Without further details about your situation, no one can help you. Please provide details about the current bolting, design & service conditions, medium, perhaps a sketch, design code, etc.
A simple A2-70 hex bolt is cheaper but may (and will probably not) be sufficiently corrosion resistent, or resistent for other reasons, as there will likely be a good reason why youre currently using C276 bolting.
No, the only other options are more expensive.
I would suggest that you think about running method "C" and not using the crevice washers.
The repeatability on "D" is very very poor.
Dear EdStainless
Thanks for your recommendation
but Method C just for Pitting and can not cover Crevice.
we need to test crevice critical temperature.
can we use steel with coating for example Xylene or some thing like this?
or for second option what about using Ertalon bolt ( desired torque in ASTM G48 is 0.28nm)
No, if you change the bolt you are not complying with the test.
It must be metal so that it is rigid, and it must fully resist corrosion in the test solution, so all coated options are out.
Good luck, If I had to do crevice work today I would used an electrochemical method. We have moved all of our testing to pitting tests. At least there we can get tests to match withing 10C. In crevice +/-10C is a very typical spread on results.
