正火温度对铁素体珠光体型高强钢力学性能的影响

Effect of Normalizing Temperature on Mechanical Properties of Ferrite/Perlite High Strength Steel

根据实验钢的相变点，设计了系列正火温度试验，得到了正火温度对钢板力学性能影响的规律，并从组织形貌和奥氏体形核机理方面进行了解释。结果表明，随正火温度升高，强度随之降低；正火温度≤890℃，-30℃冲击功为170-180J；正火温度910℃时，-30℃冲击功降至120J。从显微组织看，晶粒尺寸随正火温度的升高而增大；在两相区正火，组织中未出现带状组织，且部分铁素体＋珠光体保持一定位向，与奥氏体化过程中残留的细小铁素体晶粒和形成针状奥氏体有关。

According to the phase transition temperature of test steel, the experiment of normalizing temperatures on the test steel was designed. And the effects of normalizing temperature on mechanical properties were gained which was interpreted from the microstmcture and the theory of austenite nucleation. The results show that with the increase of normalizing temperature, the strength of test steel decreases. The toughness of test steel remains almost unchanged with the normalizing temperatures being lower than 890 ℃. The toughness decreases with the increase of normalizing temperature. As viewed from the microstmcture of sample, the grain coarsens with the increase of normalizing temperature. Ferrite/Pearlite banded structure is not found and some ferrite and pearlite keeps the certain orientation, which is due to the residual fine ferrite grain and acicular austenite.