To ensure the quality of ductile pipe fittings, it is crucial that their chemical makeup does not exceed 0.30% phosphorus and 0.10% sulfur in its composition.
It is recommended that the maximum surface hardness for continuous cast iron pipes should be HB210, while for metal and sand centrifugal cast iron pipes, the maximum surface hardness should be HB230. It is important to adhere to these limits to ensure the quality of the pipes.
The compressed air is used as the medium for the air tightness test, and the pressure for the test should not fall below 0.3MPa (3kgf/mm2f).
Gray cast iron is the most suitable material for the construction of cast iron pipes. These pipes have a dense composition and are easy to cut and drill.
The use of the cast iron pipe may be hindered if there are apparent defects, such as cold partitions, cracks, dislocations, etc., on the inner and outer surfaces. Therefore, it is necessary to maintain a high surface quality with no such defects.
The thinning in cast iron pipes must not have various local defects exceeding (2+0.05T)mm. Repairs can be done with the approval of the purchaser; however, they must undergo hydraulic pressure and air tightness re-testing based on this standard.
It is imperative for sockets and sockets to conform to the aforementioned prerequisites, as well as ensuring that their sealing surfaces are free from continuous axial grooves and pockmarked surfaces.
It is acceptable for slight defects to be present in the socket flange, as long as they do not hinder its intended purpose. However, it is important that the outline of the flange be distinct and visible.
Bitumen or other materials should be applied to both the inner and outer surfaces of the coated pipe. In cases where it is necessary, the pipe may also need to be lined with cement mortar or left uncoated.
The water supply cast iron pipes should have a coating that is immiscible with water, devoid of any odor and taste, and free from any impurities.
