Lead Frame Cu-fe-p Alloy Rolling And Heat Treatment Process

Cu-Fe-P alloys have taken up a large proportion in the use of lead frames materials due to their good electrical and thermal conductivity and low cost. In this paper, some problems in the process of producing Cu-0.11Fe-0.03P alloys were analyzed by experiments so as to provide some theoretical references for factories. The effects of hot rolling and heat treatment technology on the alloying structures and properties were investigated. Various alloys were produced by changing the parameters, their morphologies and microstructures were characterized by using scanning electron microscopy, metallography microscopy etc., and by means of testing and comparing their properties, the internal laws were discussed. The results are shown as following:1) It is very favorable for mill processing to isothermal treatment prior to hot rolling. The plasticity of alloys were enhanced greatly and the deformation resistance were reduced after isothermal 60min at 850℃-950℃, the shape and quality of rolled alloys surface were, better than those untreated.2) The hot rolling temperature influenced the quality of rolled pieces most. The suitable hot rolling temperature of KFC (Cu-0.11Fe-0.03P) alloys was at 850℃-950 ℃, when the crystal grain size was moderate, the structure was compact and homogeneous as well as flat shape of work pieces, which favored the later treatments.3) Controlling the temperature in the solution treatment was very important. The favorable results could be obtained at 750℃, when the solution elements could dissolve into the substrates sufficiently and the simplex a-solid solution twinned crystal could be easily produced with homogeneous crystal grain size. The properties of alloys after aging treatment were most perfect.4) More than 80% of cold rolling deformation prior to aging treatment would accelerate the solution precipitation obviously and refine the alloys crystal grain greatly.5) The key of aging treatment was to control the volume ratio and grain size ofthe precipitation phase. The effects of aging temperature and time on precipitation counted equally. The optimal alloying micro-hardness and electrical conductivity could be reached 135HV and 95% respectively when they were aged at 520°C for 4.5 hours.6) Softening temperature of KFC alloy related to deformation degree before aging, although strength of alloys with 80% cold deformation is higher than alloys with 40% cold deformation, it's softening temperature is more low than alloys with 40% cold deformation, the softening temperature of 80%: 420°C,40%:440°C.7) Alloys with high hardness and electrical conductivity were obtained by using mulriple aging technics. Hardness: 139HV, electrical conductivity:98%IACS, alloys performance is equivalent with importation.