Aussie Carrier Welds

[Rusty]

Aussie carriers are of fully welded construction exept for a few rivets in the rear corners of the Victorian railways built units. South Australian railway units are fully welded.

All the hull seem welds are made using a steel type rod however a lot of brakets are welded with with stainless rods and to this day present as nice shiny welds. QUESTION why use two types of rods? why the expense of stainless welds?