# X9CrNiSiNCe21-11-2 (1.4835 / UNS S30815) Open-Die Forgings

**X9CrNiSiNCe21-11-2 is the EN name for heat resisting austenitic stainless steel 1.4835, standardised in DIN EN 10095:2018-12 and equivalent to UNS S30815.**

The alloy holds 20.0-22.0% chromium, 10.0-12.0% nickel and 1.40-2.50% silicon, with 0.12-0.20% nitrogen and 0.03-0.08% cerium. The base is close to 1.4828 (AISI 309); what changes the behaviour is the higher nitrogen and the rare earth cerium. Nitrogen raises strength and creep resistance. Cerium keeps the chromium oxide scale bonded to the metal when temperature swings quickly, which is the normal failure mode for plain CrNiSi steels in cyclically fired plant.

Highest application temperature in air is 1150 C. The grade is used above 550 C against hot gases and products of combustion, with warranted scaling resistance under wide and fast thermal fluctuation. It has no resistance in a reducing atmosphere.

Jiangyin Jiangnan Metal Co., Ltd. melts and forges this grade at one site in Jiangyin City, Jiangsu Province, China.

## Grade identification

| Field | Detail |
|---|---|
| EN name | X9CrNiSiNCe21-11-2 |
| EN material number | 1.4835 |
| UNS | S30815 |
| ISO 4955 | X7CrNiSiNCe21-11 |
| ASTM | A240 S30815, A479 S30815 |
| Common name | 253MA |
| Further listing | X10CrNiSiN21-11 |
| Related EN grade | 1.4893, X8CrNiSiN21-11 (nitrogen, no cerium) |
| Current standard | DIN EN 10095:2018-12, superseding 1999-05 |
| Type | Heat resisting austenitic chromium-nickel-silicon steel |

Mill trade names recorded against this grade include Therma 253 MA (Outokumpu), Avesta 253 MA, RA 253 MA, BGH 4835 (BGH Edelstahl Siegen) and Permodur 4835 (Deutsche Edelstahlwerke). Those marks belong to their owners. Jiangyin Jiangnan Metal has no affiliation with them and supplies forgings made to the EN 1.4835 or UNS S30815 specification.

## Chemical composition, mass %

Two sets of limits exist and they are not identical. Confirm which applies before enquiry.

| Specification | C | Si | Mn | P | S | Cr | Ni | N | Ce |
|---|---|---|---|---|---|---|---|---|---|
| EN 1.4835 | 0.05-0.12 | 1.40-2.50 | <1.00 | <0.045 | <0.015 | 20.00-22.00 | 10.00-12.00 | 0.12-0.20 | 0.030-0.080 |
| UNS S30815 | 0.05-0.10 | 1.40-2.00 | <0.80 | <0.040 | <0.030 | 20.00-22.00 | 10.00-12.00 | 0.14-0.20 | 0.030-0.080 |
| ISO X7CrNiSiNCe21-11 | 0.05-0.10 | 1.40-2.00 | <0.80 | <0.040 | <0.030 | 20.00-22.00 | 10.00-12.00 | 0.14-0.20 | 0.030-0.080 |

Balance iron. Molybdenum, titanium, niobium, vanadium, tungsten and aluminium are not specified alloying elements. One proprietary version permits Mo below 0.54%.

## Mechanical properties, annealed +AT at 20 C

| Property | Symbol | Value |
|---|---|---|
| Tensile strength | Rm | 650-850 MPa |
| Proof stress 0.2% | Rp0.2 | 310 MPa |
| Elongation | A | >37% |
| Elongation, longitudinal | A5 | >40% |
| Brinell hardness | HB 30 | <210 HB |
| Modulus of elasticity | E | 200 kN/mm2 |

Some trade listings quote a minimum yield of 345 MPa for this grade. The EN 10095 figure is 310 MPa, and tensile strength is a band rather than an open minimum. A tighter contractual yield can be agreed on the order and proved on the certificate, but it is not an automatic property of 1.4835.

## Physical properties at 20 C

| Property | Symbol | Value |
|---|---|---|
| Density | rho | 7.80 kg/dm3 |
| Specific heat capacity, 20-100 C | cp | 500 J/kg·K |
| Thermal conductivity | lambda | 15 W/m·K |
| Electrical resistivity | rho | 0.85 ohm·mm2/m |
| Linear expansion, 20-100 C | alpha | 17.0-19.5 x 10^-6 K^-1 |
| Magnetisability | - | None in annealed condition |

## Creep data, MPa

Rz is creep rupture strength, R1 is the 1% creep limit, subscripts are hours. These figures govern load-bearing design. The 1150 C figure describes scaling behaviour, not load capacity.

| Property | 600 C | 700 C | 800 C | 900 C | 1000 C |
|---|---|---|---|---|---|
| Rz/1000 | 238 | 105 | 50 | 24 | 12 |
| Rz/10000 | 157 | 63 | 27 | 13 | 7 |
| Rz/100000 | 88 | 35 | 15 | 8 | 4 |
| R1/1000 | 170 | 66 | 31 | 15.5 | 8 |
| R1/10000 | 126 | 45 | 19 | 10 | 5 |
| R1/100000 | 80 | 26 | 11 | 6 | 3 |

## Heat treatment

| Process | Temperature | Time | Cooling |
|---|---|---|---|
| Softening / solution annealing | 1020-1120 C | 5-20 min | Fast, air or water |
| Stress relief annealing | 850-950 C | <30 min | Fast, in air |
| Thermo-mechanical treatment | 900-1150 C | - | Air |

Solution annealing is the delivery condition. Stress relief at 850-950 C will not restore a solution annealed structure after forging and does not replace it. Orders listing only the stress relief cycle are a common cause of certificate disputes, so we query them before production.

## Forging, welding and machining

Hot working runs 900-1150 C. The nitrogen addition makes the steel stiffer to deform than 304 or 309, so press force, reheat scheduling and bite size must account for it; an under-powered press produces centre cracking rather than a sound forging. Hot bending is carried out at 850-1100 C. Plasticity is much better than that of ferritic steels.

Cold working is straightforward but needs more force than a conventional austenitic grade, and the steel springs back, so compensation is required. Parts that will later run above 800 C should be annealed after cold bending.

Welding is by coated electrode arc, pure argon, plasma and MIG. TIG and MIG give the best creep resistance at high temperature. A suitable filler is 1.4842. No preheat or post-weld heat treatment is normally needed.

Sulphur is below 0.015% in the EN version, so the steel is not free-machining and work-hardens quickly. Use sharp rigid tooling, positive rake, reduced surface speed and a heavy uninterrupted feed.

## Forged product range and size limits

| Product | Size limit | Set by |
|---|---|---|
| Seamless rolled rings | OD 50-6000 mm | 6 m radial-axial ring mill; upset and punch below mill range |
| Forged rings, retaining rings, seat rings | to OD 6000 mm | 6300 t press |
| Forged flanges | to OD 6000 mm | Press and ring mill |
| Discs, tube sheets, covers | to 5000 mm machined diameter | 5000 mm vertical lathe |
| Shafts, spindles, eccentric shafts | to 14000 mm turned length | C61160 lathe, 15 m well furnace |
| Sleeves, bushings, hollow cylinders | to 1600 mm dia x 10000 mm | CNC deep-hole drilling machine |
| Round bars, blocks | per drawing | Press and hammers |
| Nozzles, manifolds, valve bodies and bonnets | per drawing | Press and machine shop |
| Single piece weight | to 30000 kg | 60 t heat size, 6300 t press |

Minimum order 10 kg, no minimum piece count. Lead time 20-60 days.

## Applications

Furnace components, hood annealing and muffle furnaces, lifting bar furnaces, heat treatment furnace tubes, charging cages, insert boxes and sealing sheets. Recuperators, radiator and radiant tubes, air heating tubes in sulphuric acid gas converters, high-temperature heat exchangers. Combustion nozzles, burner components and heavily loaded parts of waste gas detoxification plant. Styrene reactors and convection tubes. Hot-zone hardware in steelworks, glass and cement plant. Thermocouple tubes and protection sheaths.

## Service limits

1.4835 resists heat. It is not a general corrosion resisting steel.

| Condition | Behaviour | Consider instead |
|---|---|---|
| Contact with water | Not rated. Corrosion resistance is reduced against standard austenitic steels and is not given in combination with water. | 316L, 1.4462 duplex, 904L |
| Reducing atmosphere | No resistance | Nickel alloys selected for the atmosphere |
| Oxidising sulphuric gases | Low resistance | Alloy 600 and 601 family |
| Chloride, seawater, subsea | Not suitable | A182-F53, A182-F55, A182-F44 |
| Below 550 C in service | Outside intended range | Standard austenitic or alloy steel |
| Sustained load near 1150 C | Scaling limit, not load limit. Creep strength at 1000 C is single-figure MPa. | Alloy 602, Haynes 230, Inconel 601 |

One supplier datasheet for 1.4835 states the grade should not be used for forging. Other published datasheets list forged and cast parts as a normal delivery form and give a hot working range of 900-1150 C, which is the position we work to. If an inspector raises the objection, we will set out the forging and annealing route proposed for the part before any steel is melted.

## Manufacturer

| Field | Detail |
|---|---|
| Legal name | Jiangyin Jiangnan Metal Co., Ltd. |
| Business | Integrated melting works, open-die forge and ring rolling mill |
| Established | 1997 |
| Employees | 460, including 9 senior engineers, 32 intermediate engineers and 140 technicians |
| Plant | No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China |
| Melting | EF, LF, VOD, VIM, VAR, ESR. 60 t maximum heat |
| Forging | 6300 t press, 6 m ring mill, 30 t maximum single piece |
| Heat treatment | 14 furnaces, including high-temperature car-bottom and 15 m deep well furnaces |
| Approvals | CCS, BV, DNV, LR, NK |
| Volumetric NDT | EN 10228-3, SEP 1921, ASTM A388 |
| Certification | EN 10204-3.1, or 3.2 witnessed by a third party |
| Minimum order | 10 kg, no minimum piece count |
| Lead time | 20 to 60 days |
| Telephone | +86 189 2135 9659 |
| Email | sales@steelforgepieces.com |
| Page | https://www.steelforgepieces.com/Stainless-Steel/X9CrNiSiNCe21-11-2.html |

## Standards referenced

DIN EN 10095:2018-12 (superseding 1999-05), EN 10088-1, ISO 4955, ASTM A240, ASTM A479, EN 10228-3, SEP 1921, ASTM A388, EN 10204.

Figures are compiled for engineering guidance from the current standard and published mill datasheets. Confirm every design-critical value against the governing standard and your own design code before use.