1、 The natural color can be boiled and dried with sulfuric acid soap solution for 3-5 years.

2、 Phosphating: the process in which steel is treated in a solution dominated by phosphating solution and a layer of water-insoluble crystalline phosphoric acid film is deposited on the surface.

3、 Benefits of dephosphorization: cold upsetting phosphating is to make cold upsetting well formed. Descaling after cold upsetting can eliminate the cold brittleness of parts, and is good for electroplating. After dephosphorization, the surface of parts is not easy to conduct electricity.

4、 Phosphating process is divided into impregnation method and spray method: 1. Impregnation method: suitable for high, medium and low temperature phosphating process, and can handle workpieces of any shape. The utility model is characterized in that the equipment is simple and does not need phosphating tank and heating equipment. The tank is lined with stainless steel or rubber, and the stainless steel heating pipeline is placed on both sides of the tank. 2. Spray method: it is suitable for medium and low temperature phosphating process and can deal with large-area workpieces, such as automobile, refrigerator and washing machine shell. It is characterized by short treatment time, fast film-forming reaction speed and high production efficiency. The general phosphating process flow of iron and steel is: chemical degreasing - hot water washing - cold water washing - Pickling - cold water washing - phosphating treatment - cold water washing - post phosphating treatment - deionized water - drying.

5、 Alkaline blackening process: degreasing - clean water cleaning - Pickling - clean water cleaning - blackening - passivation - clean water cleaning - oiling and rust prevention.