MECHANICAL PROPERTIES OF HEAT-AFFECTED ZONE OF HIGH-STRENGTH STEEL WELDS

摘要

Mechanical properties testing of structural steel welds are well known and standardized. Results of those testing are important information regarding evaluation and qualification of welding technologies. However, using only standardized testing it is not possible to evaluate the weakest part of welds; e.g. coarse-grained heat affected zone, where peak temperature over 1300 °C is reached during fusion welding. Such high temperatures have for consequence significant change and drop of some mechanical properties. Thus, it is important to perform some more sophisticated evaluation and prior preparation of test specimens. Actually, such prior preparation include welding thermo-cycle simulation on test specimen ready for standardized testing. The paper present one combination of testing results, both standardised and sophisticated, for the purpose of more detailed review of mechanical properties of high-strength steel welds with nominal yield strength in the range of 690-890 MPa. Detailed distribution across welds is presented including the following generalised mechanical properties: hardness, strength, toughness. Significant drop of some mechanical properties is observed within coarse-grained heat affected zone, which may require particular attention within everyday engineering practice.