Hi macvalsa,
Thanks a lot for your help information, your suggestion will be very useful for me, but I want to confirm except incolloy 825, whether monel 400 also very expensive, as you know it is DN3400 i cannot imagine how big and how weight it is. if the body and disc all use the same material, it will be much expensive. does cupro-nickel alloy like nickel aluminium broze is cheaper? which one is cheaper does it compare with Stainless steel?
Thanks in advance.