Method for removing scale on surface of titanium/titanium alloy strip

Abstract

The invention discloses a method for removing scale on the surface of a titanium / titanium alloy strip, comprising the following steps: (1) electrolysis of acidic aqueous solution: putting the titanium / titanium alloy strip in an electrolyte, using polarity alternated non-contact electrolysis to electrolyze, wherein, the current density is 15-25A / dm<3>, the electrolyte is an H2SO4 solution with theconcentration of 150-350g / L, the temperature range of the electrolyte is 60-85 DEG C, and the electrolyzing time is 60-200s; (2) pickling with a mixed acid: mixing an HF solution with the concentration of 10-30g / L with an HNO3 solution with the concentration of 100-200g / L to prepare the mixed acid, carrying out pickling on the surface of the titanium / titanium alloy strip with the pickling temperature of 20-60 DEG C and pickling time of 50-400s; (3) surface cleaning; and (4) surface drying.

Description

technical field [0001] The invention relates to a method for removing oxide scales of alloy materials, in particular to a method for removing surface oxide scales of titanium alloys. Background technique [0002] In the metallurgical process, in order to remove the scale produced by the hot rolling or cold rolling annealing of titanium / titanium alloy strips, the traditional method includes three steps: the first step is to use mechanical shot blasting to remove most of the scale on the surface of the strip ; The second step is to carry out the physical and chemical modification of the residual oxide scale with the mixed acid made of sulfuric acid or hydrofluoric acid and nitric acid, that is, to further remove; the third step is to remove the residual oxide scale with the mixed acid of hydrofluoric acid and nitric acid, and carry out surface passivation. [0003] There is following shortcoming in above-mentioned existing scale removal method: first, titanium metal is very a...

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Problems solved by technology

[0003] There is following shortcoming in above-mentioned existing scale removal method: first, titanium metal is very active, and the dust that mechanically peels off in shot blasting process is very easy to catch fire and explode, so must protect with inert gas such as expensive argon; Secondly, the whole oxidation The process of washing off the skin is more cumbersome

[0005] However, the above-mentioned methods are all suitable for the removal of scale on stainless steel strips, but hot-rolled or annealed titanium / titanium alloy strips have excellent chemical stability of the surface scale and high chemical activity of the base metal, so it is difficult to achieve acid removal. wash evenly

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