Surface Pretreatment of Rod Ends
- Surface cleaning: The appropriate cleaning method must be based on the nature of rod ends’surface and the conditions at that time. Commonly used methods are solvent cleaning, chemical treatment cleaning and mechanical cleaning.What is a cleaning solvent?
Solvents are compounds that can be used to dissolve, soften, melt or extract another compound. Solvents are divided into two categories: organic and inorganic. Organic solvents contain carbon and are commonly used to remove stains, dry-clean fabrics, dissolve paint and remove glue. Inorganic solvents do not contain carbon and are rarely used outside professional research facilities except water.
Types of cleaning solvent:
Oxygen-containing solvents, as their names imply, contain oxygen molecular structures. Derived from petroleum products, they usually have low toxicity and high solvent capacity.
Hydrocarbon solvents These are petroleum based solvents whose chemical structures contain hydrogen and carbon atoms. Hydrocarbon solvents can have complex chemical structures.
Halogenated solvents These solvents contain halogen atoms in their molecular structures. Because they are usually stable, non-flammable, and they have high solvent capacity, they are widely used in industry for precision cleaning and many other applications.
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Surface drying: After the rod end is cleaned, it can be dried by filtered compressed air, or by a dryer at 120 – 170 C, or by a clean gauze.Coating Antirust Oil
- Immersion method: To immerse rod ends in rust-proof grease, so that their surface is adhered to a layer of rust-proof grease. Oil film thickness can be controlled by adjusting the temperature or viscosity of rust-proof grease.
- Brushing method: When brushing, pay attention to avoid accumulation and prevent leakage.
- Spraying method. Usually, the filtered compressed air of about 0.7Mpa pressure is applied to clean spray rod ends. Spraying method is suitable for solvent dilution antirust oil or thin layer antirust oil, but must take perfect fire protection and labor protection measures.
What are the main factors affecting metal corrosion?
Metal corrosion is caused by various internal and external factors. It can be summarized as follows: 1) chemical composition and structure of metal material itself; 2) temperature and humidity; 3) all kind of materials contact with metal surface.
Why does hand sweat cause metal rust?
Human sweat is a colorless, transparent or yellowish liquid with salty taste and weak acidity. Its pH value is 5-6. In addition to sodium, potassium, calcium, magnesium salts, it also contains a small amount of urea, lactic acid, citric acid and other organic acids. When sweat contacts with metal, a layer of sweat film will be formed on the metal surface. The sweat film will cause electrochemical reactions and cause metal rust.
Sweat is inevitable. To prevent hand sweat from causing rust, do not touch products with hands. You should wear gloves, fingerprints, or use special tools.