Krupp armour

Krupp armour was a type of steel armour used in the construction of capital ships starting shortly before the end of the nineteenth century. It was developed by Germany's Krupp Arms Works in 1893 and quickly replaced Harvey armour as the primary method of protecting naval ships.

The initial manufacturing of Krupp armour was very similar to Harveyized armour; however, while the Harvey process generally used nickel-steel, the Krupp process added as much as 1% chromium to the alloy for additional hardness. Also, while Harveyized armour was carburized by heating the steel and placing charcoal on its surface for long periods (often several weeks), Krupp armour went a step further. Instead of inefficiently introducing carbon at the surface with coal, Krupp armour achieved greater depth of carbon cementation by applying carbon-bearing gases to the heated steel. Once the carburization process was complete, the metal was then transformed into face hardened steel by rapidly heating the cemented face, allowing the high heat to penetrate 30% to 40% of the steel's depth, then quickly quenching first the superheated then both sides of the steel with powerful jets of either water or oil.

Krupp armour was swiftly adopted by the world's major navies; ballistic tests showed that 10.2 inches (25.9 cm) of Krupp armour offered the same protection as 12 inches (30.4 cm) of Harvey armour. By the early twentieth century it was in turn rendered obsolete by the development of Krupp cemented armour.

References

• Brown, David K. (2003). Warrior to Dreadnought, warship development 1860-1905. Caxton Publishing Group. ISBN 1-84067-529-2.
• Gene Slover. "Armour chapter XII". Gene Slover's US Navy Pages - Naval Ordnance and Gunnery. Retrieved 28 March 2015.