The answer is that cast iron is strong in compression, but weak in tension. ... Steel is strong in compression and tension, and is ductile, not brittle. Stainless steel is usually chosen for corrosive environnments, including salt water

Introduction
Steel is a widely preferred material for making doors despite both iron and steel being susceptible to oxidation. The reasons for this preference lie in the properties and benefits of steel as an alloy.
Corrosion Resistance
- Steel is often treated or coated with materials that enhance its resistance to oxidation, such as galvanization (zinc coating) or painting.
- Stainless steel, a type of steel alloy, contains chromium, which forms a protective layer that prevents rust.
Strength and Durability
- Steel has a higher tensile strength compared to pure iron, making it more robust and capable of withstanding greater forces and impacts.
- It has better structural integrity, ensuring that doors made from steel can last longer without warping or bending.
Fabrication and Aesthetics
- Steel can be easily fabricated into various shapes and designs, allowing for more aesthetic options in door manufacturing.
- It can be molded, cut, and welded, offering versatility in design that pure iron lacks.
Cost-Effectiveness
- Steel is often more cost-effective than iron in terms of lifecycle cost due to its durability and lower maintenance needs.
- Although both materials may oxidize, the longevity of steel doors reduces the frequency of replacements or repairs.
Conclusion
In summary, while both iron and steel can oxidize, steel's enhanced properties such as corrosion resistance, strength, aesthetic versatility, and cost-effectiveness make it the preferred choice for door manufacturing.