Krupp armour

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.

Instead of inefficiently introducing carbon at the surface with coal, Krupp armour achieved greater depth of carbon cementation by applying carbon-bearing gases (coal gas or acetylene)[2] to the heated steel.

[3] The manufacturing process remained largely the same, with slight changes in the alloy composition: in % of total – carbon 0.35, nickel 3.90, chromium 2.00, manganese 0.35, silicon 0.07, phosphorus 0.025, sulfur 0.020.

This increased elasticity greatly reduced the incidence of spalling and cracking under incoming fire, a valuable quality during long engagements.

Ballistic testing shows that KCA and Krupp armour were roughly equal in other respects.