According to Wikipedia:
"Aluminized steel is steel that has been hot-dip coated on both sides with aluminium-silicon alloy. This process assures a tight metallurgical bond between the steel sheet and its aluminium coating, producing a material with a unique combination of properties possessed neither by steel nor by aluminium alone. Aluminized steel shows a better behavior against corrosion and keeps the properties of the base material steel for temperature lower than 800 °C (1,470 °F). For example, it is commonly used for heat exchangers in residential furnaces, commercial rooftop HVAC units, automotive mufflers, ovens, kitchen ranges, water heaters, fireplaces, barbecue burners, and baking pans. This steel is very useful for heating things up because it transfers heat faster than most other steels."