Harvey armor

The year 1894 would see the ten main producers of armor plate, including Vickers, Armstrong, Krupp, Schneider, Carnegie and Bethlehem Steel, form the Harvey Syndicate.

This process produced a sharp transition between the properties of the two plates in a very small distance.

In this process, the steel plate would be covered with charcoal and heated to approximately 1200 degrees Celsius for two to three weeks.

The process increased the carbon content at the face to around 1 percent; the carbon content decreasing gradually from this level with distance into the plate, reaching the original proportion (approximately 0.1–0.2 percent) at a depth of around an inch.

The process was further improved by low temperature forging of the plate before the final heat treatment.