连退加热温度对热镀锌双相钢DP780组织性能的影响

Effect of Continuous Annealing Heating Temperature on Microstructures and Properties of DP780 Hot-dip Galvanized Dual Phase Steel

对热镀锌DP780进行了不同退火温度的热模拟实验。结果显示,随着退火温度的提高,拉伸强度呈现出先下降后上升的趋势。当退火温度780~800℃时,材料晶粒尺寸长大,造成材料的力学性能下降;在800~820℃退火时,材料马氏体含量增加,使得材料强度得到明显提升;当退火温度继续提升时,原始奥氏体虽然体积分数得到增加,但原始奥氏体中的碳化物和合金元素含量显著下降,造成其淬透性降低。

Thermal simulation experiments with different annealing temperatures for DP780 were carried out.The experimental results showed that the tensile strength demonstrated the trend of decreasing at first and then increasing with rising of annealing temperature.When the annealing temperature was between 780 C and 800 C,the grain size of the steel material grew up,resulting in the deterioration of the mechanical properties of the material.While the annealing temperature was between 800℃and 820℃,the fraction of martensite in the material increased,which made the material strength improved obviously.As the annealing temperature kept on rising,the volume fraction of the original austenite increased,but the content of carbide and alloying elements in the original austenite decreased significantly,resulting in the declining of hardenability.