Impact energy
Impact energy is the work that a hammer uses to break through a specimen. It measures the material against sudden deformation and fracture.
Physical-Chemical Mechanism of Action
The impact energy is the product of hammer mass and the square of the velocity at impact. It describes how much energy is put into the material.
Metallurgical Relevance & Risks in Welding
High impact energy can cause high pressure, leading to porosity and reduced material strength. If impact energy is too low, workpieces may not deform sufficiently, resulting in incomplete fusion or fracture.
Workshop Practice & Instructions
The optimum impact energy depends on the material and the desired deformation. For steel specimens in the Charpy impact test, typical impact energy is between 10 and 20 joules per kg of material. The hammer velocity should be set so that the specimen is struck in about 3-5 milliseconds.