Krupp armour
Encyclopedia
Krupp armour was a type of steel
armour
used in the construction of capital ship
s starting shortly before the end of the 19th 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
in order to gain additional hardness. Also, while Harveyized armour was carburized
by heating the steel and physically placing charcoal on its surface for long durations (often several weeks), Krupp armour took this basic idea a large step forward. Instead of attempting to inefficiently introduce carbon at the surface from coals, 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 thirty to forty percent of the steel's depth, then quickly quench
ing 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 20th century it was in turn rendered obsolete by the development of Krupp cemented armour
.
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
armour
Armour
Armour or armor is protective covering used to prevent damage from being inflicted to an object, individual or a vehicle through use of direct contact weapons or projectiles, usually during combat, or from damage caused by a potentially dangerous environment or action...
used in the construction of capital ship
Capital ship
The capital ships of a navy are its most important warships; they generally possess the heaviest firepower and armor and are traditionally much larger than other naval vessels...
s starting shortly before the end of the 19th century. It was developed by Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
's Krupp Arms Works in 1893 and quickly replaced Harvey armour
Harvey armor
Harvey armor was a type of steel armor developed in the early 1890s in which the front surfaces of the plates were case hardened. The method for doing this was known as the Harvey process....
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
Chromium
Chromium is a chemical element which has the symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-gray, lustrous, hard metal that takes a high polish and has a high melting point. It is also odorless, tasteless, and malleable...
to the alloy
Alloy
An alloy is a mixture or metallic solid solution composed of two or more elements. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may or may not be homogeneous in distribution, depending on thermal history...
in order to gain additional hardness. Also, while Harveyized armour was carburized
Carburization
Carburizing, spelled carburising in the UK, is a heat treatment process in which iron or steel is heated in the presence of another material which liberates carbon as it decomposes. Depending on the amount of time and temperature, the affected area can vary in carbon content...
by heating the steel and physically placing charcoal on its surface for long durations (often several weeks), Krupp armour took this basic idea a large step forward. Instead of attempting to inefficiently introduce carbon at the surface from coals, Krupp armour achieved greater depth of carbon cementation
Carburization
Carburizing, spelled carburising in the UK, is a heat treatment process in which iron or steel is heated in the presence of another material which liberates carbon as it decomposes. Depending on the amount of time and temperature, the affected area can vary in carbon content...
by applying carbon-bearing gases to the heated steel. Once the carburization process was complete, the metal was then transformed into face hardened steel
Case hardening
Case hardening or surface hardening is the process of hardening the surface of a metal, often a low carbon steel, by infusing elements into the material's surface, forming a thin layer of a harder alloy...
by rapidly heating the cemented face, allowing the high heat to penetrate thirty to forty percent of the steel's depth, then quickly quench
Quench
In materials science, quenching is the rapid cooling of a workpiece to obtain certain material properties. It prevents low-temperature processes, such as phase transformations, from occurring by only providing a narrow window of time in which the reaction is both thermodynamically favorable and...
ing first the superheated
Superheating
In physics, superheating is the phenomenon in which a liquid is heated to a temperature higher than its boiling point, without boiling...
then both sides of the steel with powerful jets of either water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
or oil
Mineral oil
A mineral oil is any of various colorless, odorless, light mixtures of alkanes in the C15 to C40 range from a non-vegetable source, particularly a distillate of petroleum....
.
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 20th century it was in turn rendered obsolete by the development of Krupp cemented armour
Krupp cemented armour
Krupp Cemented Armour is a further evolved variant of Krupp Armour, developed during the early years of the 20th Century. The process is largely the same with slight changes in the alloy composition: in % of total – carbon 0.35, nickel 3.90, chromium 2.00, manganese .35, silicon .07, phosphorus...
.