How to form a protective film on A242 type 1 weathering steel plate

Rust stabilization process is commonly used.
Rust stabilization treatment is to use chemical method (rust liquid) on the surface of A242 type 1 weathering steel plate to make it produce rust stabilizing film. It is a kind of inhibiting rust flowing out of A242 type 1 weathering steel plate at the initial stage of use, so as to stabilize it.

The main stages are as follows:
The first stage: the A242 type 1 weathering steel plate begins to grow small rust spots. The rust spots of ordinary steel plate are relatively loose, and some of the rust spots with poor rust treatment may appear rust scales.

The second stage of long rust: the A242 type 1 weathering steel plate has less rust water, and the rust spots are smaller and thicker; the rust water of ordinary steel plate is more, and the rust spots are larger and thinner; the rust column of ordinary steel plate has serious tear marks, and there are black marks at the bottom of the workpiece.
The third stage of long rust: the A242 type 1 weathering steel plate has a clear and dense rust core layer, and the rust spots are closely adhered to form a protective layer, and the rust can hardly be removed by hand; the ordinary steel plate has a large amount of rust, and the whole rust skin may peel off and rust through. A242 type 1 weathering steel plate is inclined to reddish brown, ordinary steel plate is inclined to dark black.