Stainless Steel Bar

A martensitic stainless steel. It's composed of these major alloy elements (I don't list the minor elements since they don't play a major role) :

Carbon: 1.00-1.25% This increases hardenability and wear resistance, but decreases toughness in higher amounts.

Manganese: .45% This is added to reduce brittleness and improve forgeability, hardenability, and reducing deformation.

Silicon: .30% This is a deoxidizer and improves hot-forming properties.

Chromium: 17.00-18.00% Added only to high alloy tool steels, this improves hardenability, high wear resistance, toughness, and corrosion resistance.

Molybdenum: .50% Improves deep hardening and toughness.

These basic elements (along with iron) are a simple combination that works well together, and has for many decades.