Acid pickling process of carbon structural steel tube

Abstract

The invention discloses a pickling process for carbon steel pipes. During pickling of steel pipes, a composite corrosion inhibitor is added to the pickling solution, and the composite corrosion inhibitor is prepared from the following components in mass percentage of: benzalkonium bromide 70~80%, zinc phosphide 8~12% and zinc carbonate 8~12%. The present invention adds a composite corrosion inhibitor to the pickling solution, which can form a layer of precipitation protective film on the surface of the steel pipe, which does not reduce the peeling speed of the oxide scale, but also reduces the corrosion of the steel matrix and the generation of hydrogen, and reduces the amount of hydrogen The generation of brittleness.

Description

technical field [0001] The invention relates to the technical field of steel pipe processing, in particular to a pickling process. Background technique [0002] With the continuous improvement of environmental protection awareness and the increasing pressure of environmental protection, H 2 SO 4 And the control requirements for the production of waste acid are becoming more and more stringent, and the production cost is constantly increasing. Therefore, it is imminent to reduce the production of acid and reduce the production of waste acid. [0003] During the pickling process of the steel pipe, the chemical reaction between the dilute sulfuric acid (the concentration of sulfuric acid is 20% and the temperature is 40-55°C) on the surface of the steel pipe and the steel pipe matrix is ​​mainly to generate hydrogen bubbles and emit heat. The external expansion pressure makes the scale peel off from the mechanical system of the steel pipe surface, and the chemical reaction is...

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Problems solved by technology

[0003] During the pickling process of the steel pipe, the chemical reaction between the dilute sulfuric acid (the concentration of sulfuric acid is 20% and the temperature is 40~55℃) on the surface of the steel pipe reacts with the steel pipe matrix to generate hydrogen bubbles and emit heat, resulting in a The external expansion pressure makes the scale peel off from the mechanical system of the steel pipe surface, and the chemical reaction is as follows: Fe+H 2 SO 4 =FeSO 4 +H 2 ↑, during the hydrogen precipitation process, a large number of acid droplets are taken away to form acid mist, which affects the physical and mental health of workers, and also corrodes the steel pipe substrate, consumes a large amount of sulfuric acid, and the market is accompanied by hydrogen embrittlement, making steel pipes useful The rate is reduced, affecting the efficiency of the factory

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