It is necessary to test the chloride index of garnet sand before sandblasting operation to reduce the production of soluble salt as much as possible. In sandblasting operation, if the air humidity in the operating environment is high and the chloride content of sandblasting abrasive is high, soluble salt is easy to be produced. After sandblasting and coating in this environment, penetrative foaming is easy to occur inside the coating. Corrosion and oxidation are achieved inside the workpiece, so we must test the chloride content index before spraying the garnet sand. In order to reduce the production of soluble salt as much as possible, the following issues should be noted in sandblasting operations:
(1) The humidity of the air when the garnet sand is blasted.
When the relative humidity in the air reaches 85% or the surface temperature of the object being blasted by garnet sand is less than 3 degrees Celsius, the sandblasting operation should be stopped.
(2) The time interval between blasting and painting of garnet sand.
In general, the garnet sand should be painted immediately after sandblasting, so that the contact time of the sandblasted object and the air is short, the dust and water content falling on the surface of the workpiece is less, and the best sandblasting effect can be maintained and the coating life can be longer. The best time interval between garnet sandblasting and painting is 4 hours, and if it is not painted for more than 6 hours, it is necessary to carry out secondary surface treatment.
(3) Detection of moisture and chloride content of garnet abrasive.
The requirements for abrasive moisture and chloride content of garnet sand blasting are less than 1%. If the content of both is too high, it is very easy to produce soluble salt.
With the development of science and technology, the application of garnet sand is more and more wide, the stock of garnet sand in China is very rich, and the price is suitable, can be reused, economic and environmental protection, in the field of sandblasting is an essential abrasive, garnet sand has begun to replace brown corundum in the Marine industry surface treatment status.
