The subject of impact testing continues from last month’s discussion by looking at the Charpy “V” notch test in more detail. Let’s learn more.
Charpy test specimens normally measure 55 mm x 10 mm x 10 mm and have a notch machined across one of the larger faces. The basic types of notches are the “V” notch, keyhole notch and “U” notch (Fig. 1). The V-shaped notch is 2 mm deep, with 45° included angle and 0.25-mm radius at its root. The U-shaped notch is 5 mm deep with vertical sides and a 1-mm radius U-shaped root. The keyhole notch is also 5 mm deep and contains a 2-mm-diameter hole and vertical sides. The notch shape, depth and tip radius are, therefore, important test parameters.