热处理对高强大梁钢冲击吸收功的影响分析

为了研究热处理工艺对高强大梁钢冲击性能的影响，采用扫描电镜、透射电镜和EBSD等方法对700L不同热处理工艺后的冲击性能进行了研究。结果显示，热处理工艺对700L的冲击性能影响显著。在低于400 ℃退火时，冲击性能较原板有所提高;在高于550 ℃退火时，钢板组织发生变化，晶界析出大量渗碳体，冲击性能明显恶化。原板经不同奥氏体化温度空冷处理后，850 ℃空冷后的钢板拥有最佳的冲击性能，其组织由等轴的细小铁素体与M/A岛组成。织构分析结果表明，原板拥有较强的{001}〈110〉型织构，这类型织构可能对钢板冲击性能有不利影响，经低温退火处理后，{001}〈110〉型织构强度减弱，经奥氏体化处理后织构消失。

Analysis on effect of heat treatment on impact energy #br# of high strength beam steel

In order to study the effect of heat treatment on the impact energy of high strength beam steels, SEM, TEM and EBSD were used to analyze the impact properties of 700L steels with different heat treatment. Results indicated that heat treatment process had a significant effect on the impact properties of 700L steels. When annealed below 400 ℃, the impact properties of the steel were improved. When annealed above 550 ℃, the microstructure of the steel changed slightly and there were considerable amounts of cementites precipitated along the grain boundary, leading to the deterioration of the impact properties. After air cooling treatment at different austenitizing temperatures, the steel treated at 850 ℃ had the best impact properties, which consisted of fine equiaxed ferrite and M/A islands. Texture results indicated that the original steel obsessed strong texture of {001}〈110〉, which might be unfavorable to the impact properties. After mild temperature annealing treatment, the strength of {001}〈110〉 texture weakened, while after austenitizing treatment, the texture disappeared.