Mechanical properties of SMA- and SA-welded joints for quenched and tempered steel STE 470

The report is given of test results on mechanical properties of shielded metal arc and submerged arc welded joints of quenched and tempered steel StE 470. The tests comprise conventional hardness, tensile and Charpy-V testing, as well as fracture mechanics testing. The test results of the welded joints show satisfactory strength, toughness and transition behaviour as compared with the corresponding properties of the base material. The arc energy in the range of 17 kJ/cm to 50 kJ/cm has no marked effect on the mechanical properties of the joints. The Charpy-V-transition temperatures lie in the Orange of -40 °C to -60 °C for the weld metals and -30 °C to -45 °C for the fusion boundaries with all the three arc energies 17, 30 and 50 kJ/cm used. Correspondingly, the Kj-transition behaviour of the joints was found to be almost independent of the arc energy. The SMA-welds showed, however, brittle pop-in behaviour at all K rest temperatures, i.e. -80 °C to +20 °C. The reason suggested for this is the heterogeneity of the SMA-weld metals arising from the weawing technique used in the SMAW-tests.