High and ultra-high strength steels (S960QL - S1300QL) are already successfully used in some industries, for example in mobile crane construction. In order to ensure that these steels become more widespread, sufficient toughness should be ensured, even in the welded state and at low ambient temperatures. In principle, toughness can be determined by two tests: The notched bar impact test can be used to determine qualitative toughness values, and the fracture mechanics test can be used to obtain quantitative information on the toughness present. However, since fracture mechanics tests are considerably more complex and thus more expensive, one aim of the work is to find a correlation between the results of the notched bar impact test and the fracture mechanics test.
Within the scope of the work, welding seams are first to be welded under guidance with the help of a robot. During the welds, temperatures are measured with thermocouples for process control. Subsequently, the characterization of these welds is carried out by means of notched bar impact and fracture mechanics tests. Both tests are carried out at temperatures below room temperature, so that a tempering with cooled ethanol or liquid nitrogen is carried out. After the test evaluation, a correlation between the two test results is to be found in a further step.
