Ductile Iron Cast Pipe is without any defects compare with tradition casting tech, which has many advantages particularly as follow:

(1) High density. In the "vertical upward casting" process, the melt iron of centre liquid column in center crystallizer is continuously feeding for volume shrinkage caused by condensation tube at outer circumference , which lead to be free of shrinkage porosity.

(2) High purity. When melt iron pouring, the mixed impurities such as gas, dross, sand grain which are lighter than melt iron could be eliminated at furnace mouth, its impossible to enter into the crystallizer through the channel, so the melt iron into the crystallizer is very pure.

(3) Strength with toughness. The cooling speed provided by continuous crystallizer is 30 times than sand casting and 5 times than centrifugal casting, and doesn't produce white iron, the eutectic cell volume of continuous cast iron is one eighth to one tenth compare with traditional cast iron. The density of graphite nodule in ductile iron can reach 300-700 pcs/mm2. Therefore, all reason above improve the strength and toughness of continuous cast iron.

(4) Free machining. The high speed cooling make the hardening phase (such as boride, steadite) not appear like reticular, massive or thick, but diffuse like fish bone and pane in shape, moreover, there are tiny graphite flakes inlaid hardening phase. It's free machining in BrinellHardness the range of 250-300HB. However, the Brinell Hardness of 250 is top limit to common metal materials.

(5) Uniform composition of tube wall. The convection mixing of liquid column caused by marching type drawing in crystallizer make the composition of tube wall well-distributed, and concentration gradient very little.

(6) High productivity. To the wall thickness of tube under 10mm, the speed of continuous casting is 1 meter/min, to the wall thickness of tube under 20mm, the speed of continuous casting is 0.5 meter/min, which is high efficiency that centrifugal or other casting tech couldn't reach.