• nl
  • Several types of steel can be sensitive to brittle breakage at low temperatures.

    In order to be able to indicate the toughness (being the opposite of brittleness) of a steel grade, the impact value of the material is measured at different temperatures.

    When determining the toughness, a notch impact test is done (according to NEN-EN-ISO 148-1). To do this, a normalised test piece fitted with a notch is broken with a drop hammer in a pendulum. The energy required for this can be read/calculated. The impact value is expressed in Joules (Nm), measured at standardised temperatures of 20°C, 0°C, -20 °C, -40 °C, and -60 °C.

    An example: Structural steel S355 J2+N
    The normalised designation 'J2' indicates that the impact value of this material is 27 Joules at a temperature of -20 °C. (+N idicates that the matarial is normalized).