Ductile iron pipes for thermal pipelines, its preparation process and application

Abstract

Disclosed is a spheroidal graphite cast iron pipe for a heating pipeline, comprising: a spheroidal graphite cast iron pipe body (1) having a spigot (12) at one end, a socket (11) at another end, and a microcrystalline thermal insulation layer (3) coated on an outer wall thereof. The spheroidal graphite cast iron pipe has strong corrosion resistance, a long service life and increased safety performance. The microcrystalline thermal insulation layer (3) has a high hardness, minimal thickness and excellent thermal insulation properties that not only facilitate the transportation and installation of the pipe, but also reduce heat loss during a heat transfer process. The invention also relates to a preparation process of a spheroidal graphite cast iron pipe for a heating pipeline. The spheroidal graphite cast iron pipe for a heating pipeline prepared by the process has no casting defects, such as slag holes, sand holes, blowholes, shrinkage cavities, shrinkage porosity, etc, and is air tight, demonstrating high pressure resistance capacity and high corrosion resistance, thereby greatly extending the service life of heating pipelines and significantly reducing construction and maintenance costs of heating pipelines. The invention can also be adopted to avoid damage to municipal engineering facilities and personal injury caused by leakage of high temperature steam or hot water.

Description

technical field [0001] The invention relates to a ductile iron pipe for thermal pipelines, its preparation process and application. Background technique [0002] At present, the heating and thermal pipelines used in cities and large industrial and mining enterprises in my country are laid with steel pipes coated with rock wool insulation, but these pipelines have the following problems: [0003] (1) Due to the poor corrosion resistance of steel pipes, especially the poor resistance to electrical corrosion, the design life of pipelines is not too long, and the actual service life is often less than 10 years, and some steel pipes are even corroded after 4 to 5 years Penetrating, causing high-temperature and high-pressure steam to leak out, wasting a lot of raw material resources and maintenance costs, especially the heating and thermal pipelines buried underground or under the road, the road surface needs to be dug up during maintenance, which seriously affects urban traffic, ...

AI Technical Summary

Problems solved by technology

[0003] (1) Due to the poor corrosion resistance of steel pipes, especially the poor resistance to electrical corrosion, the design life of pipelines is not too long, and the actual service life is often less than 10 years, and some steel pipes are corroded after 4 to 5 years. Penetrating, causing high-temperature and high-pressure steam to leak out, wasting a lot of raw material resources and maintenance costs, especially the heating and thermal pipelines buried underground or under the road, the road surface needs to be dug up during maintenance, which seriously affects urban traffic, and it will not be repaired in time. It is easy to cause a large amount of high-temperature steam leakage, causing casualties;

[0004] (2) The thickness of the rock wool insulation layer applied on the steel pipe is large, which increases the outer diameter and doubles the transportation cost; the strength of the rock wool insulation layer is very low, which is easy to cause damage during transportation and installation, resulting in losses;

[0005] (3) The steel pipes of the thermal pipeline need to be transported to the site for welding and pressure testing, etc., the operation is cumbersome, the construction period is long, and the construction cost is high, which increases the burden of municipal engineering construction investment and daily maintenance;

[0006] (4) The steel pipe of the thermal pipeline does not have the ability to resist strong earthquake damage, especially after several years of corrosion, after the pipe wall becomes thinner, the strength and toughness of the pipe are reduced to varying degrees. , twisted and hit by heavy objects, it is easy to break or even break

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