Internal pressure performance
Because of the terrain and water supply, pipeline has internal pressure at working condition, in addition to the unexpected situations,  will produce an instant high pressure (for example: water hammer), high performance is directly related to the pipeline’s life and long-term stable supply. 
Due to the excellent performance of ductile cast iron, ductile iron pipeline is much safer than other material’.
● Working Pressure Design, the value is higher than most other materials’ pipeline;
● safety factor is very high, the actual burst pressure is three times to the working pressure.

External Pressure Performance
● against external loads, reduce construction costs
Buried pipeline will bear some vertical loads (soil weight, vehicle dynamic load, pipe weight, water weight), and through pipe wall and soil bed, loads will be transferred to the ground, so soil bed should be compaction according to pipelines’ loading. High pressure performance of ductile iron pipelines can be reduced the requirements of soil bed and the protective layer, so pipeline is both reliable and economical.
● Automatic flexible joints, also for special terrain
Pipeline may pass through some soft or unstable areas (marsh, Subsidence caused due to groundwater extraction, mining, etc.). Huge mechanical stresses will be generated by earth movement; in this condition pipes should move with the earth movement, cannot try to resist earth movement, or to fall off and be broken. In the deflections degree and axial clearance range, push-on T-type joint allows pipeline change a little with earth movement, so that the design and construction difficulty is greatly reduced, and saving engineering investment.
After the 1979 earthquake in Miyagi, Japan, a study showed that ductile iron pipe damage was 0.04 times / km, while the failure rate of gray iron is four times to ductile iron, other materials are more than 30 times. 

Inner coating - cement lining
Product performance---inner lining anticorrosive
SUNS brand zinc coating ductile iron pipes inside lined by using centrifugal cement mortar protective layer. This protective layer is made of high quality and rigorous testing of cement raw materials, whole process controlled by computer. 
Cement lining quality complies with international standards ISO4179, to ensure lining strong, dense, smooth and good surface adhesion to iron surface, no falling, scaling, and thickness uniformity, ensure that the internal every inch pipeline have been protected very well.


Outer coating - sprayed zinc
Ductile iron pipe initiatively protect by electrochemical action between sprayed zinc and iron.
For SUNS, each ductile pipe’s outer surface are coated with zinc, by international advanced high-pressure fuel injection technology, minimum mass 130g / m2, according to ISO8179 standard.
● form a stable protective layer during contact with the soil, the zinc gradually and slowly transformed into a close, adhesions, continuous zinc layer. The outer layer of bitumen coating (sealing pores) as a film, make zinc into insoluble zinc salt rather than soluble zinc hydroxide.
● Self-healing injury,  sprayed zinc layer automatically repair scratched area protective layer. Zinc ions go through sealing pores (bitumen coatings) and migrate to the scratched area and converted to a stable insoluble zinc compound.


Joints---Tyton Type Joints
T-joint is world-famous because of its quick and easy installation and only need simple tools for installation. Because of this joint and the corresponding T-type gasket can withstand a greater deflection angle and greater tolerance, especially suitable for using in soft earth and bending area. T-type gasket is a self-sealing gasket, when the pipe internal pressure increases, the contact pressure between the gasket and the pipeline also increased, T-type joint not only allow a deflection angle of axial displacement, and quick and easy installation. During installation, simply put spigot into socket, with gasket at right position and will get a reliable sealing performance.

DN Allowable Deflection
Pipe end Displacement
60 ~ 150 ( 6m ) 52
200 ~ 300 ( 6m ) 42
350 ~ 600 ( 6m ) 32
700 ~ 800 ( 6m ) 21

Mechanical Properties

SUNS DI Pipe Annealed DI Pipe Casting DI Pipe Grey Iron Pipe
Yield Strength ≥ 300MPa ≥ 300MPa N/A N/A
Tensile Strength 430MPa ≥ 420MPa ≤ 300MPa ≥ 200MPa
Elongation ≥ 10% ≥ 10% ≥ 3% ≤ 3%
Broken Type Plastic deformation Plastic deformation Abrupt Broken Abrupt Broken