简介：Themicrostructuresaftercastingandextruding,themechanicalpropertiesandelectricalconductivityafterRRAtreatmentofconventionalDCcastingandlowfrequencyelectromagneticcasting(LFEC)7075aluminumalloywereinvestigated.TheresultsshowedthatfinergrainswhichdistributedmorehomogeneouslywasobtainedinLFECingotscomparedwiththoseconventionalDCingots.TheextrudedbarsofLFECalloykeptitsfinegrainfeaturesoforiginalas-caststructure.IntheRRAtreatment,withtheextensionofsecondagingtime,thetensilestrengthandhardnessofalloydecreased,buttheelectricalconductivityincreased.Meanwhile,asthesecondagingtemperatureraised,thephasechangerateinprecipitationalsoincreased.Underthesameconditions,extrudedbarsofLFECalloyhadbetterperformancethanthatofconventionalDCcastalloy.TheoptimumRRAheattreatmentprocesswas120℃/24h+180℃/30min+120℃/24h.TheLFECextrudedbarsacquiredtensilestrength676.64MPa,hardness198.18,andelectricalconductivity35.7%IACSrespectively,whichwerehigherthanthatintheT6temper,indicatingthatanotableRRAresponsetakesplaceinLFECextrudedbars,whosesecond-stepretrogressiontimewas30min,anditwassuitableformassproduction.

简介：摘要：本文就SEBIM安全阀充水排气方案进行讨论，通过对比分析充水排气工作内容，对RRA、RCV系统SEBIM阀控制柜放射性高的问题进行分析，已降低控制柜内放射性为目的，对目前充水排气方案提出合理的优化改进方案，并应用与现场，且实践效果良好。

简介：摘要：CPR机组在大修期间会进行应急柴油机的检修，通常会在机组下行的NS/RRA模式进行再鉴定工作，近些年柴油机多发运动部件的磨损缺陷，处理后一般要在再鉴定窗口进行磨合试验。随着近些年下行操作的加快及氧化净化时间的缩短，NS/RRA模式窗口渐短，柴油机磨合与高低压贯穿件试验之间窗口重叠，产生冲突，本文主要对磨合试验和高低压贯穿件试验进行分析，得出最优的试验逻辑安排。