Acid pickling technology for welding wire steel surface pretreatment

Abstract

The invention discloses an acid pickling technology for welding wire steel surface pretreatment. An acid pickling solution adopted in the acid pickling technology is prepared from, by mass, 8%-16% of sulfuric acid, 4%-10% of hydrochloric acid, 0.5%-1% of fatty alcohol-polyoxyethylene ether, 1%-2% of thiourea and the balance water. The acid pickling technology comprises the following steps that 1, welding wire steel is immersed into clear water with the temperature ranging from 55 DEG C to 60 DEG C to be soaked for 5 minutes to 8 minutes; 2, the acid pickling solution is prepared and then poured into an acid pickling tank; 3, the welding wire steel soaked in the clear water is put into the acid pickling tank to be subjected to acid pickling, wherein the acid pickling temperature ranges from 20 DEG C to 35 DEG C, and the acid pickling time ranges from 30 minutes to 40 minutes; 4, the welding wire steel obtained after acid pickling is washed with clear water and then coated with boric acid for rust prevention. According to the acid pickling technology, sulfuric acid and hydrochloric acid are adopted to be cooperatively used, the acid pickling time is short, and steel scale cinder can be removed more effectively; fatty alcohol-polyoxyethylene ether not only achieves an corrosion inhibition effect, but also can generate a layer of foam with the acid pickling solution in the acid pickling process, therefore, the condition that acid mist is volatilized into space to generate pollution is prevented, and the environment is protected.

Description

technical field [0001] The invention relates to the technical field of steel surface treatment, in particular to a pickling process for welding wire steel surface pretreatment. Background technique [0002] When low-carbon steel is heated to 575-1370°C in air, a high-temperature oxide scale will be produced on the surface of the steel due to high-temperature oxidation. The thickness and composition of the oxide scale depend on the duration and temperature of heating. The inner layer of the high-temperature oxide skin is dark brown FeO, which is a clean structure with loose pores. The interconnection between the grains is weak and easily damaged. The middle layer is Fe3O4, which is relatively dense, and the outermost layer is Fe2O3, which has a dense structure. . Generally, the scale is mainly FeO, with the least content of Fe2O3. The content of each layer of the scale is not fixed, and the proportion is roughly as follows: FeO 40%-95%, Fe3O4 5%-60%, Fe2O3 0-10%. [0003] O...

AI Technical Summary

Problems solved by technology

At this stage, all manufacturers are using a single sulfuric acid to react with iron to generate bubbles to remove scale, and the reaction between sulfuric acid and scale components is relatively slow

However, some oxide scales are firmly bonded to the matrix iron, and sulfuric acid cannot directly enter the oxide scale and react with the iron matrix.

However, the reaction between hydrochloric acid and various scales is very violent. Using a single hydrochloric acid will form a strong acid mist due to the volatilization of hydrochloric acid, causing environmental impact and personal injury.