Al Alloy Sheets & Plates for Superstructures in Naval Warship

Aluminium alloys in the form of sheets and plates are extensively used for the manufacture of superstructures of naval warship. Such alloys must be weldable and having a combination of medium strength and virtual immunity to stress corrosion cracking and exfoliation corrosion. Aluminium‐magnesium alloys are, therefore, used for such applications.

Technology Developed at DMRL

The technology involving optimization of DMR291A alloy composition, formulation of various thermal and deformation process parameters including homogenization treatment, hot rolling parameters to realize plates in M temper, cold rolling parameters and post cold rolling annealing cycle to realize sheets in H24 temper has been developed. The process parameters at all the stages have been optimized. The grain structure of the alloy is suitably developed so as to avoid the exfoliation corrosion.The resultant materials are weldable and not susceptible to stress corrosion cracking and exfoliation corrosion.

Application Areas

• Superstructures of naval warship
• Space applications in different heat treatment tempers

The products made using the indigenous technology have achieved the entire range of properties for the targeted applications equivalent to those of the imported materials.

Tensile Properties of Indigenized Al Alloy AA5086