Analysis and calculation of the forming pressure for the production of a shock-absorber tube by liquid extrusion

The aluminum alloy shock-absorber tubes of a motorcycle were manufactured with liquid extrusion replacing die casting under pressure. Not only were the defects of gas holes, porosity and dress inclusion in the die casting under pressure eliminated, but also the rate of production was increased while the cost of production was decreased. In this paper, the process of forming a shock-absorber tube by liquid extrusion has been analyzed. Based on the analysis, the pattern for calculating the forming pressure has been simplified and an equation has been derived by using the formation work method. The calculated results tally with the actual situation.