Effects of alloying elements on tool steel propertie.

Carbon: Raising carbon content increases hardness slightly and wear resistance considerably.
Manganese: Small amounts of of Manganense reduce brittleness and improve forgeability. Larger amounts of manganese improve hardenability, permit oil quenching, and reduce quenching deformation.
Silicon: Improves strength, toughness, and shock resistance.
Tungsten: Improves “hot hardness” – used in high-speed tool steel.
Vanadium: Refines carbide structure and improves forgeability, also improving hardness and wear resistance.
Molybdenum: Improves deep hardening, toughness, and in larger amounts, “hot hardness”. Used in high speed tool steel because it’s cheaper than tungsten.
Chromium: Improves hardenability, wear resistance and toughness.
Nickel: Improves toughness and wear resistance to a lesser degree.

Pearlite.

Pearlite is a two-phased, lamellar (or layered) structure composed of alternating layers of alpha-ferrite (88 wt%) and cementite (12 wt%) that occurs in some steels and cast irons.

Steels with pearlitic (eutectoid composition) or near-pearlitic microstructure (near-eutectoid composition) can be drawn into thin wires. Such wires, often bundled into ropes, are commercially used as piano wires, ropes for suspension bridges, and as steel cord for tire reinforcement.