반용융 단조에서 가압 단계가 제품에 미치는 영향

The Influence of Compression Step on Products for Semi-Solid Forging

  • 최재찬 (부산대학교 정밀정형 및 금형가공 연구센타) ;
  • 박형진 (동의공업전문대학 컴퓨터응용설계과) ;
  • 이병목 (부산대학교 대학원)
  • 발행 : 1998.04.01

초록

The technology of Semi-Solid Forging(SSF) has been actively developed to fabricate near net shape products using light and hardly formable materials. Generally the SSF process is composed of slug is compressed during a certain holding time in order to completely fill the die cavity and accelerate the solidification rate. The decision of compression time is important since it can affect microstructural characteristics, mechanical properties and shape of products.. In order to determine it proper overall heat transfer coefficient between the slug and dies should be investigated. This paper presents the procedure to find the overall heat transfer coefficient between the slug and dies by nonlinear optimization of temperature and solid fraction for a cylindrical slug at compression step in closed-die semi-solid forging. In finite ele-ment heat transfer analysis release of latent heat during solidification was considered. The influence of the predicted compression time on miscrostructural characteristics mechanimcal properties and shape of products is finally investigated by experiment.

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