Identification and Selection of High Temperature Chain Oil Performance and Quality for Coating (Spraying) Production Line
September 01, 2023
A chain is a flexible transmission component that transmits motion and power through the meshing and detachment of its links and sprocket teeth. There are many types of chains, but the most commonly used is sleeve roller chains. The sleeve roller chain has two rotating friction pairs, one is the sleeve and the pin shaft, and the other is the sleeve and the roller. The difficulty of chain lubrication is due to the small fitting clearance, which makes it difficult for lubricants to enter. The lubrication key point of the chain is between the hub and shaft, which is also the most prone area to wear and tear, which can cause the chain to elongate;
According to the regulations of the chain manufacturer, when the removal length of the chain link exceeds 5% of the total length, the chain is scrapped; A chain without proper lubrication has a lifespan of no more than 5 years, and a well lubricated chain can work for 15-20 years. Analysis of Chain Lubrication Requirements Chain lubrication points: The chain oil used here should meet the following requirements: (1) Friction and wear characteristics: When the chain is working, rolling friction and sliding friction occur. The guide wheel is actually equivalent to a rolling bearing, with low speed and medium load; At the connecting parts of each chain link, sliding friction occurs between the two ends of the side plate, the connecting block, and the pin. When the chain turns, the pin rotates in the pin hole, causing severe friction. Therefore, the pin determines the length of the chain's service life; The requirements for lubricants based on the above friction and wear characteristics are: 1) Good adhesion, able to firmly adhere to the friction surface without being shaken off by the centrifugal force of the chain 2) Having good lubrication performance and extreme pressure resistance, reducing friction and wear; 3) Good permeability, able to penetrate into various friction links of the chain link, forming an oil film; Due to the small fit gap between the pin and the pin hole, it is difficult for ordinary lubricants to reach the friction surface. Therefore, this is the key to chain lubrication technology. (2) Requirements for lubrication in high-temperature environments: After the surface of the workpiece is painted, it needs to enter the oven for baking, which means that the hanging conveyor chain needs to repeatedly enter the high temperature zone, and each time it enters the high temperature zone, it takes about dozens of minutes. This requires that the lubricant used for the chain should meet the following requirements: 1) The Base Oil of lubricants has a suitable viscosity and a high viscosity index; 2) Flash point>270 ℃, below 230 ℃ at high temperatures, without carbon deposition and less volatile; 3) Good oxidation stability. Lubricants come into contact with air in high temperature environments and do not quickly oxidize to form oxides. (3) Requirements for lubrication in high humidity, acid-base environments: 1) Resistant to water and moisture, lubricants do not emulsify or dissolve in water; 2) Resistant to acid and alkali chemical corrosion, especially the reaction of phosphorus chemicals; 3) Rust prevention and anti-corrosion performance,; (4) Requirements for long-term lubrication: Considering the heavy production tasks on the production line, the time required for equipment maintenance should be minimized as much as possible, and lubricants should have long-term effectiveness; Alternatively, consider convenient and feasible filling methods (5) Types of Conventional Chain Lubricants
In practical use, products will gradually expose a series of problems such as poor viscosity and temperature, inability to balance high and low temperatures, high volatility, and easy coking and carbon deposition. Synthetic oil is a lubricating product artificially synthesized by people based on these shortcomings of mineral oil, with strong comprehensive performance and much higher performance than mineral oil products. The working cycle is extended 5-8 times compared to mineral oil.
The most commonly used synthetic oils include PAO, polyester, and polyether (PAG). They each have their own characteristics. PAG type high-temperature oils have the characteristic of instantaneous evaporation, that is, they will quickly evaporate completely at a certain temperature (usually between 200 and 240 ℃), and their evaporation rate begins to increase rapidly at 160 ℃. Therefore, the amount of these oils used in actual use is often astonishing, but the evaporation characteristics of these oils can decrease and lower chain carbon deposition at temperatures above 160 ℃. The lubricating ability of synthetic hydrocarbon oil is lower than that of PAG, and the problem of carbon deposition in hydrocarbon oil is also relatively serious, so there are not many cases of using hydrocarbon oil to lubricate chains under conditions above 160 ℃. In the application of mineral oil, the problems of lubrication and carbon deposition can be quite serious, so mineral oil lubrication should not be applied here. Ester oils can reach a usage temperature of around 200 ℃, and have good viscosity temperature characteristics, are not easy to accumulate carbon and coke, making them the most widely used in automotive coating and conveying systems.
In addition, the high-temperature chain oil of the coating line should avoid containing free silicon components. Before selecting a product, a shrinkage test should be strictly conducted to avoid causing shrinkage on the workpiece.
