核电站压力容器用锰铬钼镍低碳合金钢大截面锻件断裂韧性研究

FRACTURE TOUGHNESS OF HEAVY SECTION LOW-CARBON Mn-Cr-Ni-Mo ALLOYED STEEL FORGING FOR PRESSURE VESSEL IN NUCLEAR POWER STATION

研究了含锰、铬、钼、镍压力容器用钢的化学成分和热处理条件对断裂韧性（ＫＩＣ）的影响。实验结果表明：对大截面锻件来说，适当增高合金中镍含量的同时，必须改变冷却速度，获得细小板条下贝氏体组织，回火后贝氏体铁素体板条中均匀分布着细小弥散的碳化物，可使ＦＡＴＴ明显移向低温，增加上平台能量，提高断裂韧性。

The effect of chemical composition and heat treatment on the fracture toughness of steel A508-3 (Mn-Cr-Ni-Mo) for pressure vessel was investigated. The experimental results show that when the content of Ni is moderately increased the quench cooling rate of the heavy forging must be changed in order to obtain low bainite with thin plates and tiny dispersive carbide in ferrite plates after tempering thus fracture appearance transition temperature (FATT) can be moved to lower temperature obviously, with increased upper shelf energy and improved fracture.