【摘要】 利用φ350mm四/二辊热轧实验机进行Q500qENH钢中试轧制，得到的试验钢板经400～750℃系列温度回火后，进行轧态及回火态性能检测，运用光学显微镜、扫描电子显微镜及透射电镜进行微观物相分析。结果表明：轧态组织高密度的位错使贝氏体、铁素体具有良好的韧性和较高的强度；随回火温度升高，基体组织针状铁素体逐渐多边形化，当650℃回火时铁素体基体上出现细小的Nb(C,N)和ε-Cu粒子，在750℃回火时，Nb(C,N)和ε-Cu颗粒数量减少，尺寸出现粗化；当回火温度在400～500℃时，强度及冲击韧性比TMCP状态稍高，屈强比均低于0.86，回火温度在500～650℃时，韧性和屈强比均明显上升，在回火温度650℃时屈强比达到最大值0.88，回火温度达到700～750℃时，强度开始急剧下降，并且在750℃时，韧性出现明显恶化。更多还原

【Abstract】 The Q500qENH pilot test was carried out by a Φ350 mm four/two roll hot rolling experimental machine.The test steel plate was tempered between 400 and 750℃,and the properties of the rolled and tempered was performed further by using scanning electron microscopy,optical microscopy,and transmission electron microscopy.The results indicate that the bainite ferrite has good toughness and high strength because of the highdensity dislocations in the rolled micro-structure.As the tempering temperature increases,the acicular ferrite in the matrix organization becomes polygonal.When the tempering temperature is 650℃,small Nb(C,N) and ε-Cu particles appear on the acicular ferrite.When the tempering temperature is 750℃,the quantity of Nb(C,N) andε-Cu decreases and their size becomes coarser.When the tempering temperature is between 400 and 500℃,the strength and impact toughness are slightly higher than those of TMCP state,and the yield strength ratio is lower than 0.86.When the tempering temperature is between 500 and 650℃,the toughness and yield strength ratio both increase significantly,and the yield strength ratio reaches the maximum value of 0.88 at the tempering temperature of 650℃.When the tempering temperature is between 700 and 750℃,the strength decreases rapidly,and the toughness deteriorates when tempering temperature reaches 750℃.更多还原