Abstract: The phase transformation and structure of rough rolled slab (36 mm x 1 500 mm) of steel WL510 (/% : 0. 090C, 0. 13Si, 1.45Mn, 0. 005S, 0. 019P, 0. 040Al, 0. 020Ti, 0. 030Nb) during continuous cooling with 1 〜36 ℃/s have been studied by a Thermecmastor-Z thermal mechanical simulator, and the continuous cooling transformation (CCT) curves are measured by thermal dilatometer method. Results show that at low cooling rate 1 ~ 23 °C/s, polygonal ferrite and minor pearlite are mainly formed in test steel WL510； as the cooling rate ≥30 ℃/s, the main structure in test steel is fine acicular ferrite, minor fine pearlite and martensite/austenite islands. With increasing cooling rate, the structure of test steel is finer.

Key words: Steel WL510 for Automobile Beam, CCT Curves, Thermal Dilatometer Method, Structure, Phase Transformation

摘要： 通过Thermecmastor-Z热模拟试验机研究了WL510钢(/%:0.090C、0.13Si、1.45Mn、0.005S、0.019P、0.040Al、0.020Ti、0.030Nb)粗轧后板坯(36 mm×1 500 mm)在1～36℃/s连续冷却条件下的相变和组织的变化,并用热膨胀法测定了试验钢连续冷却转变(CCT)曲线。结果表明,试验钢WL510在1～23℃/s低冷却速度下,主要形成多边形铁素体和少量珠光体;当冷却速度≥30℃/s时,主要组织为细针状铁素体、少量细珠光体和岛状马氏体/奥氏体(M/A)随着冷却速度的增加,试验钢组织明显变细。

关键词: 汽车大梁用钢WL510, CCT曲线, 热膨胀法, 组织, 相变