Warping of Stainless Steel Cookware

We manufacture 304 SS cookware.
The base of the cookware is as follows:
304 SS for pot Aluminium for heat spreading sandwich
304 SS cap which cover the aluminium.
This setup works fine.
We are experimenting with induction stove friendly pots.
We replaced the 304 SS cap with 430 SS as 430 is a ferritic steel.
After brazing and as the pot cools the base of the pot takes on a dome shape. I presume it is because of diff expansion rations of the metals.
Any ideas to solve the problem? Diff steel? Different method?
Any help will be appreciated.
Basheer Noorgat (NB. Remove "dashes" from email) NMC Waterless Cookware South Africa htpp://www.nmcexquisite.com
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.