Data for 'Beitai' brand ductile iron pipes:

1) Standard dimensions and weight of N1 type joint (K9 class, 

standard effective length: 6m) 

;



2) Standard dimensions and weight of S type joint (K9 class, standard 

effective length: 6m)

;



3) Standard dimensions and weight of T type joint (K9 class, 

standard effective length: 6m)  

;



Manufacturing processes:

1) Smelting and molten iron spheroidization: after smelting in a 

    mid-frequency furnace, molten iron id treated with a spheroidizing 

    agent to adjust its composition.

2) Centrifugal casting and extraction from molds: water-cooled metal 

    mold casting is used on a centrifuge, with molten iron in the cupola 

    heated by an electric furnace. After being spheroidized, it is cast 

    into a pipe mold that is continuously turning at high speed. The 

    molten iron sets into a ductile iron pipe, which is cooled by water, 

    then extracted from the mold according to the set time.

3) Heat treatment: qualified cast ductile iron pipes are put into an 

    annealing furnace to attain the required metallographic structure.

4) Finishing: during finishing processes, the pipes pass through 

visual inspection, zinc spraying (if necessary), roundness checking, 

    internal grinding of spigots and sockets, hydraulic pressure testing 

    (or air testing), ring test chamfering, grinding, dimension checking, 

    mechanical properties tested etc, in order to ensure pipe quality. 

    All pipes are then externally coated with metallic zinc and sprayed 

    with bitumen according to the ISO8179 standard.

5) Cement lining: cement mortar is lined onto the internal surface 

    of each ductile iron pipe to prevent water from being polluted and to 

    increase transmission capabilities. All pipes are internally 

    centrifugal lined by cement mortar lining according to the ISO4179 

    standard.

6) Bitumen coating: to prevent corrosion and give the pipe a good 

    appearance, every ductile iron pipe is coated with bituminous paint, 

    meanwhile undergoing a quality inspection of the external coating.