Introduction of pickling bubbles in packaging steel strip pickling technology

The appearance of pickling bubbles is small bubbles, as small as the needle, as large as the palm.If the bubble is opened, the inner wall can be found smooth, sometimes with inclusions.After the bubble rupture, the bubble shows a small black crack and expands through cold rolling crack, resulting in reduced mechanical properties of strip steel.Bubbles that break during cold rolling make a crackling explosion.Acid washing bubbles mostly appear in sulfuric acid pickling, boiling steel is more than calm steel.

Acids react with matrix iron to form atomic hydrogen, and a part of the hydrogen atoms diffuses and accumulates in lattice distortion regions or non-metallic inclusions near the surface of the strip, binding into hydrogen molecules within these “microscopic holes”.Because the hydrogen molecule can no longer spread, the hydrogen concentration and pressure in the “microscopic hole” rise to reach hundreds of atmospheres, and the huge pressure makes the surface bulge to form bubbles.

Since the pickling bubbles are caused by the diffusion of hydrogen atoms, the preventive measures should reduce the dissolution speed of iron and the hydrogen diffusion speed during pickling.First, follow reasonable pickling system; the incoming material should be pure, because arsenic, ladder, hydrogen sulfide, dioxide and other harmful impurities will reduce the pickling speed, accelerate the diffusion of hydrogen in steel; iron oxide content should be more, structure and thickness should be uniform, in addition, effective corrosion inhibitor should be added in the acid.

Linyi Huili Machinery Co., Ltd the former Junan Lingyun Steel Strip Plant, is located in Economic Development Zone of Junan County and adjacent to Rizhao-Dongming Expressway and Beijing-Shanghai Expressway with convenient transportation and excellent location.

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