behaves well, but AISI 310 and AISI 314 (1.4841 type) are still clearly better and should be considered where carburising dominates the duty.
Not a wet corrosion alloy. For seawater, chloride, acid or sour service to NACE MR0175 / ISO 15156 the correct families are duplex and super duplex, 904L, Alloy 20 and the nickel alloys. See A182 F55, 904L and Incoloy 825.
Forging, heat treatment, machining and welding
Hot working runs between 900 and 1150 °C. Softening annealing is 1020 to 1120 °C for 5 to 20 minutes with fast cooling in air or water, which restores the austenitic structure and puts precipitates back into solution. Stress relief, where a drawing calls for it, is 850 to 950 °C for under 30 minutes. Hot bending is carried out at 850 to 1100 °C.
The nitrogen addition that gives the steel its hot strength also makes it stiffer to deform than plain 18/8, so forging passes are planned with more press force and tighter control of finishing temperature than a 304 type grade needs. On cold forming the steel springs back and the tooling has to compensate; after cold bending, parts that will run above 800 °C are usually annealed before service.
Machining follows normal high alloy austenitic practice: sharp tools, rigid setups, reduced surface speed and a positive feed heavy enough to cut under the work hardened skin rather than rub on it. Sulphur is held low for cleanliness and weldability, so the steel is not free machining and cycle times should be estimated against 310 rather than against 303 or 316.
Welding is done with coated electrodes, TIG, MIG and plasma. TIG and MIG give the best creep performance in the joint. Use filler metal of matching 253 MA / 1.4835 type.
Where 1.4893 forgings are used
This is furnace and flue gas hardware. The duties listed are those documented for the 253 MA / 1.4835 group, grouped by the forged form we supply.
| Forged form | Application |
|---|---|
| Rings and rolled rings | Turbine and fan rotor rings, CFBC boiler components, heat treatment stands and fixtures, furnace roll rings |
| Flanges | Recuperator and heat exchanger flanges, exhaust manifold flanges, hot gas ducting |
| Tube sheets and discs | Tube sheets and covers for recuperators and heat exchangers, ash hopper covers |
| Hollow cylinders, sleeves, bushings | Thermocouple tubes, tubular guards, radiator and air heating pipe sections, burner components |
| Shafts and spindles | Furnace fan shafts, roller hearth and walking beam furnace shafts, continuous annealing lines |
| Valve bodies and seat rings | Hot gas valves, dampers and slide gates in flue gas and incineration service |
| Bars and blocks | Fireproof and refractory anchors, pipe hooks, grate bars, machined furnace hardware |
Plant types where the grade is found include sulphuric acid gas converters, combustion chambers, heat treatment furnaces, impact separators, glass foundry moulds, styrene reactors and convection tubes, and the steelworks, glass and cement industries.
Supply of 1.4893 forgings
Jiangyin Jiangnan Metal Co., Ltd. is an integrated steel melting and open-die forging works in Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, operating since 1997. For a grade held to a 0.06 point nitrogen window and a 0.05 point cerium window, melting in house is the difference between controlling the analysis and inheriting it. Steel is melted, refined, forged or ring rolled, heat treated, machined and tested without leaving the site, so the certificate traces back to the melt number rather than stopping at a purchased billet.
| Melting | 25 t electric arc furnace, 25 t and 50 t ladle furnaces, 30 t and 60 t vacuum oxygen decarburisation. Maximum heat 60 t. VIM, VAR and protective atmosphere ESR available where a grade needs remelting. |
|---|---|
| Forging | Hydraulic open-die presses 6,300 t, 4,000 t and 2,000 t; hammers 750 kg to 5 t |
| Ring rolling | Radial-axial mills to 6,000 mm, 3,000 mm and 1,000 mm OD; rings from OD 50 mm by upset and punch |
| Heat treatment | 14 furnaces, including three high temperature car-bottom furnaces for solution treatment and two 15 m well furnaces for vertical quenching of long shafts |
| Machining | Vertical lathes to 5,000 mm swing, horizontal lathes to 14,000 mm, CNC deep hole drilling 1,600 × 10,000 mm |
| Single piece weight | Up to 30,000 kg |
| Testing on site | Optical emission spectrometry to ASTM E415, PMI, tensile to ASTM A370 and ISO 6892, Charpy with low temperature bath, ultrasonic to ASTM A388 and EN 10228-3, magnetic particle to ASTM E709, grain size to ASTM E112 |
| Class approvals | CCS, BV, DNV, LR, NK |
| Certification | EN 10204 3.1 as standard; EN 10204 3.2 witnessed by BV, DNV, LR, SGS, TUV or your own inspector on request |
| Minimum order | 10 kg, no minimum piece count |
| Lead time | 20 to 60 days |
| Quotation | Within two working days of a drawing or specification |
What to send with an enquiry
A firm price needs six things: the grade as your drawing states it, whether that is 1.4893, X8CrNiSiN21-11, 1.4835, 253 MA or S30815; dimensions or a drawing in PDF, DWG, DXF or STEP; quantity and likely repeat volume; delivery condition, meaning as-forged, proof machined or finish machined; heat treatment and testing requirements including any ultrasonic acceptance class; and the certification level and destination port.
Quotation for 1.4893 forgings
No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. Customer audits and third party inspection are welcome.
Questions we are asked about 1.4893
Is 1.4893 the same as 253 MA?
They are treated as one material family. Grade sheets list 1.4893 and X8CrNiSiN21-11 among the alternative designations for 253 MA and UNS S30815, alongside EN 1.4835 and X9CrNiSiNCe21-11-2. The number carried in the EN 10095 composition tables is 1.4835, and its limits are slightly wider than the S30815 style limits normally printed against 1.4893. Quote the number on your drawing and the specification, and the analysis will be confirmed against both.
What is the UNS equivalent of 1.4893?
UNS S30815. Other names for the same material are 253 MA, RA 253 MA, SS 2368, EN 1.4835 and X9CrNiSiNCe21-11-2.
What is the maximum service temperature?
1150 °C in air per the guidance table B.2 of EN 10095 for 1.4835. The steel is designed for duty above 550 °C and suits 850 to 1100 °C best. Where load is carried, the creep figures above will set the limit before scaling does.
At what temperature is 1.4893 forged?
Hot working at 900 to 1150 °C, then softening annealing at 1020 to 1120 °C for 5 to 20 minutes with fast cooling in air or water. Stress relief is 850 to 950 °C for under 30 minutes. More press force per pass is needed than for a standard 18/8 austenitic because of the nitrogen content.
Can 1.4893 be used in seawater or sour service?
No. It is a heat resisting grade for oxidising and combustion atmospheres above 550 °C, not a wet corrosion alloy. For seawater, chloride or NACE MR0175 service use duplex, super duplex, 904L, Alloy 20 or a nickel alloy.
Is 1.4893 magnetic?
It is non-magnetic in the annealed condition and can become slightly magnetic after cold working or welding.
What is the smallest order you will take?
10 kg, with no minimum piece count, so a single ring or a one-off shaft can be quoted. Small parts are normally grouped into a batch to share furnace and setup time, which is why quantity still moves the unit price.
Data sources
Composition and mechanical limits are quoted from EN 10095 as published in the British Stainless Steel Association property tables and in supplier grade sheets for X9CrNiSiNCe21-11-2 / 1.4835 / 253 MA / UNS S30815. Creep values and heat treatment windows are from the same grade sheets. Maximum service temperature in air is from EN 10095 table B.2, which the standard marks as guidance only. Values here are for selection purposes; order acceptance criteria are those written on the purchase order and the mill certificate.