Spring steel is not traditionally used for crafting Japanese katana swords. While spring steel, known for its elasticity and resilience, has its advantages, it does not possess the same metallurgical properties and characteristics as the steels traditionally used in katana production.

The Japanese katana is traditionally made using Tamahagane steel, which is a type of steel produced through a specific smelting process in Japan. Tamahagane steel has a lower carbon content and is known for its combination of hardness, flexibility, and edge retention. These characteristics are crucial for the performance and cutting ability of a katana.

While spring steel can be suitable for other types of blades and applications, using it for a katana may result in a sword that deviates from the traditional performance and aesthetic characteristics associated with a Japanese katana.

If you are considering a sword in the style of a katana but made from spring steel, it may be better categorized as a "katana-inspired" or "katana-like" design rather than a traditional Japanese katana. It is important to consult with experienced swordsmiths or experts who can provide guidance on appropriate steel choices and crafting techniques to achieve the desired performance and characteristics for a specific sword design.