Definition

1. Noun:
   • A type of steel alloy: "hyper-eutectoid steel" is a specific classification of steel based on its carbon content. It refers to steel that contains more than 0.9% carbon by weight. This carbon percentage places it beyond the eutectoid point on the iron-carbon phase diagram, resulting in a distinct microstructure and material properties compared to steels with lower carbon content.

Usage Examples

• Noun:
  • The bearing was manufactured from hyper-eutectoid steel for its superior hardness and wear resistance.
  • When the carbon content exceeds 0.9%, the resulting alloy is classified as hyper-eutectoid steel.

Advanced Usage

• Technical Specification: The term is primarily used in metallurgy, materials science, and engineering contexts to specify material composition and predict properties like strength, hardness, and machinability.
  • The design called for a hyper-eutectoid steel to ensure the component could withstand extreme abrasive conditions.

Variants and Related Words

• Eutectoid steel (n): Steel with exactly 0.8% carbon, forming a specific microstructure (pearlite) upon slow cooling.
  • Eutectoid steel serves as a reference point on the iron-carbon diagram.
• Hypoeutectoid steel (n): Steel containing less than 0.8% carbon.
  • Mild steels are typically hypoeutectoid steels.

Synonyms

• High-carbon steel (with specification): While "high-carbon steel" is a broader category, it can be synonymous when specifying carbon content above 0.9%. The term "hyper-eutectoid" is more precise within technical discourse.

Related Phrases and Terminology

• Contains proeutectoid cementite: This phrase describes a key microstructural feature of hyper-eutectoid steel, where cementite (iron carbide) forms before the eutectoid transformation.
  • Upon cooling, hyper-eutectoid steel forms proeutectoid cementite at the grain boundaries.

Noun

1. a steel that contains more than 0.9% carbon