Condition monitoring is an important method to improve the life of low-speed and heavy-load rolling bearings

Time：2020.03.12  Source：Roller Bearings Suppliers

The slewing bearing of the continuous casting machine of the steel making plant has the characteristics of low speed, heavy load, large size, etc. It is crucial equipment on the steel making production line, and its bearing manufacturing cost is high. This slewing bearing is a low-speed heavy-duty rolling bearing. It is a unique rolling bearing with a large bearing capacity and a low working speed, and it bears a large impact load during operation. He is often called Low-speed heavy-duty rolling bearings. Low-speed heavy-duty rolling bearings are located in the critical parts of the equipment. If a failure occurs, it will affect the production of the entire steel production line. The corresponding repair and replacement work cycle will be long, which will cause significant economic losses. Low-speed heavy-duty rolling bearings in steel plants have such an essential position in the enterprise, so if the service life of the equipment can be extended, it can improve the economic benefits for the enterprise.

How to extend the life of the equipment? You must do the following two things: one is to operate and correctly use the material; the other is to monitor the condition of the equipment and understand the current state of the machine, and then you can take corresponding measures to maintain the equipment. The current methods for condition monitoring are vibration analysis and oil analysis. For slewing bearings, due to the deficient speed, it is difficult for conventional vibration analysis methods to pick up such low-frequency signals, so it is difficult to monitor them with traditional analysis of vibration, and large-scale low-speed heavy-duty rotary machines are almost always greased Also, conventional oil analysis techniques cannot be used for condition monitoring. Therefore, it is necessary to use high-reliability and low-cost new technology. The particular solvent for grease can be applied to this slewing bearing. At the same time, the spectral and ferrous spectral analysis methods of oil can also successfully monitor the condition of this bearing. Wuxi Spark Bearing Co., Ltd is a modern high-tech professional high-quality roller bearings manufacturer. We provide not only high quality and cheap bearings to many countries in the world, but also offer comprehensive bearing services to our bearing buyers. Our bearing services can solve most of your problems. Our bearing services also often provide users with relevant knowledge and advice. Let's take a closer look at how to monitor the condition of the bearing.

Bearing parameters

We need to understand the bearing diameter, quality, type of grease, carrying inner and outer ring materials, rolling body material, etc. The more conventional oil is lithium-based, the inner and outer ring materials are Cr Mo, rolling body. The content is high chromium alloy steel.

Selection of monitoring instruments

The wear status of the bearings is monitored by atomic emission spectroscopy, demography, and electronic probe technology. The models of the device are as follows:

　　1. MOA oil spectrometer of Baird company;

　　2. The double iron spectrometer of Standard Oil Company;

　　3. Predict the company's rotary Ferro graph;

　　4. BX60 optical microscope from Olympus;

　　5. EPM810Q electronic probe.

Sampling method

The biggest problem with grease analysis is the authenticity of its samples. Grease has an entirely different feature from lubricating oil, that is, abrasive metal particles are not evenly distributed in the fat, which results in very different iron-like iron content in different parts. Therefore, it is necessary to ensure that the samples are as representative as possible. After a lot of tests, the following sampling methods were found to be very useful. First, mark the bearing circumference as a sampling point. Then wipe the contaminated grease from the outside of the bearing clean, while keeping the bearing running, squeeze out the old fat by adding new fat to the oil pump. Finally, the extruded fat was collected into plastic bottles from 4 sampling points.

Analytical method

Because grease is a solid or semi-solid substance, its viscosity is very high, and abrasive particles are all wrapped up. Therefore, the focus and difficulty of this work are to study the pretreatment method of the grease, that is to say, the abrasive particles in the oil must be separated, and their appearance must not be destroyed. Special solvent for lithium grease, it can completely dissolve the organic matter in the fat. In this way, the spectral and ferrous spectral analysis methods of the fat are unified with the spectral and ferrous spectral analysis methods of the lubricating oil. Since all friction pairs are made of steel, the iron content of the grease can be used to measure the wear status of the bearing. The fats obtained at the four sampling points are individually tested, and their average mass fractions are calculated so that that trend analysis can be performed.

Result analysis

1.Spectral analysis

In the test results, if the iron content in each sample is abnormally high, it means that the equipment is unusually worn. If it is compared with the typical bearing sampling results of the same type, the iron content is higher than 2-5, it means that the equipment has Severe abnormal wear.

2.ferrographic analysis

In the ferrous spectral analysis results, if there are a large number of coarse cutting abrasive particles, it shows that there is double-body abrasive wear between the two surfaces of the friction pair; if there are large sliding abrasive particles of considerable size, it indicates that the sliding wear comparison between friction pairs Severe; if oversized abrasive particles appear, it means that the bearing has a severe fatigue peeling phenomenon.

3. Electronic probe analysis

You can analyze the composition of large-size metal abrasive particles to determine where they came from, and which part failed.

Diagnostic recommendations

Based on the analysis results of the above equipment, it is determined which part has a problem and needs to be repaired or replaced. The use of spectral and ferrous spectral analysis techniques can complete the condition monitoring of low-speed and heavy-duty grease-lubricated rolling bearings, especially for bearings that have been deferred for service. Wuxi Spark Bearing can provide high-quality bearings, and can also provide you with complete bearing services to solve your bearing problems.