GB/T 38986-2020Methods of descaling and cleaning for zirconium and zirconium alloy surfaces (English PDF)

4.1

When heated below 540 °C, the oxide and oxide color produced on the surface of the zirconium material can be removed by pickling.

4.2

The proportion (volume) of the pickling solution is. 10%~45% nitric acid (68%) 1%~5% hydrofluoric acid (50%) water (the balance). If so

With other concentrations of nitric acid and hydrofluoric acid, you can refer to the above acid solution concentration for the corresponding conversion.

4.3

Pickling should be carried out at a temperature lower than 50°C, and the best pickling temperature should be close to 30°C.

4.4

The zirconium material after mechanical grinding or degreasing cleaning treatment can be immersed in acid liquid to complete the surface cleaning.

5.1

If the surface of the zirconium material has loose scales, it can be cleaned by impact descaling. The following items should be paid attention to.

a) The medium for impact descaling can be alumina, silicon carbide, silica sand, steel grit, steel shot, etc., and it should be replaced regularly during use.

b) Impact descaling may cause residual stress on the surface of the zirconium material and cause local deformation, so the thickness of the plate or

It is not recommended to use the impact dephosphorization cleaning method for the strip.

c) Zirconium materials are generally not pickled after impact descaling. But if there is pollution on the surface of zirconium material caused by interstitial elements (such as carbon, oxygen and nitrogen)

The layer cannot be completely removed by impact descaling, it can be removed thoroughly with pickling cleaning method.