A Long-Lasting, High-Temperature, and Heavy-Duty Solution for Grinding Roller Bearings in Thermal Power Vertical Mills

Why do vertical mill equipment in the thermal power industry require lubricating grease to be low-speed, heavy-load, high-temperature resistant, and impact-resistant?

The grinding roller bearings of vertical mill equipment in the thermal power industry operate continuously under conditions of 90–130°C, low speed of 20–40 r/min, and combined loads exceeding 150 kN, which places clear requirements on the low-speed load-bearing capacity and high-temperature resistance of the bearing grease.

When grinding raw coal and limestone, the vertical mill rollers with a diameter of 1500–2600 mm revolve at 20–40 r/min, and the equivalent dynamic load borne by the bearings often reaches 150–250 kN.

Dust intrusion through weak points in the seal is the primary cause of failure. The dust concentration in a vertical mill system can reach 30–80 g/m³, and once hard particles with a diameter of 5–50 μm penetrate into the bearing cavity of the grinding roller, the dust can cause serious damage.

The cleanliness and corrosion resistance of grease directly determine the life of the raceway and are also a prerequisite for extending the grease change cycle.

The roller surface is subjected to the combined effects of grinding heat and hot air heating, and the temperature measurement point of the bearing housing fluctuates between 90 and 130°C year-round, with 140°C approaching the upper limit for most greases.

The grinding roller also withstands impact loads from materials with a feed particle size of 0–50 mm and a Mohs hardness of 3–4, with instantaneous peak values reaching 1.5–2.0 times the equivalent static load.

Frequent downtime for grease or oil changes increases maintenance costs. The original thin oil lubrication required a circulating oil station, cooling and filtration devices, and a single maintenance took 8-12 hours, with a total of 60-90 hours of unplanned downtime per year. 

What are the key physicochemical parameters of YBS-BE 41-1501 bearing grease?

YBS-BE 41-1501 bearing grease has a working cone penetration of 310–340 (0.1 mm, DIN ISO 2137), an NLGI consistency grade of 1 (DIN 51818), and a dropping point of approximately 170°C (DIN ISO 2176).

The parameters in the table below are taken from the product's typical data sheet. Actual measured values are based on the COA (Certificate of Account) upon delivery.

For items not listed in the table, such as low-temperature torque, similar viscosity, four-ball wear scar, evaporation loss, and stencil oil separation, testing can be conducted according to GB/T 12917, SH/T 0048, GB/T 3142, GB/T 7325, and SH/T 0324 respectively. The actual measured values shall be based on the COA received.

The calcium sulfonate thickener gives the grease good corrosion resistance and is compatible with NBR elastomer seals, making it suitable for sealing systems of vertical mill roller bearings.

Special solid lubricants provide emergency lubrication performance under boundary lubrication and shock loads, and when combined with high-viscosity base oils at approximately 1500 mm²/s at 40°C, they maintain a reliable lubricating film under low-speed heavy loads.

What are the effects of replacing the grinding roller bearings of a vertical mill manufacturer in East China with YBS-BE 41-1501?

After the vertical mill roller bearings of the No. 3 coal mill were replaced with YBS-BE 41-1501, a manufacturer of vertical mill equipment in the thermal power industry in East China operated the mill continuously for 6,000 hours without any lubrication-related shutdowns.

The original product was L-CKD 220 heavy-duty industrial gear oil (GB 5903) thin oil circulating lubricant, not grease.

The failure modes are as follows: leakage at the end seal of the grinding roller shaft, emulsification and deterioration of the oil after being contaminated by dust, and a shortening of the filter element replacement cycle of the circulating oil station to about 2,000 hours.

During the low-temperature start-up phase, the oil film builds up slowly, and preheating is required after shutdown in winter, which increases the auxiliary machine energy consumption by 1-2 hours.

After replacement, the circulating oil station was eliminated, and the bearing housing temperature stabilized below 95°C, operating within the product's operating temperature range of −10°C to 140°C.

The NBR elastomer seals are compatible with this grease, and leakage and emulsification issues no longer occur. Low-temperature startup is also normal. The test duration is 6,000 hours of continuous operation (approximately 8 months) with on-site follow-up.

Data source: Jialede laboratory bench test (method GB/T 3142 four-ball method, to verify extreme pressure anti-wear performance), Q2 2026; and reference to the above-mentioned manufacturer's on-site tracking records (Q2 2026).

The above are typical tracking results. Specific values may vary depending on operating conditions and load. Actual measurements should be based on the COA upon delivery and on-site monitoring.

What are the differences between YBS-BE 41-1501 and the original gear oil/thin oil lubrication under vertical mill operating conditions?

Under the same vertical mill roller bearing operating conditions, the kinematic viscosity of the base oil of YBS-BE 41-1501 at 40°C is approximately 6.8 times that of the original L-CKD 220 gear oil (approximately 1500 vs. 220 mm²/s), and it contains special solid lubricants.

The table below provides an objective comparison of lubrication methods and key performance indicators, distinguishing only by applicable scenarios and not involving any negative brand evaluations.

Gear oil thin oil lubrication has advantages in heat dissipation and high-speed operation; YBS-BE 41-1501 is designed for vertical mill grinding rollers operating at low speeds of 20–40 r/min and combined loads of 150–250 kN.

The two lubrication methods should be selected based on the operating conditions, rather than judging their superiority or inferiority based on a single indicator.

In which scenarios is YBS-BE 41-1501 bearing grease unsuitable?

When the continuous operating temperature of the grinding roller bearing exceeds 140°C, it exceeds the upper limit of the operating temperature specified in the YBS-BE 41-1501 data sheet. A product with a higher temperature rating should be selected or additional cooling measures should be added.

The following three types of boundary conditions need to be identified in advance:

• Over-temperature conditions : Do not use when the temperature is continuously >140°C (dropping point is about 170°C). You need to evaluate replacement or forced cooling solutions.
• Low temperature limit : When the ambient or start-up temperature is below −10°C, the pumpability of long fiber liposomes decreases, requiring preheating or selection of low-temperature products.
• Sealing material : The data sheet confirms compatibility with NBR elastomer seals. Compatibility should be confirmed before contact with other elastomer materials.

The above boundaries do not represent product defects, but rather clearly define the applicable boundaries to avoid misuse under non-target operating conditions that could lead to unexpected wear.

Disclaimer

The parameters in this article are taken from the typical data sheet of Youbangshou® YBS-BE 41-1501 product. Actual measured values are based on the delivered COA and do not constitute a performance commitment for any specific batch. The runtime and temperature data in the case study are typical tracking results from a vertical mill equipment manufacturer in the thermal power industry in East China and bench tests conducted by Jialede Laboratory (Q2 2026). Actual performance fluctuates depending on operating conditions, load, and sealing conditions. This article does not cite any third-party report numbers, ISBNs, or customer names, nor does it make any negative evaluations of competing brands. Please contact the Jialede technical team for operating condition adaptation and compatibility confirmation before selecting or replacing a product.

Last updated on September 17, 2026