Experimental and numei̇cal investi̇gati̇on of steel pi̇pes formability withwith hydroforming

In this work exhaust pipe clamp adaptors are produced by hydrobulge forming. Aluzinc coated low carbon steel pipes are used in forming. Deformation behaviors of galvalume exhaust pipe connectors at the hydrobulge process are studied. The effects of design parameters on hydrobulge process is analysed by using explicit type finite element analysis (Ansys LsDyna). Pressure rate, unconstraint length, residual stresses, and spring back effect are considered in the analysis. Minimum thickness values obtained from the experiments are compared with finite element analysis (Fem). Relation between percentage of thinning and increasing pressure is studied. Strain hardening effects of galvalume cold-formed steel are implemented to Fem study. Failure of tubular parts is evaluated at forming limit diagram according to Hill- Swift criteria. The deformation characteristics of the produced connector headings are also discussed by scanning electron microscopy and microvickers hardening measurements. Maximum plastic strains and hardness are obtained at the middle of the form at the hydrobulge process. The ultimate tensile residual stresses and thickness reduction are determined at this region.