The Forging Process in Steel Bladesmithing
Blade-making is a skill that is part of the blacksmithing tradition that takes raw metal and works it with various techniques to shape it into useful objects. Forged blades must be both hard and flexible to withstand impact yet provide force. The forging process for steel blade-making requires a number of steps that help imbue the metal with both qualities for optimum functionality. Does this Spark an idea?
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Material
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Essentially, forging a knife blade is reshaping a piece of metal into a different form. You must use the best quality of steel for the purpose. Metals come in many designations that indicate the components that make up the steel, such as carbon content and type of alloy mixed with the steel, such as manganese, chromium, nickel or selenium. These components affect the hardness, weldability, flexibility and many other qualities of the steel. The type of steel numbered as 5160 is a good steel for bladesmithing, as well as 01, 1095, 1084 steel and L6, according to the CustomKnife site. The steel is purchased In 35 or 45 mm bar form and flattened in layers into a blade shape.
Forging
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The bar is first heated to a high temperature in a forge. The edges are ground clean and heated and hammered together using borax as flux material, according to the Ferris
Forge site. As steel is heated, it changes colors. These colors indicate the temperature the metal has reached. A cherry red color is used to forge steel for blade-making.
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Quenching
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As the layers are added the steel is repeatedly "quenched" or dipped in tempering oil to quickly cool it, which hardens the steel surface.
Hammering
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The layers of steel are heated and hammered together to create a weld between the layers. The sharp edge is formed with a light hammer. The repeated cycles of heating, cooling and hammering refines the grain of the blade.
Grinding
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The edge of the blade is ground into a final edge and sharpened. The entire surface of the blade is polished to an even surface for good appearance.
De-Stressing
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De-stressing in an important last step in blade forging. The forging process heated the steel of the blade to different temperatures at different points creating stress points throughout the material. To de-stress the metal, heat it to the dark cherry color and allow it to cool slowly. When it is cool to the touch, heat it again, correcting any warping that has occurred. Finally, two additional pieces of steel are heated to a light cherry color. The forged blade is heated one more time and placed between the two pieces of steel, wrapped in an insulating blanket and allowed to cool slowly for 17 to 18 hours. This process is called annealing and prepares the blade for final quenching.
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References
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