''Tamahagane'' (玉鋼) is a type of

steel Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistant ty ...

made in the Japanese tradition. The word ''tama'' means "precious". The word ''hagane'' means "steel". Tamahagane is used to make Japanese

sword A sword is an edged, bladed weapon intended for manual cutting or thrusting. Its blade, longer than a knife or dagger, is attached to a hilt and can be straight or curved. A thrusting sword tends to have a straighter blade with a pointed ti ...

knives A knife ( : knives; from Old Norse 'knife, dirk') is a tool or weapon with a cutting edge or blade, usually attached to a handle or hilt. One of the earliest tools used by humanity, knives appeared at least 2.5 million years ago, as evidenced ...

, and other kinds of tools. The carbon content of the majority of analyzed Japanese swords historically lies between 0.5–0.7 mass%; however, the range extends up to 1.5%.

Production

Tamahagane is made of an

iron sand Ironsand, also known as iron-sand or iron sand, is a type of sand with heavy concentrations of iron. It is typically dark grey or blackish in colour. It is composed mainly of magnetite, Fe3O4, and also contains small amounts of titanium, silic ...

(''satetsu'') found in Shimane, Japan. There are two main types of iron sands: ''akame satetsu'' (赤目砂鉄) and ''masa satetsu'' (真砂砂鉄). Akame is lower quality, masa is better quality. The 'murage' decides the amount of the mixing parts. Depending on the desired result, the murage mixes one or more types of sands. The iron sand is put in a tatara, a clay tub

furnace A furnace is a structure in which heat is produced with the help of combustion. Furnace may also refer to: Appliances Buildings * Furnace (central heating): a furnace , or a heater or boiler , used to generate heat for buildings * Boiler, used t ...

. The clay tub measures about tall, long and {{convert, 4, ft, m wide. The tub is dried and heated to about 1,000 ° C (1800 ° F). Then, it is mixed with

charcoal Charcoal is a lightweight black carbon residue produced by strongly heating wood (or other animal and plant materials) in minimal oxygen to remove all water and volatile constituents. In the traditional version of this pyrolysis process, cal ...

to add carbon to the steel so it can be hardened. The process of making tamahagane continues for 36-72 hours (a day and a half to three days), depending on how many people work and how much metal is to be obtained. Within an hour of smelting, the iron sand sinks to the bottom, called the bed of fire, in which it will be assessed by color on whether it became Tamahagane. The iron sand is added every ten minutes, and the mixture is frequently turned over. After the tamahagane is finished, the clay tub is broken and the steel is removed. The best steel is on the edges of metal block; in this area, the

oxidation Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a d ...

process is stronger. The quality of tamahagane is determined by its color: bright silver pieces are very good for making blades.

References

Steels Japanese swords

Production

See also

References