A kind of nodular cast iron pipe with waterproof protective layer and its production process

Abstract

The invention discloses a ductile cast iron pipe with a waterproof protective layer and a production process thereof. The method comprises the following steps of: (1) performing surface treatment on the ductile cast iron pipe to remove surface oxides thereof; (2) spraying a zinc protective layer; (3) spraying a stainless steel protective layer; and (4) coating an enclosed corrosion-resistant protective layer. The invention has the advantages that: the zinc protective layer, the stainless steel protective layer and the enclosed corrosion-resistant protective layer are sequentially sprayed at the periphery of the ductile cast iron pipe through an arc spraying method, and a sacrificial anode protection function of the zinc protective layer, the wear resistance and corrosion resistance of thestainless steel coating and the hole-sealing corrosion inhibition performance of the enclosed coating can be cooperatively exerted, so that the ductile cast iron pipe is well protected. The ductile cast iron pipe with the coating structure has high corrosion resistance in a hydraulic environment, the waterproof protective layer has a neat appearance, covers uniformly and densely, has long protection period, high corrosion resistance and high damage resistance, secondary excavation construction is not needed, and the life cycle cost of a project is obviously reduced.

Description

Technical field [0001] The invention relates to a ductile iron pipe with a waterproof protective layer and a production process thereof, which is suitable for ductile iron pipes laid in a hydraulic environment. Background technique [0002] For a long time, nodular cast iron pipes have a zinc protective layer plus a closed anti-corrosion protective layer as a composite protection system. This is a sacrificial anode plus cathodic protection anti-corrosion system. It has the advantage of long anti-corrosion years and is widely used all over the world. However, in the pipeline laying process, sometimes it will be blocked by rivers. In the past, ductile iron pipes with the above protection system were usually laid along the riverbed and across the riverbed. Such ductile iron pipes are subject to the impact of water flow and sand for a long time and corrode quickly. Decades of construction experience has proved that the protection period of zinc-sprayed ductile iron pipes in hydraulic...

AI Technical Summary

Problems solved by technology

However, during the pipeline laying process, sometimes it is blocked by the river. In the past, the ductile iron pipes with the above-mentioned protection system were usually laid along the river bed and crossed the river bed. Decades of construction experience have proved that the protection period of zinc-sprayed ductile iron pipes in hydraulic environments is about 15 years. Its advantages are reliable and stable anti-corrosion performance, good effect, and strong impermeability. The disadvantage is that the surface hardness is poor. Insufficient wear resistance, weak damage resistance

[0003] In addition, according to relevant data at home and abroad, the protection period of the stainless steel protective layer is about 45 years. Its advantages are high hardness, good wear resistance, high strength, and good damage resistance. No cathodic protection function, rough surface, strong water permeability, poor covering compactness, easy to peel off

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