Compound armour's strength-and-elasticity compromise

Compound armour paired an elastic low-carbon wrought-iron backing that could dissipate energy with a hard but brittle high-carbon steel face. Early attempts to weld the materials, including Italian work, did not produce a satisfactory bond. The two British methods compared were associated with John Brown and Cammell Laird. One poured molten steel onto an iron plate, while the other poured it into a gap between prepared iron and steel plates. Rolling reduced the bonded plate to about half its initial thickness, leaving roughly one third steel face and two thirds iron backing.