What are the properties of 1045 carbon steel and why is it used in swords?
Updated Feb 2026
1045 carbon steel is a medium-carbon steel with a carbon content of approximately 0.45 percent, placing it in the middle of the carbon content range used for sword production. The carbon content determines how hard the steel can become through heat treatment: higher carbon means the potential for greater hardness, but also greater brittleness if the tempering is not managed correctly. At 0.45 percent, 1045 achieves functional hardness through quenching and tempering while retaining significant toughness - the material can flex and absorb force without cracking. This combination of moderate hardness and good toughness makes 1045 an appropriate material for a sword that will be handled regularly as a display collectible. It is less hard than T10 or 1095 at the cutting edge, which means it does not hold a fine edge as persistently, but for a display sword that is not being used in cutting practice, this difference is irrelevant. The material's toughness under handling is the more practically significant property, and 1045 performs well in this respect.