Overview

1.4818 is a heat-resistant austenitic chromium-nickel stainless steel based on the 18Cr-9Ni (1.4301-type) composition but with increased silicon and nitrogen contents and microalloyed with rare-earth metals (cerium), which together raise its maximum service temperature in dry air to about 1000 °C. This datasheet presents the material within the European standard system.

It is positioned between the standard 1.4301 grade (max ~800 °C) and the more highly-alloyed 1.4835 grade (max ~1150 °C), offering substantially better high-temperature performance than 1.4301 at a lower alloy content and cost than the higher grades. The cerium and silicon improve the stability and adherence of the protective oxide scale, while the nitrogen provides solid-solution strengthening and stabilises the austenite; together they give good oxide stability, resistance to sigma-phase precipitation and good strength at high temperature. The fully austenitic structure also provides excellent toughness down to cryogenic temperatures. Optimum performance is obtained in the range about 600–950 °C, where creep strength is usually the dimensioning factor.

Typical applications include industrial-furnace components, radiant tubes and muffles, heat-treatment fixtures and conveyor parts, automotive exhaust and emission-control components, heat exchangers and recuperators, and other equipment operating at elevated temperature. As with other austenitic grades, resistance is best in oxidizing atmospheres; resistance to oxidizing sulphur-bearing gases is limited.

1. Physical Properties

2. Chemical Composition (wt %)

Composition per EN 10088-2 / EN 10095 (W.Nr. 1.4818, X6CrNiSiNCe19-10).

Nominal: 19Cr-10Ni-Si-N-Ce heat-resistant steel. Silicon, nitrogen and cerium give improved oxidation resistance and creep strength over standard 1.4301-type grades, for service to ~1000 °C.

3. Mechanical Properties

Solution-annealed (+AT) condition, per EN 10088-2 for W.Nr. 1.4818.

Values per EN/DIN; confirm against the inspection certificate (EN 10204).

4. Oxidation and High-Temperature Resistance

5. Heat Treatment

An austenitic stainless steel; it cannot be hardened by heat treatment. Strength is increased only by cold work.

Solution Anneal approximately 1050–1150 °C, followed by rapid cooling (water quench or rapid air), to dissolve carbides and produce a uniform austenitic structure with optimum oxidation and creep behaviour.

Prolonged exposure in the ~600–900 °C range can lead to some embrittlement; ductility can be restored by re-solution-annealing followed by rapid cooling. The cerium and nitrogen additions help resist sigma-phase precipitation.

6. Weldability and Joining

Has good weldability and can be joined by submerged-arc, plasma-arc, flux-cored-arc, shielded-metal-arc, gas-tungsten-arc and gas-metal-arc processes. A matching or over-alloyed heat-resistant filler is used; preheating is not required.

No preheat required. Keep heat input controlled; solution anneal after welding where maximum high-temperature performance is required.

7. Machinability and Fabrication

Machining Guidelines

Forming Processes

8. Applications

9. Available Product Forms and Standards

Heat-resistant Si-N-Ce austenitic stainless steel (19Cr-10Ni). W.Nr. 1.4818 (X6CrNiSiNCe19-10); EN 10095. (Variant of 1.4301 with increased Si, N and rare-earth metals.)

10. Comparison with Related Alloys (Werkstoff-Nummer System)

Next：X6CrNiSiNCe19-10