Effective method of tin-free foundry bronzerefining from endogenous origin impurities

Abstract

Problem statement. Ukraine in the ranking of leading suppliers of castings from copper alloys is among the top ten. In recent years there has been a rapid rise intheir production. This is due to expansion of demand for copper alloys not only in electrical engineering,  but  also  in  other  areas  of  industry,  in  particular  in  automotive  manufacturing  of  electric  cars  production. Purpose. Copper-aluminum-iron  system  alloys  structure  formation  regularities  analysis  depending  on  amount  of  alloying  components changing  for  technological  recommendations  development  of  a  stable  high  level  of  mechanical  properties  of  foundry  bronzes obtaining  in  industrial  production  and  operation.  Material  and  Methods. Material  of  the  study  was  casting  bronze  BrA9Zh3L according to GOST 493 requirements. Microstructure was investigated on metallographic specimens prepared according to standard methods  as  per  ASTM  E3-11.  Analysis  was  performed  using  light  microscopy  on  "Neophot-2"  equipment.  Scanning  electron microscopy and X-ray spectral microanalysis were performed on Superprobe−733 equipment. Results. With the help of Cu, Al, Fe components binary and triple systems equilibrium diagrams studies results comparative analysis, X-ray spectral microscopy and local X-ray energy dispersion methods the controversial issue concerning iron-containing phase in BrA9Zh3L bronze structure origin has been solved. It has been found that this is β1phase, i.e. Fe3Al with dissolved copper atoms (up to 7,72 wt. %) and zinc in amount from 0,0 wt. % to 0,68 wt. %, depending on this component  content  in alloy.  Centrifugal casting method effective technological parameters industrial testing have been discovered that itsdisadvantages associated with bundle of casting material liquation can be used in production as advantage for melt included endogenous origin impurities refining, in particular, iron-containing Fe3Al phase. Conclusions. Controversial issue concerning iron-containing phase in bronze BrA9Zh3L structure genesis has been solved. It has been  established  that  this  is  a  phase  of  endogenous  origin  β1,  that  is,  Fe3Al.  Centrifugal  casting  method  effective  technological parameters for the melt included endogenous origin impurities refining have been used in production.