Study On The Microstructures And Properties Of Slot Wedge Copper Alloys Used In Ultra Supercritical Generator Rotor

This paper investigated the microstructures and properties of slot wedge copper alloys used in ultra supercritical generator rotor. The composition of this kind of copper alloys was rich in natural resources,low cost,no environmental pollution. This paper optimized the combination of the composition, the technology of cast,forge,deformation,heat treatment. Using hardness measurement, tensile test at room, electrical resistance test, metallographic microscope, optical microscopy, SEM, XRD, the mechanical and physical properties and microstructure of slot wedge copper alloys at different elements,processing technique and heat treatment were studied. This paper analyzed the relationship among composition,organization and performance; studied the influence of composition,processing technique and heat treatment on the mechanical and physical properties and microstructure.The research suggests that: This paper adding microelements include: Ni,Cr,Be,Zr,Si,Co. It takes full advantage theirs cross correlation.The optimal process of slot wedge copper alloy is forging, quench, cold deformation, and aging. By the respective best heat treatment, three series of copper alloy can reach following these performances: CuNiCrBeZrSi alloy system: 11# alloy's mechanical and electrical performance can reach: HB≥249, e≥43.45%IACS,σb≥978MPa,σ0.2≥937MPa,δ5≥14.84%, by heat treatment: 960℃×1.5h(solid solution)+30%(cold deformation)+480℃×3.5h(aging). CuNiCoCrBeZr alloy system: 21#,22#,23# alloy's average mechanical and electrical performance can reach: HB≥255, e≥55.92%IACS,σb≥932MPa,σ0.2≥879MPa,δ5≥16.27%, by respective heat treatment: 940℃×1.5h+40%+490℃×3.5h; 950℃×1.5h+30%+490℃×3h; respective, 940℃×1.5h+30%+490℃×3h. CuNiCrBeSiZr alloy system: 21#,22#,23# alloy's average mechanical and electrical performance can reach: HB≥246, e≥31.90%IACS,σb≥864MPa,σ0.2≥816MPa,δ5≥14.72%, by respective heat treatment: 960℃×1.5h+40%+480℃×3h; 950℃×1.5h+30%+480℃×3.5h; respective, 950℃×1.5h+30%+480℃×3.5h.Cold deformation treatment can increase strength greatly. CuNiCoCrBeZr alloy system's combination property is best and satisfies the technical requirement of ultra supercritical generator rotor slot wedge. The content Co of CuNiCoCrBeZr alloy system is 0.5～0.9%, which is equal to 1/5~1/3 of CuCo2BeZr alloy. And the content Be of CuNiCoCrBeZr alloy system is 0.25～0.5%, which is far lower than CuCo2BeZr alloy. This alloy reduce cost,environment pollution,so it has well economic effects.