三代非能动核电项目SA-508国产大锻件性能不符合项探讨

Research on NCRs of Domestic-Made SA-508 Heavy Forgings for the Third Generation Passive Nuclear Power Plant

三代非能动核电项目RPV和SG用SA-508 Gr.3 C.1和SA-508 Gr.3 Cl.2锻件设计要求严格,制造难度高,在国产化制造过程中出现了诸多的性能不符合项。定量比较了三代非能动核电项目RPV和SG用SA-508锻件的设计要求与ASME规范要求的差异,并统计分析了RPV和SG用SA-508锻件的力学性能实测值。结果表明,RPV用SA-508Gr.3 C.1锻件的不符合项的主要原因是低温韧性不足,SG用SA-508 Gr.3 C.2锻件的不符合项的主要原因是低温韧性、室温和高温抗拉强度。最后研究了RPV和SG用SA-508锻件化学成分和热处理工艺特点,分析了造成国产化大锻件性能不稳定的原因。为克服SA-508大锻件的制造现状与设计要求的矛盾,亟需对大锻件生产工艺进行优化或采用新型的制造工艺进一步提升大型锻件的性能。

SA-508 Gr. 3 Cl. 1 and Cl. 2 forgings for RPV and SG of the third generation passive nuclear power plant possess characters of top-level design requirements and high manufacturing difficulties. During the domestic production progress,a certain number of Non Conformance Report（ NCR） on mechanical properties were submitted. Design requirements and deviations from ASME code about SA-508 Gr. 3 Cl. 1 and Cl. 2 forgings were studied. The quantitative analysis on the mechanical properties of the forgings was carried out. Results show that low fracture toughness accounts for the major parts of NCR for RPV forgings,while both the low fracture toughness and lower tensile strength are the main reasons of NCR for SG forgings. A research on chemical and heat treatment specialties of SA-508 Gr. 3 Cl. 1 and Cl. 2 forgings used for RPV and SG of was also carried out,in which the contributing factors and countermeasures on the quality instability of domestic-made heavy forgings were studied. In order to overcome the conflict between the manufacturing actuality and design requirements,it makes senses to optimize the process or develop a new process to improve the heavy frogings＇ properties.