- Grade / Alloy
- 1.4742
- EN / W.Nr.
- 1.4742X10CrAlSi18 / X10CrAl18
- AISI / SAE
- —
- UNS
- —
- Family
- Ferritic
Chemical composition
Chemical composition
Composition limitsComposition limits for heat-resisting steels within EN 10095.
| Element | Content (% by mass) |
|---|---|
| CCarbon | ≤ 0.12 |
| SiSilicon | 0.7–1.4 |
| MnManganese | ≤ 1 |
| PPhosphorus | ≤ 0.04 |
| SSulfur | ≤ 0.015 |
| CrChromium | 17–19 |
| AlAluminium | 0.7–1.2 |
Values describe the grade, not the analysis of a specific batch. The applicable product specification and material certificate determine acceptance. A dash does not mean zero.
What kind of steel is 1.4742?
1.4742 is a heat-resistant ferritic steel with the chemical designation X10CrAlSi18. Chromium, aluminium and silicon contribute to its resistance to oxidation in hot service. Its structure differs from that of austenitic heat-resistant stainless steels. Its usefulness is therefore not described by chromium and nickel content alone: relatively low thermal expansion and behaviour in hot gases also matter. These characteristics explain its role in furnace and energy equipment.
Surface protection in hot environments
A grid, conveying component or burner element inside a furnace can contact hot gases directly. The protective behaviour of the oxide layer on its surface then becomes important. The alloy balance of 1.4742 is directed towards such hot environments. Ferritic heat-resistant steels have a particular role in some sulfur-bearing gas applications. Lower expansion than austenitic grades during temperature changes is also useful for long components and broad surfaces.
Typical applications
Applications include furnace equipment, hot boiler sections, burner nozzles and hot conveying arrangements. A component may direct a gas stream, separate hot zones or carry a relatively light load. Maximum mechanical strength is not the defining need in every case. A useful role for heat-resistant ferritic steels is in equipment where resistance to hot gases and low expansion are more important than carrying heavy loads at high temperature.
How it differs from 1.4762
1.4742 and 1.4762 belong to the same chromium-aluminium-silicon group but have different compositions. Higher chromium distinguishes 1.4762 and provides a different resistance balance in certain hot-gas environments. Higher chromium does not automatically give a better result in every component, however. Load at temperature and gas conditions help explain their different applications. Grade 446 / 1.4749 has a separate chemical definition again.
Typical application areas
Furnace elements, burner components and hot conveying equipment.
Product and cutting options
Relevant product forms for this material are listed below. Availability varies with grade and dimensions.