研究了固溶温度、保温时间对固溶态及固溶+时效态HR3C奥氏体耐热钢显微组织及力学性能的影响。结果表明: 试验钢在1 150~1 200 ℃固溶处理30 min后的晶粒尺寸变化不大, 超过1 200 ℃后晶粒明显长大; 保温时间对晶粒尺寸无明显影响; 随固溶温度的升高和保温时间的延长, 时效后钢中一次析出相的尺寸变小、数量减少; 在700 ℃的时效过程中, M23C6相沿晶界析出, 二次析出的Z相弥散分布在晶内, 尺寸在100 nm以下, 时效时间超过1 000 h后M23C6相明显粗化, Z相的尺寸变化不大, 但数量不断增多, 在长时时效过程中起到显著的析出强化作用; 随初始固溶温度的升高和保温时间的增长, 相对应的长时时效态的高温屈服强度明显提高。

Effects of solid solution temperature and holding time on microstructure and mechanical properties of HR3C austenitic heat resistant steels in solid solution state and in aged state were investigated, respectively. The results show that the grain size changed slightly when solid solution temperature was at 1 150-1 200 ℃, and the grains grew up obviously when solid temperature was above 1 200 ℃. Holding time had a little influence on grain size. With the increase of solid solution temperature and holding time, both size and amount of prime precipitated phases decreased. M23C6 phase precipitated along grain boundaries during the aging at 700 ℃, and grew up with the increase of aging time and coarsened obviously after aging for more than 1 000 h. The fine and dispersed Z phase precipitated in grains and its size was less than 100 nm. With the increase of aging time, the size of Z phase remained unchanged, while its amount increased continuously. The fine and dispersed Z phase played a precipitation strength role in the steel after aged at high temperature for a long time. With the prime solid solution temperature increasing and holding time prolonging, the corresponding elevated temperature yield strength of the aged steel was improved obviously.