Some problems of rusting of bearings and bearing steel


  Question 1: Will the bearing steel rust? will ru […]


Question 1: Will the bearing steel rust?
will rust. Bearing steel, including stainless steel, rusts.
Although stainless steel is called stainless, it is actually rusty. In fact, there is no stainless steel in the world!


Question 2: How does the bearing steel rust?
The so-called stainless steel refers to the different degrees of corrosion resistance.
Corrosion rate < 0.01mm/y, considered "complete corrosion resistance";
If the corrosion rate is less than 0.1mm/y, it is considered "corrosion resistant";
If the corrosion rate > 0.1mm/y, it is considered "not corrosion resistant", that is, general steel.

Except for a small part of the bearing steel, most of the bearing steel is ordinary corrosion-resistant steel, so it is not surprising at all to get rusty, it is normal.


Question 3: Why does the bearing rust?
The rust of the bearing is related to the material and the use environment. The bearing steel itself contains carbon components, which will react when encountering water vapor. If you want to prevent the bearing from rusting, you must do a good job of anti-rust treatment. Or use non-steel bearings.

Metal products are prone to rust after oxidation, and stainless steel bearings are no exception. There are many factors that affect its rusting: such as the chemical composition and structure of the metal itself; surface finish (battery corrosion due to oxygen concentration difference); the composition and pH value of the solution in contact with the metal surface; and its environment and many other factors, these All are the direct factors that make the bearing rust.

In addition, when we use the bearings, we must not directly touch the objects with our hands, because when the sweat comes into contact with the bearings, a layer of sweat film will be formed on the surface of the bearings, which will cause electrochemical effects on the bearings and corrode the bearings. Therefore, we need to use special tools such as special gloves or finger cots to take the bearings, and do not touch them directly with hands.



Question 4: Will bearings made of GCr15 bearing steel rust in an outdoor environment?
Yes, and it will rust very much like ordinary steel. The Cr content of this steel is too small. The value behind the bearing steel is the Cr content, and the unit is one thousandth. The Cr content of GCr15 is only About 1.5%, if the Cr content can be close to the dividing line of 13%, the anti-rust effect will be better. For example, Cr12 (containing about Cr12%) steel will not rust much.


Question 5: Can the bearing steel be rust-proof?
Although the Cr content of bearing steel is relatively high, it has a certain anti-rust effect, but the Cr content of the steel is small, and the Cr content of GCr15 is only about 1.5%. At this time, the Cr element plays a role in improving the mechanical properties of the steel. Cr in steel is used to improve hardenability, not to prevent rust. Like other metals, damp conditions can cause corrosion. Therefore, antirust measures for bearings and their parts are still very necessary.


Question 6: How to prevent the bearing from rusting?
1. Surface cleaning method:
Cleaning must be based on the nature of the anti-rust surface and the conditions at that time, select the appropriate method. Commonly used are solvent cleaning method, chemical treatment cleaning method and mechanical cleaning method. When the surface is dry and cleaned, it can be dried with filtered dry compressed air, or dried with a dryer at 120~170°C, or wiped dry with clean gauze.

2. Method of coating anti-rust oil
(1) Soaking method: some small bearings are soaked in anti-rust grease, and a layer of anti-rust grease is attached to the surface. The thickness of the oil film can be achieved by controlling the temperature or viscosity of the anti-rust grease.

(2) Brushing method: It is used for large bearings that are not suitable for soaking or spraying. When brushing, pay attention not only to avoid accumulation, but also to prevent leakage.

(3) Spray method: Some large bearings cannot be oiled by immersion method, and generally use filtered compressed air with a pressure of about 0.7Mpa to spray in clean air. The spray method is suitable for solvent-diluted anti-rust oil or thin-layer anti-rust oil, but perfect fire prevention and labor protection measures must be adopted.

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