Thread Content
I. Is it normal for the oil to turn black during use? Answer: There are three reasons for oil discoloration: (1) Degradation of the lubricating oil. (2) Part wear. (3) Impurities enter the fuel tank. If no impurities enter the oil tank during use, it can be assumed that there is a problem with the quality of the lubricant itself, and the brand of oil should be changed. It is normal for the color of the lubricant to darken slightly after being used for some time, but it should not turn very black (this does not apply to engine oil). II. Can older equipment use lower-quality oil? Answer: Under normal circumstances, the wear parts of equipment are surface-treated, which gives them a high surface hardness and makes them less prone to wear. However, the interior of these parts is softer. In older equipment, the surfaces of some parts are already worn, and therefore using lower-quality lubricants will accelerate the wear of those parts. We recommend not using lower-grade or inferior lubricants. III. Why can other oils not replace gear oil? Answer: In some cases, individual users have replaced gear oil with anti-wear hydraulic oil, guide rail oil, turbine oil, or ordinary machine oil. All of this is incorrect, as the power of the entire machine is transmitted through gear shifting. The meshing lines on the gear teeth are subjected to enormous loads, which requires lubricants to have extreme pressure properties; other oils, lacking extreme pressure additives, cannot provide protection for these tooth surfaces, and as a result, phenomena such as pitting and fracturing of the tooth surfaces can occur. IV. Can different types of gear oils be used interchangeably as long as their viscosity is the same? Answer: No! There are also different grades for gear oils; heavy-duty gear oils can be used as a substitute for light-duty gear oils, but the reverse is not true. At present, most domestic ordinary gear oils are of medium-duty or lower grade, and they are not suitable for use in high-speed, high-load equipment. V. What causes oil to turn white? Answer: In general, the whitening of oil is caused by water entering the fuel tank, which results in emulsification. It is necessary to prevent water from getting into the lubricant container or to stop rainwater from entering opened oil drums. In practice, the equipment should be checked to determine whether the oil seals are damaged; when changing the oil, it is necessary to check for water inside the tank, and the oil drums should be stored in a place protected from rain. VI. It’s not important to use lubricant; as long as the equipment has oil, that’s enough. Can just buy some from the market and use it? Answer: It is absolutely essential to pay attention to the use of lubricants. Lubricants are like blood in the human body; poor-quality lubricants can damage your expensive equipment. Different lubricants contain various additives to meet the needs of different parts of the equipment. For example, antioxidants prevent the oil from oxidizing, rust inhibitors prevent the equipment from rusting, and anti-wear agents prevent wear and tear on the equipment. VII. Can the lubricating oil that has been replaced after the expiration of its usage period be used again? Answer: It is not appropriate for some users to reuse the used oil after settling it. The various properties of oil deteriorate after use, and using such used oil is equivalent to using substandard product. VIII. When it is time to change the oil, can some of the lubricating oil be drained and then some new lubricating oil added? Answer: The oil should be drained as much as possible. Mixing used lubricant with new lubricant reduces the quality of the lubricant, which shortens its useful life. IX. How to judge the quality of lubricant by its appearance? Answer: Qualified lubricants are generally light yellow, uniform, and transparent liquids; those with higher viscosity have a slightly darker color. (This phenomenon generally occurs only when the viscosity is above 460#.) If the oil turns black, contains impurities, or has water in it, it can be considered low-quality lubricating oil. For high-end equipment, it is essential to use lubricants produced by reputable brands from established lubricant manufacturers. Products without a brand name hardly offer any quality assurance, and there are many fake lubricants on the market, so this issue must be taken seriously. X. How to select alternative oils for imported equipment? Answer: Imported equipment usually comes with recommended products; for convenience or cost reasons, it is possible to find alternative products domestically, but care must be taken to select the right model. Some lubricants have specific requirements, so it is advisable to consult a professional lubricant supplier. XI. As long as the oil is changed frequently, can substandard lubricant be used? Answer: No, low-grade lubricants will damage the friction surfaces of the frictioning parts. Once the hard layer on these parts is damaged, wear increases, and this damage cannot be repaired. The damaged surface becomes rougher, which further leads to wear, creating a vicious cycle. XII. What does lubricant viscosity mean? Answer: Simply put, the viscosity of lubricating oil is the speed at which it flows under certain conditions; this viscosity changes with temperature. Currently, internationally, the viscosity at 40°C or 100°C is used as a standard. 13. Does high viscosity of lubricating oil indicate good quality? Answer: No! Under normal circumstances, when the operating speed of a component is high, the load on its surface is likely to be lower, resulting in a lower viscosity for the lubricant suitable for use (e.g., spindle oil); conversely, if the operating speed is low, the viscosity of the appropriate lubricant is higher (e.g., gear oil). Of course, in the end it is necessary to follow the equipment supplier’s specifications regarding the choice of lubricant. The quality of a lubricant depends on many factors beyond just its viscosity; therefore, viscosity alone cannot be used to assess the quality of a lubricant. 14. What causes foaming of lubricating oil during equipment operation? Answer: It is generally due to a quality issue with the lubricant; qualified lubricants should not produce excessive foam during use, and users should avoid using lubricants that cause foam. Another possible reason is that mixing oils can cause foam; therefore, care should be taken to avoid mixing lubricants with different properties. 15. How is lubricating oil produced? Answer: Lubricating oil is produced by refining base oil derived from petroleum and then adding various additives to it. Therefore, high-quality base oils and additives are essential for producing high-quality lubricants. 16. What does the grade of a lubricant mean? Answer: According to ISO standards, industrial lubricants are classified into various viscosity grades based on their viscosity measured at 40°C. The higher the value, the greater the viscosity; therefore, the grade of a lubricant indicates its viscosity level. 17. Why do lubricants with the same grade number have different viscosities? Answer: Each viscosity grade of lubricant has a specific range for its viscosity (which corresponds to the tolerance band in mechanical processing), typically ±10%. For example, the viscosity range for 100# gear oil is 90–110, while that for 150# gear oil is 135–165; any value within these ranges is considered acceptable. 18. What does viscosity index mean? Answer: The viscosity of any lubricant changes with temperature. The viscosity index is a value that indicates the rate at which the viscosity of an oil changes with temperature; the higher the viscosity index, the smaller the change in viscosity due to temperature. The viscosity index of industrial lubricants is generally 90 or higher. 19. After the running-in period of new equipment, is it necessary to change the lubricating oil? Answer: The lubricant must be replaced! This is because, during the initial operation of new equipment, a large number of metal particles are generated in the lubricating oil, and these particles in turn accelerate the wear of the components. 20. Why do new machines have a running-in period, and can inferior oil be used during this period? Answer: Under normal circumstances, in the initial stage of use, new machines suffer from uneven stress distribution during the mating of their components, as it is not possible to achieve 100% precision in the machining of these components. This leads to some wear, which is what is known as running-in wear. Based on experience, most equipment suppliers specify a running-in period of one month. After going through the running-in period, the machine operates with a more harmonious fit between its components, resulting in smoother operation. However, since there are certain amounts of wear particles in the lubricating oil, it is necessary to replace the lubricating oil; otherwise, these wear particles will cause further wear of the machine parts, thereby shortening the service life of the equipment. Although lubricant is used only for one month during the break-in period, some users mistakenly think that since it’s only used for a month, any type of oil will do. Here, we would like to specifically remind users: never use low-quality engine oil during the running-in period. The reasons are as follows: 1. Different parts of the machine have varying requirements for lubricant; during the running-in period, the requirements for the properties of the lubricant do not decrease – on the contrary, they become even higher. During the running-in phase of machinery, due to machining errors in the parts, the surface of the parts is subjected to greater impact forces; thus, high-quality lubricating oil is needed to protect the working surfaces of the parts from damage. 2. During the running-in period, only those areas where there is poor coordination in the operation of the machine parts wear out. If the use of low-quality lubricant causes excessive wear on the surface of the parts, it will **reduce the equipment’s lifespan**: 3. Generally, parts undergo surface heat treatment, resulting in higher hardness on their surfaces and lower hardness inside. If the use of inferior lubricant damages the hard layer on the surface of these parts, it will lead to rapid wear of those parts. 4. Wear damage is irreversible; once wear occurs, it cannot be repaired, and the parts must be replaced. In summary, use good-quality oil during the break-in period, and change the oil in a timely manner after that period! 21. Is part wear mainly due to issues with part processing or material, with lubricant playing a secondary role? Answer: No! Part wear is related to the material of the parts, machining precision, and heat treatment; however, proper use of lubricants is equally important! With the same equipment, some users have a longer usage period than others; some experience a higher rate of part replacements while others have a lower rate. This is directly related to the quality of the lubricant used. 22. Is the lifespan of oil seals related to the lubricating oil used? Answer: The lifespan of an oil seal is directly related to the use of lubricating oil! Some users have found that the oil seals on their equipment fail within just half a year of operation. The use of low-quality lubricants is one of the main causes of seal damage; such lubricants have poor anti-wear properties, which leads to wear between the shafts, bearing shells, and holes. This results in an increase in the gaps between the components, causing lateral vibration of the shaft. Under such unstable operating conditions, the oil seals are damaged very quickly, and this damage is irreversible. Using new oil seals on worn-out components also leads to rapid damage to those seals. Therefore, it is essential to use high-quality lubricants. 23. How to determine the quality of lubricating oil? Answer: Lubricating oil is akin to the blood of machinery and equipment. High-quality lubricating oil enables machines to operate smoothly; conversely, using inferior lubricating oil is like causing “blood cancer” in machines, leading to irreversible wear and tear on their components and a shortened lifespan of the machines. Therefore, it is very important to use high-quality lubricant. There is a wide variety of lubricants available on the market, and a certain proportion of fake and low-quality lubricants are present there. Purchasing inferior lubricants can cause significant losses to users. Generally, there are three main approaches to selecting lubricants: 1. Purchase lubricants from brands recommended by the equipment supplier. 2. Make purchases based on recommendations from users of similar equipment (peers in the same industry). 3. Purchase lubricants based on the user’s own experience. How can one tell the quality of the lubricating oil being purchased? Here are some tips for reference: 1) Pay attention to whether the product has a brand name and whether its origin is legitimate. Be sure not to buy any products without a brand. 2) Insert a thin tube (e.g., a stainless steel tube) to the bottom of the drum to draw out an oil sample. Observe whether the sample contains any impurities, moisture, or appears cloudy; if so, the lubricating oil product is considered substandard. 3) Judge based on experience whether the lubricant viscosity is accurate. The following are some experiences gained by users in observing and assessing the condition of lubricating oil during use: ▲ Abnormally high temperature of the lubricating oil: This may be due to poor anti-wear properties of the lubricating oil, or the presence of external heat sources. ▲ Lubricating oil turning white: This is generally caused by water getting into the oil tank. ▲ Lubricating oil turns black: 1. External impurities enter the oil tank. 2. Degradation of oil. 3. The oil change interval has been exceeded. 4. Wear of machine parts. Part wear may be caused by poor quality of lubricant, or it could be due to issues with equipment maintenance. Please check the worn parts. If a large number of parts are worn, it is generally indicative of a problem with the quality of the lubricant. If only some of the similar parts are worn while most remain intact, then it is necessary to determine whether the lubricant flow is unobstructed and whether the lubricant reaches all the friction areas. If some friction components lack lubricant, those areas will wear out, and the lubricant will also turn black. Qualified lubricants should ensure that the equipment suffers minimal wear during the oil change interval; inferior lubricants cause extensive damage to machinery, so be sure to choose high-quality lubricants.