TY - JOUR A1 - Falkenreck, Thora E. A1 - Kromm, Arne A1 - Böllinghaus, Thomas T1 - Investigation of physically simulated weld HAZ and CCT diagram of HSLA armour steel JF - Welding in the World N2 - The phase transformation under various cooling rates and in different HAZ regions for high-strength armour steel was analysed by dilatometry. To develop a continuous cooling transformation (CCT) diagram, the samples were heated up to a peak temperature of 1250 °C to achieve a coarse-grained microstructure and then cooled down with a cooling time t 8/5 varying from 3 to 240 s. Analysis of dilatation curves revealed the austenite decomposition process, during which transformation temperatures were determined. The results showed martensitic transformations for all welding-relevant cooling times. Furthermore, to analyse different heat-affected subzones of the weld, the peak temperature was varied between 550 and 1250 °C at a constant cooling time t 8/5 of 6 s. The simulated coarse-grained heat-affected zone (CGHAZ) and fine-grained-heat affected zone (FGHAZ) showed only martensitic transformations with transformation temperatures below 400 °C. The steel exhibited an inhomogeneous hardness with hardening in the CGHAZ and FGHAZ and softening in the intercritical and subcritical HAZ. The physically simulated microstructure was validated by a real hybrid laser-arc weld microstructure. KW - Dilatometry KW - High-strength steels KW - CCT diagrams KW - Heat-affected zone PY - 2018 DO - https://doi.org/10.1007/s40194-017-0511-4 SN - 0043-2288 SN - 1878-6669 VL - 62 IS - 1 SP - 47 EP - 54 PB - Springer AN - OPUS4-44716 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -