Ti微合金化700MPa级高强钢性能均匀性研究

Research on the performance uniformity of 700 MPa grade Ti-microalloying high strength steel

对Ti微合金化700MPa级高强钢钢卷头、中、尾部力学性能、金相组织及析出物进行了研究。结果表明:钢卷头、中、尾部力学性能波动的主要原因是钢卷内外圈析出强化效果不同而导致的。为此,在生产薄规格Ti微合金化700 MPa级高强钢时,采用U形冷却工艺,将钢卷最内圈15m内的带钢卷取温度提高15~20℃,将最外圈15m内的带钢卷取温度提高10~15℃,可使钢卷最内圈强度提高约40MPa,钢卷最外圈强度提高约20MPa,有效改善了带钢通卷性能均匀性,提高了通卷性能合格率。

The mechanical properties, microstructure and precipitates of the head, middle and tail of 700 MPa grade Ti microallogying high strength steel coil were studied. The results showed that the main reason of mechanical properties fluctuation in the head,middle and tail of coil was the difference of precipitation strengthening. So, the U-shaped cooling process was used in the production of thin gauge 700 MPa grade Ti microalloyed high strength steel, the temperature was increased 15-20℃ within 15 meters of the inner coil and the temperature increased 10-15℃ within 15 meters of the outer coil. The tensile strength of the in- aer coil was increased about 40 MPa and the tensile strength of the outer coil increased about 20 MPa. The uniformity and the pass rate of mechanical performance of coil was improved effectively.