Steel-plastics composite pressure pipe and its production method

Abstract

The steel plastics composite pressure pipe includes external plastic layer, external adhesive layer, internal adhesive layer and internal plastic layer, between external adhesive layer and internal adhesive layer there is a galvanized or aluminium-plated steel tape. Its production method includes the following steps: preparing steel pipe, blanking, cleaning welded two edges, removing aluminium and zinc, at the same time of extruding to obtain formed pipe, coating thermal sol, high-frequency heating, pressing and coating external plastic layer for resisting corrosion so as to obtain the invented steel plastic composite pressure pipe.

Description

technical field [0001] The invention relates to a steel pipe, in particular to a steel-plastic composite pressure pipe and a production method thereof. Background technique [0002] At present, the composite pressure pipe industry is basically divided into two categories, one is aluminum-plastic composite pressure pipe, and the other is steel-plastic composite pressure pipe. When the inner diameter of the pipe is greater than 32mm, the steel-plastic composite pressure pipe is far superior to other metal-plastic composite pressure pipes in terms of cost performance due to its higher pressure resistance and lower manufacturing cost. The steel-plastic composite pressure pipes that appear on the market now mainly include the following types: steel mesh-skeleton steel-plastic composite pressure pipes, orifice-type welded steel-plastic composite pressure pipes, five-layer steel-plastic composite pressure pipes, and outer stainless steel pipes. Steel-plastic composite pressure pip...

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Problems solved by technology

However, it still fails to solve the problem of the plastic layer as a pressure-bearing layer, so that the pressure-bearing capacity of the pipe body is still affected by the operating temperature and environment

[0005] The five-layer structure steel-plastic composite pressure pipe overcomes the shortcomings of the above two pipes, but it has a fatal shortcoming, that is, because the middle layer of this pipe is a steel pipe welded by ordinary steel strips, when used for long-term transportation of water or corrosion When used in aggressive media or in humid environments, due to the oxygen permeability of polyethylene as the inner and outer plastic layers, the surface of the steel pipe will be oxidized at a low price in a weakly oxidizing atmosphere, forming a loose ferrous oxide layer

Due to the formation of the rust layer, the glue layer that acts as a bond between the steel and plastic layers fails, so that the steel pipe layer is separated from the inner and outer polyethylene layers, and the plastic layer loses its proper protective effect.

[0006] Although the outer stainless steel inner polyethylene steel-plastic composite pressure pipe solves the problem of pressure bearing and steel-plastic layering, its price is much higher than the price of the above-mentioned pipes

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