Surface pretreatment method of anti-rust object:
1) surface cleaning: cleaning must be based on the nature of the surface of the rust and the conditions at the time, select the appropriate method. Generally used solvent cleaning method, chemical treatment cleaning method and mechanical cleaning method.
2) After the surface is dry and cleaned, it can be dried by filtered dry compressed air, or dried with a dryer at 120~170 ℃, or it can be dried with clean gauze.
coating method of antirust oil:
1) soaking method: some small items are soaked in anti-rust grease, so that the surface is adhered to a layer of anti-rust grease. Oil film thickness can be achieved by controlling the temperature or viscosity of the anti-rust grease.
2) Brushing method is used for outdoor construction equipment or special shaped products that are not suitable for soaking or spraying. When brushing, attention should be paid not only to avoid accumulation, but also to prevent leakage.
3) Spray method Some large anti-rust objects cannot be coated with oil by soaking method. Generally, filtered compressed air with a pressure of about 0.7Mpa is used for spraying in a clean air place. Spray method is applicable to solvent-diluted antirust oil or thin-layer antirust oil, but perfect fire prevention and labor protection measures must be adopted.
The main factors affecting metal corrosion:
Metal corrosion is caused by various internal and external factors, which can be summarized as follows: ① chemical composition and structure of metal material itself; ② metal surface finish (oxygen concentration difference battery corrosion);③ solution composition and pH value in contact with metal surface; ④ ambient temperature and humidity; ⑤ various environmental media in contact with metal surface.
Why does hand sweat cause metal corrosion?
Human sweat is a colorless, transparent or light yellow with a salty taste of weak acid liquid, its pH value is 5~6. In addition to containing sodium, potassium, calcium, magnesium salts, but also contains a small amount of urea, lactic acid, citric acid and other organic acids. When sweat and metal contact, will form a layer of sweat film on the surface of the metal, sweat film will cause electrochemical action on the metal, corrosion metal.
Sweating is inevitable. To prevent hand sweat from causing rust, production personnel should wear gloves, finger cots, or use special tools to take parts, and do not touch the product casually.
