【摘要】 对 4 0 0MPa级超级钢试样在不同温度下加热保温 5min ,并分别进行空冷和水冷 ,然后进行组织分析和性能检测。结果表明 :空冷条件下 ,随加热温度的增加 ,晶粒长大严重 ,力学性能明显下降 ;而在 80 0℃时不仅珠光体发生了明显的球化 ,其强度和硬度值下降也最为明显。水冷条件下 ,70 0℃以前 ,其组织和性能与空冷条件下基本相同 ;80 0℃时珠光体不仅没有发生明显的球化 ,而且其强度和硬度值还有所提高 ;90 0℃以后出现明显淬火组织 ,力学性能也明显提高。更多还原

【Abstract】 The specimens of ultrafine grain steel of 400MPa were heated at different temperature for 5 minutes,and then cooled by air and water respectively,and their microstructure and properties were observed and tested.The results show that the grain size of the specimens grows seriously and the mechanical properties drops obviously with increasing the heating temperature under the condition of air cooling,and at 800℃,not only the pearlites of the specimens spheroidize obviously,but also the value of strength and hardness drop to the lowest point.Under the condition of water cooling,the microstructure and mechanical properties are similar to that under the condition of air cooling reheated below 700℃;at 800℃,not only the pearlites of the specimens do not spheroidize obviously,but also the value of strength and hardness increase slightly;if reheated above 900℃,the specimens have quenched microstructure and the value of strength and hardness increase obviously.更多还原