True Combat Value of Wootz

[tsubame1]

Originally Posted by Ann Feuerbach

Not only would phosphorus have made the ingot “hot short” (see above), it would have made the finished product “cold short” (brittle when cold) and this property was noticed in the past. In fourteenth century Moorish Spain, Aly ben ’Abderrahman Ibn Hodeil observed that “… the Hindy sabre often breaks when the weather is cold and shows itself better when the weather is warm” (Bronson, 1986 from Mercier, 1924, 231). This is probably due to the presence of phosphorus in the steel. Hindi sabres derived from Sri Lanka (see above), and indeed Wayman and Juleff (1999, 36) identified steadite, the iron-phosphorous compound, in a crucible ingot from there, suggesting that blades produced in Sri Lanka contained phosphorus. Blades that contain phosphorus in percentages over c. 0.3% can be “cold short” and those that work well and be malleable in the summer can shatter during a cold spell (Rostoker and Bronson, 1990, 22; Percy, 1864, 64).

Hi Ann.

I would like to confirm this quote. Japaneses found the same problems in Manchuria and Siberia. Lesser blades (many officers used family ones, but not the best anyway, and most were made with too much impurities i.e.
phosphorus that's likely the most dangerous of all) went broken so easy to made a concern to Japanese Imperial Army.

The problem was resolved by Seijuro Masahide Aoyama and Mitsutaro Honda from Tohoku University,helped by Toyo-Hamono Co.,Ltd of Sendai
They made a blade in Marugitae, water-quenched. Such blades were called Kikento.The steel was called Tahado-tetsu (nickel-crhome-manganese) from Toyo Hamono Co., Ltd. This is only in the '30s, so I wonder if before it wasn't such an issue the cold or simply there was not the technology to build -40° C resistant blades.

Sources : Ohmura.