The choice of metal for making a sword depends on various factors, including the desired characteristics, intended use of the sword, and the craftsmanship involved. There is no single "strongest" metal for sword making, as different metals have their own strengths and properties. However, some metals commonly used in sword making that are known for their strength and durability include:

1. High Carbon Steel: High carbon steel, especially those with a higher carbon content, is often favored for sword making due to its strength, hardness, and ability to hold a sharp edge. The carbon content provides increased strength and resistance to deformation or breaking. Different types of high carbon steel, such as 1060, 1095, or various tool steels, are commonly used in sword production.
2. Spring Steel: Spring steel, also known as alloy steel, is used for its excellent durability and flexibility. It can withstand bending and return to its original shape, making it suitable for blades that require resilience and resistance to deformation. The addition of alloys like chromium, vanadium, or silicon further enhances its strength and toughness.
3. Damascus Steel: Damascus steel, known for its distinctive patterns and historical significance, is not a specific type of metal but a technique of forging blades. Historically, it was made using a combination of different types of iron or steel, layering and folding them together. This resulted in a blade with a high level of strength, flexibility, and sharpness.
4. Tungsten Carbide: While less common in traditional sword making, tungsten carbide is a modern material that exhibits exceptional hardness and wear resistance. It is often used for industrial cutting tools. Blades made from tungsten carbide can have exceptional durability and edge retention properties.

These are just a few examples of metals commonly used in sword making. The specific type of metal and the quality of its craftsmanship play significant roles in determining the overall strength, durability, and performance of a sword. Skilled swordsmiths and blade manufacturers carefully select the appropriate metal based on the desired characteristics and specific requirements of the sword.