I need to determine acceptable torque limits for the silicon carbide nozzles that we produce. They range in size from 4" up to a 16" nozzle(300lbs). The flanges have the same number of holes and the same bolt holes as Class 150 flanges. Bob
You need to work toward keeping all of the preload stresses on the flanges in compression--not bending/tension. You may need a thick metal "clamping ring" to allow this.
What sort of stresses are involved on the whole assembly--fluctuating or static?
the nozzles range in size from 4" TO 16". A 4" nozzle would see a max force of 500lbs, a 6" nozzle would see a max force of 1100lbs, a 8" nozzle would see a max force of 2000lbs, a 10" 3000lbs, a 12" 4500lbs, 14" 7000lbs, 16" 8500lbs. Bob
the load the nozzle would see is calculated by dead heading the nozzle. So inrelaity the nozzle may never see this type of load. the typical load on the nozzle while being used would be constant. Bob
In that case you don't require a high preload on the bolts. Just make sure all the mounting faces are FLAT in order to avoid imposing bending stresses and you should be OK.
Can you perform a trial and error test, or are you writing a spec?