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对核电站蒸汽发生器用690合金传热管进行不同保温时间的特殊热处理,研究保温时间对690合金传热管显微组织、拉伸性能和晶间腐蚀性能的影响。研究结果表明:经10~30 h的特殊热处理后,690合金传热管晶界均分布连续或半连续的碳化物,且晶内分布极少量的碳化物和大量的孪晶;随着保温时间的增加,碳化物有粗化的现象,室温及350℃拉伸性能变化不大,拉伸性能缓慢增加,350℃的抗拉强度仍能保持在600 MPa以上;随着特殊热处理保温时间的增加,690合金传热管晶间腐蚀速率未发生明显变化,且均不超过13 mdd(毫克/平方分米·天)。
The special heat treatment of 690 alloy heat transfer tube was carried out for the steam generator of nuclear power plant, and the effect of holding time on the microstructure, tensile property and intergranular corrosion resistance of 690 alloy heat transfer tube was studied. The results show that: after 10 ~ 30 h of special heat treatment, 690 alloy heat transfer tube grain boundaries are distributed continuously or semi-continuous carbides, and the distribution of very small amounts of carbide and a large number of twins; with the holding time , The carbides have roughening phenomenon. The tensile properties at room temperature and 350 ℃ have little change, the tensile properties slowly increase, and the tensile strength at 350 ℃ can still be kept above 600 MPa. With the increase of holding time of special heat treatment The intergranular corrosion rate of the 690 alloy heat transfer tube did not change significantly, and both did not exceed 13 mdd (mg / dm · day).