Yes, first to say that this's really a basic matter but i've found all around a week & still facing difficulty, hope someone has patient to help me an answer then i can go further myself As in the attached picture, a few ones have done their calculations & showed the different wall thickness of pipe from 30~60 mm but my boss just made his hand calculation & said that we only need the wall pipe thickness from 5~10 mm. I confuse what is the correct equation of bending moment to find the necessary thickness that the pipe would not be deformed (use safety factor ~1.5) & where to put the Min. yield strength 235 (mpa) into. We have the OD = 210 mm, steel grade S235JRG2, total uniform load along 200mm at center from bearing mass 600 kg. Sorry for long post, looking for a detail formular or just show me which step should i do, thanks many in advanced.