Abstract: In order to investigate the negative temperature impact properties of 14Cr1MoR steel extra thick plates, the negative temperature impact tests at 0~-30℃,for 136 mm thick 14Cr1MoR steel plates produced by a steel plant with delivery ( normalizing + tempering) and max PWHT state are carrued out,and by metallographic microscope, the full thickness structure, grain size and inclusions in steel with delivery and max PWHT state are analyzed. The results show that the ultimate impact temperature of 14Cr1 MoR steel extra thick plate is -30°C,the -30 °C impact energy at 1/2 plate thickness with delivery and max PWHT state are respectively 150 ~ 173 J and 19. 5 ~ 97 J. The metallographic structure study shows that the main reason that affects the negative temperature impact performance of steel plate after max. PWHT is the carbides aggregate and grow up in the grain and grain boundary, and tend to spheroidize, which weakens the toughness of matrix and the properties of grain boundary, thus resulting in a significant decrease in impact energy.

Key words: 14CrlMoR Steel, 136 mm Plate, Negative Impact Toughness, Carbide ,

摘要： 为探究14Cr1MoR钢特厚板的低温冲击性能,对钢厂生产的136 mm厚14Cr1MoR钢板分别进行了交货状态(正火+回火)和长时模焊后的0～-30℃低温冲击试验,并借助金相显微镜对交货状态下和长时模焊后的全厚度组织、晶粒度和夹杂物进行了统计分析。结果表明:14Cr1MoR钢特厚板的极限冲击温度为-30℃,交货状态和长时模焊板厚1/2处-30℃冲击功分布为150～173 J和19.5～97 J。金相组织研究表明,影响钢板长时模焊后低温冲击性能下降的主要原因为碳化物在晶内和晶界处聚集长大,并趋向于球化,使基体韧性和晶界处性能大为弱化.从而导致冲击功明显下降。