FORMABILITY CHARACTERISATION OF TRI-PLY CLADDED SHEET METAL OF STAINLESS STEEL WITH ALUMINIUM IN CORE

Abstract

Today Clad sheet metals is seen to have their increasing popularity in various industrial applications like in automobile body parts, cookware manufacture, aerospace applications etc. the clad sheets have enhanced mechanical properties over the individual component of the clad sheet. They tend to increase strength, ductility, thermal conductivity, surface properties and contribute in overall reduction of weight. This present study is confined to a roll bonded tri-ply cladded sheet of AISI304 on one side AISI430 on other with AA1050 sandwiched in between them having combined thickness of 2.5mm. Firstly the peel strength the roll bond was tested as per ASTM-D1876 standard. The tensile specimens were laser cut in three different directions 00, 450 and 900 with rolling direction(RD) as per ASTM-E8M standard. The tensile properties like UTS, yield strength, ductility and strain hardening of clad sheet and individual sheets are tested and compared. The drawability of the clad sheet is determined by performing anisotropy test and determined the R value (Lankford value) in directions 00, 450 and 900 with rolling direction(RD) . All these tests are performed on 50kN Universal testing machine. The forming limit diagram(FLD) for the clad sheet is drawn by performing limit dome height(LDH) test on 100 tonne hydraulic press using 50mm hemispherical punch. The specimens are laser cut in dog bone shape in various widths from 20mm to 100mm. Die, holder and punch are fabricated by CNC milling from AISI D2 tool steel. A circular grid of 2.5mm diameter is laser etched on all the specimens for measurement of major and minor strains. The necking strains on the deformed circles were measured on the tested specimens and a forming limit diagram was plotted. Finite Element analysis is also carried out and the experimental results are found to be in good agreement with the FE results.