Some doubts about bearing and bearing steel rust(2)

Question 4: Will bearings made of GCr15 bearing steel rust in an outdoor environment?
Yes, and it is very rusty like ordinary steel. The Cr content of this steel is too small. The value behind the bearing steel is the Cr content, the unit is one thousandth, and the Cr content of GCr15 is only About 1.5%, if the Cr content is close to the 13% boundary, the anti-rust effect will be better. For example, Cr12 (containing about 12% Cr) steel will basically not rust.
Question 5: Can bearing steel be rust-proof?
Although the content of Cr in bearing steel is relatively high, it has a certain anti-rust effect, but the Cr content of 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. The Cr of steel is to improve the hardenability, not to prevent rust. Like ordinary metals, a humid environment can cause corrosion. Therefore, anti-rust measures for bearings and their parts are still very necessary.
Question 6: How to prevent bearing rust?
1. Surface cleaning method:
Cleaning must be based on the nature of the surface of the anti-rust material and the prevailing conditions, and an appropriate method must be selected. Generally, there are solvent cleaning method, chemical treatment cleaning method and mechanical cleaning method. When the surface is dry and clean, it can be dried with filtered dry compressed air, or dried with a dryer at 120~170℃, or dried with clean gauze.
2. Method of applying anti-rust oil
(1) Soaking method: Some small bearings are immersed in anti-rust grease and a layer of anti-rust grease is adhered 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 immersion or spraying. When brushing, it is necessary to pay attention not to accumulate, but also to prevent leakage.
(3) Spray method: Some large bearings cannot be oiled by immersion method. 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 complete fire protection and labor protection measures must be adopted.