1.4835 Material Equivalent: UNS S30815, X9CrNiSiNCe21-11-2 Heat-Resistant Stainless Steel

What 1.4835 Is and What It Equals

Grade 1.4835 is the EN designation of a heat-resistant austenitic chromium-nickel steel with the EN name X9CrNiSiNCe21-11-2 and the UNS number S30815. In the marketplace it is usually sold under its well-known commercial heat-resistant designation, and the practical equivalent list for procurement is short and specific:

EN 1.4835 / X9CrNiSiNCe21-11-2 (European designation)

UNS S30815 (American designation)

AISI 253MA-type heat-resistant austenitic stainless steel (commercial designation)

Related product specifications: EN 10095 for heat-resisting steels, ASTM A240 / A176 for plate and strip, and ASME Section II for pressure-retaining applications

It is important to understand what 1.4835 is not. It is not a substitute for grade 310S, and it is not a molybdenum-bearing corrosion grade. The alloy is designed for hot, oxidising environments where a conventional austenitic steel would scale away or sag, and it achieves that through micro-alloying rather than through a large nickel or molybdenum addition.

Chemical Composition and the Cerium Correction

Element	1.4835 / X9CrNiSiNCe21-11-2 / UNS S30815
C (carbon)	0.05 – 0.12%
Si (silicon)	1.40 – 2.50%
Mn (manganese)	≤ 1.00%
P (phosphorus)	≤ 0.045%
S (sulfur)	≤ 0.015%
Cr (chromium)	20.0 – 22.0%
Ni (nickel)	10.0 – 12.0%
N (nitrogen)	0.12 – 0.20%
Ce (cerium)	0.03 – 0.08%
Mo (molybdenum)	Not specified / not required

A frequent error in published property tables is to list nitrogen twice and omit cerium altogether. The two alloying elements are different and both matter. Nitrogen, at 0.12 – 0.20%, is a strong solid-solution strengthener and is the main reason the grade holds high creep strength with a comparatively modest nickel content. Cerium, at roughly 0.03 – 0.08%, is a rare-earth micro-addition that improves the adherence of the protective oxide scale, which is exactly what prevents spalling during repeated heating and cooling. Silicon, at 1.40 – 2.50%, is unusually high for an austenitic steel and works with the cerium to build a dense, self-healing oxide. Remove the cerium from the specification and the cyclic oxidation performance that defines the grade is lost.

Physical and Mechanical Properties

Property	Typical value
Density	7.8 kg/dm³
Magnetic behaviour	Non-magnetic in the annealed condition
Thermal conductivity at 20 °C	about 15 W/(m·K)
Electrical resistivity at room temperature	about 0.85 Ω·mm²/m
0.2% proof strength Rp0.2 (minimum)	310 MPa
Tensile strength Rm	650 – 850 MPa
Elongation A80 (minimum)	37%

The mechanical profile is that of a strong, moderately ductile austenitic steel: a 310 MPa minimum proof strength and a 650 – 850 MPa tensile range, well above the levels quoted for plain 304 or 316 grades, with elongation still comfortably above 35%. The material is non-magnetic after annealing, but welded or heavily cold-worked areas can show slight magnetism, which is normal for an austenitic grade and does not indicate a defect. One practical restriction applies: the grade is not intended for forging, and product forms should be obtained as sheet, coil, tube, bar or wire rather than forged components.

Heat Resistance and Oxidation Behaviour

This is the purpose of the grade. Heat resistance is available up to approximately 1150 °C, and good scale resistance in air is maintained up to about 1100 °C, after which performance declines progressively from roughly 900 °C onward as oxide growth accelerates. Compared with the common austenitic grades, the difference is substantial in scale terms: 1.4835 resists oxidation in air to roughly 1100 °C, while 304 and 316 are only oxidation resistant to about 870 °C.

The pressure-vessel position follows the same pattern. Under the ASME code framework, 1.4835 is approved for pressure-retaining service to roughly 900 °C, whereas 304 and 316 are only approved to about 815 °C. For a furnace or heat-treatment installation, that extra temperature headroom is often the difference between a component that survives years of thermal cycling and one that requires premature replacement. The mechanism is worth restating, because it explains the alloy design: nitrogen provides creep strength at temperature, silicon and cerium provide a scale that stays attached during thermal cycling, and chromium provides the reservoir from which the scale is rebuilt after every cooling cycle.

Comparison with 310S and Selection Notes

Grade 310S is the conventional reference point for high-temperature austenitic service, and it is a useful comparison. With its high chromium and nickel content, 310S has excellent resistance to high-temperature oxidation and is a well-proven material. Grade 1.4835 differs in two ways. First, its micro-alloyed composition gives it higher creep strength, so it deforms less under load at temperature. Second, it resists thermal cycling far better, because the cerium- and silicon-rich scale survives repeated heating and cooling without spalling. Where a component is exposed to frequent thermal excursions, sulphur-bearing combustion gases or cyclic loading, 1.4835 is the stronger choice; where the duty is steady and moderate, 310S remains a sound and economic selection.

The limitations should also be stated plainly. Grade 1.4835 is not a seawater or chloride material, and its general aqueous corrosion resistance is lower than that of molybdenum-bearing grades. It is also unsuitable for forging. Within those boundaries it is the standard answer for industrial furnace structures, radiant tubes, heat-exchanger elements, burner components, and high-temperature conveyance equipment that must keep its shape and its oxide scale through many heating cycles.

Frequently Asked Questions

Q: What is 1.4835 equivalent to?
Grade 1.4835 is X9CrNiSiNCe21-11-2 in the EN system and UNS S30815 in the American system, a heat-resistant austenitic stainless steel commonly supplied under its well-known commercial heat-resistant designation.

Q: Is 1.4835 stainless steel magnetic?
It is non-magnetic in the annealed condition. Welded or cold-worked areas may show slight magnetism, which is normal for an austenitic grade.

Q: What is the maximum service temperature of 1.4835?
Heat resistance extends to approximately 1150 °C, while good scale resistance in air is maintained to about 1100 °C and declines gradually from roughly 900 °C upward.

Q: How does 1.4835 compare with 310S?
1.4835 offers higher creep strength and much better resistance to cyclic oxidation spalling thanks to its cerium, silicon and nitrogen additions. Grade 310S remains a solid, economical choice for steady moderate-temperature duty.

Q: Why does 1.4835 contain cerium and silicon?
Both elements improve the adhesion and density of the protective oxide scale, which is what allows the alloy to survive repeated heating and cooling without spalling.

Q: Can 1.4835 be used in seawater or chloride service?
No. The grade has no molybdenum and its aqueous corrosion resistance is lower than that of conventional molybdenum-bearing austenitic grades, so it should not be selected for chloride-bearing wet service.