Technology for maintaining and heating of nodular cast iron pipe coated with cement lining before paint spraying

Abstract

The invention discloses a technology for maintaining and heating of a nodular cast iron pipe coated with a cement lining before paint spraying. The technology comprises the steps that the nodular castiron pipe coated with the cement lining is placed in the natural environment for 4-5 h; the nodular cast iron pipe coated with the cement lining is placed in the environment with the temperature of 40 DEG C for 3 h; the nodular cast iron pipe coated with the cement lining is placed in the environment with the temperature of 60 DEG C for 2 h; the lining cement strength reaches about 80% of the original strength; the lining of the nodular cast iron pipe coated with the cement lining is ground through a multi-leaf grinding wheel; then the nodular cast iron pipe coated with the cement lining is placed in a steam heating furnace or a steam heating pond to be continuously maintained, the temperature of the steam heating furnace is 75-85 DEG C, the steam pressure is 0.1 MPa or above, the humidity is 100%, and it is guaranteed that the final lining cement strength reaches 100% or above of the original strength. According to the technology, the production efficiency of the whole technology process from maintaining to paint spraying is improved, and the pipe lining cement quality is improved.

Description

technical field [0001] The invention relates to a process for treating ductile iron pipes coated with cement linings, in particular to a process for maintaining the ductile iron pipes coated with cement linings and heating them before painting. Improvement of tube health and heating process before painting. Background technique [0002] At present, most of the ductile iron pipes (hereinafter referred to as "pipes") adopt the following process from health preservation to heating before painting: [0003] like figure 1 As shown, most of the pipes go through the three stages of natural curing, low-temperature curing and high-temperature curing in the health-preserving pool or furnace, and the cement lining the pipes has a certain strength (in order to facilitate the comparison of the strength after the process is improved, the "certain strength" here is "Let's call it "100% strength"), enter the pipe internal grinding process, the lining cement is polished, enter the gas heat...

AI Technical Summary

Problems solved by technology

[0004] There are some deficiencies in this pipe health preservation and heating process before spraying paint as follows: 1. After the pipe strength is preserved to the so-called "100% strength", the internal grinding speed is low (that is to say, the hardness is high and it is not easy to grind), and the internal grinding The efficiency is low; 2. The cement is brittle, and the improper operation of the inner grinding trolley will cause strong vibration, and the lining cement will easily cause mottling and roughness, which will seriously affect the appearance quality of the lining

3. After internal grinding, the pipe is heated in a gas heating furnace, and the water in the inner lining evaporates quickly, which can easily cause the inner lining of the pipe to dry out and be damaged. As time goes by, the inner lining does not have enough water during storage, and the cracks gradually increase. Formation of defective products

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