1.4742 | X10CrAlSi18 / X10CrAl18 | X17AL

This alloy is available from stock.

Please send enquiries to:

• phone: +49 (2133) 2706-0
• email: [email protected]

• Round EN 10060 / EN 10278
• Flat EN 10058 / EN 10278
• Square EN 10059 / EN 10278
• Hexagonal EN 10278
• Angle EN 10056
• Bar steel, bright steel, wire, wire rod, billets, ingots, semi-finished products

X17AL is a ferritic 17% chromium and aluminum grade with good resistance to high temperature scaling.

X17AL is used where a combination of resistance to scaling and moderate resistance to sulphur and carburizing gases is required. It is used in industrial furnaces, furnace systems, heat exchangers, heat-resistant pipes and high-temperature equipment.

X17AL has both good scale resistance up to 950-1000°C and good resistance to sulphur gases, but very poor resistance in nitriding environments. It should be noted this grade is a heat-resistant steel that used at high temperatures. Therefore, the surface must be free of impurities before use in order to good corrosion resistance at such temperatures. In addition, this grade suffers from embrittlement soaked or slowly cooled at temperatures between 410 and 560°C, and sigma phase at 650-800°C.

This grade is suitable for cold forming as it essentially corresponds to grade X17L.

X17AL has a typical machinability for all non-micro-resulphated ferritic materials. The increase in productivity on the types of machines used, the type of tools used and their geometry, the cutting materials and the type of machining of the parts produced. Its structure influences the surface finish (roughness) and chip morphology. Within certain limits, a slightly harder microstructure, as typical for annealing and cold finishing (e.g. cold drawing), advantages in some machining processes and better surface roughness.

It should be noted that this grade, like any type of ferritic steel, produces large grain structures in the fusion zone and heat affected zone caused by high welding temperatures with a certain risk of embrittlement at room temperature. In certain situations, preheating might be required, while stress relieving should be applied in case of risk of low ductility in the weld metal or in case excessive cold working of the components. In order to avoid a decrease in the ductility of the weld and a loss of aluminum in the weld metal, shielding gases such as hydrogen and nitrogen must not be used. Argon and helium are the preferred choice. In any case, low heat input processes should be used and maintained in all welding processes. Austenitic filler metals should be avoided in sulfurous or carburizing high temperature environments. Ferritic filler metals are the correct choice.

X17AL has good hot formability over a wide range of forging temperatures. Overheating and prolonged soaking should be avoided as this can lead to grain growth. The final steps of forging must be carried out at a lower temperature range with a suitable reduction in to obtain a microstructure with fine and uniform grains. For large blooms and formats, suitable preheating to avoid cracks and air cooling after forging may be necessary. Overheating must always be avoided to reduce the risk of internal chipping and a microstructure with large coarse grains. Annealing after forging should always be carried out to achieve both better corrosion resistance and higher ductility.

1.4742 | X10CrAlSi18 / X10CrAl18 | X17AL