退火时间对高强度IF钢组织和性能的影响
杨吉春，杜海龙，王学勇
（内蒙古科技大学材料与冶金学院，内蒙古包头市014010）
关键词：高强度IF钢；显微组织；力学性能；退火时间
中图分类号：TG142.13 文献编码：A
摘要：采用真空感应炉冶炼钢种，盐浴退火方法来模拟连续退火试验，对不同退火时间（10~70 min）试样用万能拉伸试验机、激光共聚焦、扫描电镜来测试试样钢的组织和力学性能。结果表明：随着退火时间的延长高强度IF钢的抗拉强度和屈服强度呈现下降并逐渐趋缓，塑性呈现先升高后降低的趋势，当退火时间为50 min时，材料获得良好的综合力学性能。对试验钢进行组织观察发现不同退火时间下得到的组织均为为细小的铁素体，随着退火时间的延长晶粒大小变化不大，但退火时间为50 min的试样组织更为均匀。利用扫描电镜和能谱分析仪观察试样钢中夹杂物主要为氧化铝和稀土的氧硫复杂化合物。
Influence ofannealing time on the organization and performance of high strength IF steel
YANG Ji-chun, DU Hai-long, WANG Xue-yong
（Materials and Metallurgy School,Inner Mongolia University of Science and Technology, Baotou014010, China）
Key words: high strength IF steel;microscopic structure; mechanical property;annealing time
Abstract: The steel was smelted through vacuuminduction furnace and continuous annealing tests were simulated by salt bathannealing method. Organization and performance of the test steel treated bydifferent annealing time (10-70 min) was measured by means of universal tensiletesting machine, laser confocal microscopy and scanning electron microscope.The results show that with the increase of annealing time, tensile strength andyield strength of high IF steel decreased and the trend gradually slowed down.Meanwhile, plasticity has the trend of increasing first ,and then decreased.When annealing time is 50 minutes, the material can have a favourable comprehensivemechanical property. Fine and small ferrites were found in all theorganizations that were treated under different annealing time by observationof test steel’s organizations. With the increase of annealing time, grain sizedoesn’t change a lot, but the test organization treated through 50 minutes hasa more uniformed structure. Through the observation of the inclusions in thesteel by scanning electron microscopy and energy spectrum analyzer, the maininclusions are aluminium oxides and oxygen and sulfur complex compoundscontaining rare earth elements.