加热工艺对高强耐候钢Cu析出和裂纹的影响

Effect of heating process on Cu precipitation and cracking of high-strength weather-resistant steel

采用光学显微镜(OM)、透射电镜(TEM)等技术研究了热轧加热工艺对高强耐候钢的Cu析出和裂纹的影响,结果表明:通过奥氏体化温度的升高和保温时间的延长使得Cu析出物尺寸和析出量显著减小,因此在实际生产中应需要快速加热至1200℃以上温度并较长时间保温,避免在1083~1200℃温度范围内长时间停留导致裂纹的产生。另外板坯在750℃的热送热装温度进行70%大变形时出现裂纹,因此,为了减少轧制过程中产生裂纹,此钢种应该避开两相区温度进行热送热装及大变形。

The effect of hot rolling process on Cu precipitation and cracking of high-strength weather-resistant steel was investigated by optical microscope(OM)and transmission electron microscope(TEM).The results showed that the size and quantity of Cu precipitates could be significantly reduced by increasing the austenitizing temperature and extending the holding time.Therefore,the temperature should be rapidly increased above 1200℃and kept for long time in practice production.The staying in range of 1083-1200℃should be avoided to prevent the formation of cracking.Furthermore,the cracks on slab were observed during hot transferring and hot charging at 750℃for 70%large deformation.Therefore,in order to reduce the cracking in rolling process,such steel should be kept away from the hot transferring and hot charging at two-phase region temperature as well as large deformation.