Sky Castle katana/ninjato dw23

Measurements
length: 40 1/2"
blade: 29 3/4"
blade width: 1 3/16"
grip and pommel: 10 1/2"
guard: 3" x 3"
weight: 3 lbs 1.6 oz

From the world's last collection of Sky Castle swords. The blade is 1075 high carbon spring steel, austempered* for the ultimate in blade strength, springiness, and uniformity of grain structure. Blade will flex to nearly 45% and return to true! Wide tang, polished brass fittings, corded grip. Blackened steel blade shows a bit of shop/storage wear, but is otherwise pristine - no nicks, never used. Folks may be surprised at these sword's inclusion at TherionArms because the guards and pommels are not historically accurate, but the blade temper is so magnificent that we couldn't pass up the opportunity to offer you these sturdy and reliable work horses.

*"Austempering is an isothermal heat treatment that, when applied to ferrous materials, produces a structure that is stronger and tougher than comparable structures produced with conventional heat treatments. Conventional heat treaters heat the parts to "red heat" in a controlled atmosphere and then quench them in a bath of oil or water that is near room temperature. (Maybe even as high as a few hundred degrees Fahrenheit). This produces a crystalline structure known as martensite, a hard, brittle phase. The parts are then tempered in another furnace at 350°F (177c) to 1100°F (593c) to decrease the "brittleness."

Austempering starts the same way. The parts are heated to red heat in a controlled atmosphere (so they don't scale) but then are quenched in a bath of molten salt at 450°F (232c) to 750°F (399c). The quench temperature is above the martensite starting temperature. Therefore, a different structure results - bainite.

During the process of quenching to martensite, the martensite reaction begins immediately. The result is that the outside of the part may already be transformed while the inside is still red hot. It is this non-uniform phase transformation that results in distortion and tiny micro cracks that lower the strength of the steel.

By contrast, the austempering reaction that produces bainite takes place over many minutes or hours. This results in uniform growth and a stronger (less disturbed) microstructure."

Each Sky Castle sword comes with a lifetime replacement guarantee from swordsmith Larry House of Dragon's Watch Forge and Foundry. Mr. House learned to make these incredibly tough swords at Sky Castle and now carries on the tradition of making austempered steel swords and knives.

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