I'm working on a lubrication system for a US military project and have had a little trouble sourcing 70/30 CuNi flanges, fittings etc. through a mfg that has experience with military projects. Can anyone point me in the right direction? Thanks.
You could get forged or cast material depending on how you either spec it or who supplies it. If the material is to be a cast flange, make certain to ask for a weldability test per ASTM B369.
Are you involved in the design end? If you are unfamiliar and the project is military, one of the pitfalls you have to be aware of is that the flanges are generally not to B16.5, they are to mil-specs and drawings.
I think you'd need the spec that was called out for the flange. My guess is that machined from plate wouldn't be OK. I'm not familiar with the AWWA C207 spec but think the use of plate for flanges is limited to blind flanges and reducing flanges w/o hubs in B16.5.
I've seen allowances for the use of slip-on flanges made from plate cu-ni but the use of those flanges is limited.