Krupp cemented armour (Krupp cemented steel, K.C. armor, or KCA) 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 0.35, silicon 0.07, phosphorus 0.025, sulfur 0.020. KCA still retains the hardened face of Krupp armour via the application of carbonized gases but also retains a much greater fibrous elasticity on the rear of the plate. This increased elasticity greatly reduced the incidence of spalling and cracking while subject to incoming fire, something highly prized during long engagements. Ballistic testing shows that KCA and Krupp armour were roughly equal in other respects.