... the thin steel band is formed into the reinforced rib of the pipe, the ring stiffness contributed by ... thickness of steel band and the height of steel rib. In MRP pipe, polyethylene is just provide a ... is not too much, as well the steel rib material because the stiffness is already high enough.The ... out of corrosion. In MRP pipe, the steel rib is completely covered with polyethylene, the liquid, air ...