A study on HAZ’s microstructure and grain size of 10CrNi3MoV steel

0　Introduction10CrNi3MoVsteelisakindofquenchedandtemperedsteelwith 5 90MPahighyieldstrength .Duetoitsexcellentweldabilityandimpacttoughness,10CrNi3MoVsteeliswide lyusedinmainpartofshipstructure .However,itswellpropertiesareachievedinvirtueofcontrollingweldingparam eterstrictly .Atthesametime ,owingtoitscoldcrackingsusceptibility ,10CrNi3MoVsteelneedspreheatingweld .Meanwhile,structureandpropertiesofsteelwillbechangedundertheconditionofweldingthermalcycle .Forexample,twinedmartensitehasb…

A study on HAZ’s microstructure and grain size of 10CrNi3MoV steel

This paper deals with microstructure and grain size of HAZ of 590 Mpa high strength shipstructure steel with welding simulator. While t8/5 time is short, 10CrNi3MoV steel’s microstructure of coarse grain heataffected zone (CGHAZ) is lath martensite structure and a small amount of twined martensite structure; while t8/5 time is long, it is mainly granular bainite structure. After second thermal cycle with peak temperature between critical temperature Ac1′and Ac3′, CGHAZ has the inheritance of coarse grain and coarse microstructure. Welding energy input (determined by t8/5 time) has an effect on the inheritance of coarse microstructure, but no influence on the inheritance of coarse grain. In detail, with a shorter t8/5 time, there is an inheritance of coarse microstructure and grains. With a longer t8/5 time, there is only the inheritance of coarse grains. While t8/5 increases, the scope of temperature of causing it diminishes. Therefore, the inheritance of coarse microstructure connects with the high speed of heating and cooling.