Industry knowledge
About the protection of rail bolts-What is railway bolt protective grease?
In order to prevent the rust of related bolts in railway lines, bridges, etc., railway bolt protective grease is usually applied during the installation and daily maintenance of the bolts for protection.
Grease protection mechanism
There are two main grease protection mechanisms: one is physical isolation protection, that is, a layer of grease is applied on the metal surface to isolate the metal surface from the environment to protect the metal from the erosion of corrosive media in the environment and prevent metal rust; the other is chemical reaction protection, that is, by adding anti-corrosion agents to the grease, the anti-corrosion agents contact the metal surface and form a firm and tightly arranged adsorption film on the metal surface, forming a multi-molecular layer of protective film, thereby preventing oxygen, moisture and acidic substances in the air from corroding the metal surface and playing a protective role.
Grease is mainly composed of base oil and additives. The base oil has an oil effect, that is, the base oil can be physically adsorbed on the metal surface with less polar molecules. At the same time, the hydrocarbon groups in the base oil molecules will penetrate into the directional adsorption of the rust inhibitor molecules, and use the van der Waals force to block the pores with the rust inhibitor molecules, so that the adsorption film on the metal surface is more compact and complete, and the polar molecules that are not adsorbed firmly are not easy to fall off, so that the metal can be protected more effectively.
However, the base oil alone cannot effectively block the corrosive medium. Generally, a certain amount of rust inhibitors, metal corrosion inhibitors, etc. are added to the grease to improve the protective performance of the grease. At this time, the base oil plays the role of a carrier, so that the rust inhibitors, metal corrosion inhibitors, etc. are evenly dispersed in the grease.
The alkaline rust inhibitor in the grease can react with the acidic corrosive medium. In addition to the neutralization of the alkali by some free carboxylic acids, the polymer carboxylic acid soap can also react with the corrosive acid to generate new salts and polymer carboxylic acids. This makes the grease have the effect of neutralizing, replacing and solubilizing certain polar substances.
The oil-soluble corrosion inhibitor in grease is a surfactant with an asymmetric structure. The polar part of the rust inhibitor molecule relies on Coulomb force or chemical bond to form directional adsorption on the oil-metal surface, thereby reducing the activity of the active centers on the metal surface, blocking the erosion of water molecules and oxygen molecules, and greatly slowing down the corrosion process; the non-polar part of the rust inhibitor molecule forms a hydrophobic protective film on the metal surface, blocking the movement of related charges or substances participating in the corrosion reaction, thereby greatly reducing the probability and rate of rust.
GNEE RAIL also provides railway rail products of various specifications, which are widely used in railway lines and industrial tracks of different grades. All rail bolts are produced strictly in accordance with international standards, with high strength, good wear resistance and strong corrosion resistance, ensuring smooth and safe train operation. We can also customize according to customer needs to meet diversified engineering needs.
