Hot Press Forging as the Direct Recycling Technique of Aluminium – a Review

Aluminium is totally recyclable with no downgrading of its qualities, but in the process of typical conventional aluminium recycling, there are quite a number of negative impacts. The recycling of aluminium and its alloys by direct recycling method is relatively simple, consumes small amount of energy, produce small amount of waste and does not have a harmful effect on the environment. This approach use hot press forging which eliminated two pre-process steps which typically introduce in conventional and semi-direct recycling. Hot press forging of aluminium 6xxx series is hot working process which means that the alloys should be heated around 460-520 °C, slightly above the recrystallization temperature. After heating the material, 1 to 2 hours of soaking times are sufficient to redissolve the aluminium under the flow stress less than 47 MPa. Review on recycling aluminium chips using hot press forging show that there are good potential of strength and plasticity. This is proved that such recycling technique could be employed as an alternative method to replace the conventional aluminium recycling process.