TY - JOUR T1 - The effect of heat input on the microstructure and hardness of continuous fiber laser welded high Al-content δ-TRIP steel TT - اثر حرارت ورودی بر ریزساختار و سختی فولاد δ-TRIP با آلومینیوم بالا در جوشکاری لیزر فیبری JF - JWSTI JO - JWSTI VL - 2 IS - 1 UR - http://jwsti.iut.ac.ir/article-1-77-en.html Y1 - 2016 SP - 69 EP - 76 KW - δ-TRIP steel KW - Heat treatment KW - Fiber laser welding KW - Heat input KW - High Aluminum KW - Micro hardness N2 - Recent research suggests that extraordinary combinations of strength and ductility can be achieved in the so-called TRIP steels. With the development of these steels, welding with small weld nugget size and acceptable strength are needed. For these reasons present study was carried out to investigate the effect of heat input onweld size, microstructure and the hardness of the welded metal of 0.4%C- 4%Al δ-TRIP steel after continues fiber-laser welding process. To achieve this goal a bead on plate welding with three different values of heat input 28, 60 and 80 J/mm were used.The results of welding process revealed that by increasing the heat input, cooling rate decreased and the volume percent of the δ-ferrite in weld metal increased due to the availability of sufficient time for partitioning of Al in high heat input which leads to the stable δ-ferrite and as a result the difference between the hardness of the weld metal in comparison to the base metal decreased. M3 ER -