How to Protect the Corrosion of Railway Vehicle Fasteners?

We all know that in order to prevent the problem of corrosion, the fasteners on the railroad railway will be connected and installed with stainless steel materials, but these fasteners are in the assembly stage as the fasteners damage the coating during the fastening process. As a result, the fasteners are corroded. Therefore, it is also very important to remove rust and rust on fasteners on railways. The following Hook Bolt Manufacturer will share in detail how to protect railway vehicle fasteners from corrosion based on their understanding of fasteners.

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Listed below are pictures of corrosion of railway vehicle fasteners:

1. Analysis of the causes of fastener corrosion

High-resistance fastener is a kind of metal, and its corrosion principle is almost the same as that of other metal materials. In most cases, the corrosion of metal materials are the result of electrochemical reactions, but in some cases it is simply the result of pure chemical reactions or physical changes in metals, and these two situations occur at the same time and affect the corrosion of metal materials. Not uncommon. In addition, the material of the coating is damaged during the fastening process of the fastener.

The corrosion phenomena and mechanism related to the stainless steel body of railway vehicles are discussed below.

1.1 Pitting

Pitting corrosion is also called pitting corrosion or small hole corrosion. Due to the non-uniformity of defects, impurities and solutes in metal materials, when the medium contains certain active anions (such as CI), these active anions are first adsorbed at certain points on the metal surface, thereby making the metal surface The self-passivation film is destroyed. Once this layer of self-passivation film is damaged and lacks the ability of self-passivation repair, the metal surface corrodes. When the rail vehicles are parked in the harbour or transported by sea, they inevitably come into contact with seawater or salt mist formed by seawater.After parking at the seaside, salt particles form on the side walls to corrode; the exterior of the vehicle is in contact with acid rain. Under high heat and humidity

The self-passivating film is damaged, so that the surface of the fastener is uniformly spotted and rusty.

Once pitting corrosion occurs, if it cannot be removed in time, the newly exposed body metal is in an activated state, and part of the passivation film is still in a passive state, thus forming an active-passive corrosion battery. Since the area of the corroded anode is much smaller than the area of the cathode, and the anode current density is very large, the corrosion develops deeper, and the metal surface will be corroded into deep holes. The extent of pitting corrosion is large and small. In general, the depth of severe pitting corrosion is much larger than its diameter.

1.2 Physical damage

Physical reasons damage the coating of high-corrosion-resistant fasteners, which leads to corrosion of fasteners.

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