Charpy Impact Testing

The Charpy Impact test is a method used to assess the impact toughness of metals and alloys. This test is commonly employed to evaluate the susceptibility of materials to sudden impact and measures the energy absorbed. This test is particularly used in industries such as oil and gas, construction and automotive where the strength and durability of machinery and equipment are critical.

 

Shear and Lateral Expansion

  • Shear: Percent shear in a charpy impact test is a measurement of the amount of brittle and ductile fracture in a broken specimen’s fracture face.
  • Lateral Expansion: Lateral expansion is a measure of the ductility of the material. It refers to the increase in width of the specimen at the point of impact. High lateral expansion values indicate that the material undergoes significant plastic deformation before fracturing, which is a sign of good toughness.

Industry Applications:

  • Construction: Ensures that building materials can withstand sudden impacts and stresses.
  • Oil & Gas: Essential for ensuring the integrity of fasteners in the Oil & Gas sector, where extreme conditions are met.
  • Ministry of Defence: Ensures that all components meet stringent impact requirements providing the military with the capabilities necessary.
  • Automotive: Evaluates the toughness of metals used in vehicles to ensure safety and reliability.
  • Machinery: Assesses the durability of components subjected to dynamic loading conditions.

Standards:

  • Charpy Impact testing is carried out according to various standards, ensuring consistency and reliability of results. The testing temperatures range from -196°C up to ambient temperatures. The relevant standards include:
    • BS EN ISO 148-1
    • ASTM A370
    • ASTM E23

    By adhering to these standards, the Charpy Impact test helps determine if steels, stainless steel, and related alloys meet the specified mechanical properties and identify any production issues that need to be addressed.