508的管子周长是多少
压力管道标准规格DN公称直径Ф-外径大外径系列DN15ф22mm,DN20ф27mmDN25ф34mm,DN32ф42mmDN40ф48mm,DN50ф60mmDN65ф7673mm,DN80ф89mmDN100ф114mm,DN125ф140mmDN150ф168mm,DN...
压力管道标准规格DN公称直径Ф-外径大外径系列DN15ф22mm,DN20ф27mmDN25ф34mm,DN32ф42mmDN40ф48mm,DN50ф60mmDN65ф7673mm,DN80ф89mmDN100ф114mm,DN125ф140mmDN150ф168mm,DN...