Research on synthetic lubricating material high temperature graphite grease
As the power of the machine is getting higher and higher, the temperature of the part where the bolt is used is getting higher and higher. If the bolt is not lubricated, the bolt will not be loosened and the machine cannot be disassembled for maintenance. According to the requirements, the drop point of the threaded grease used in this part It should be greater than 300 degrees Celsius, no high temperature loss, no pollution to other parts; at the same time, in order to ensure safety, the grease should also have flame resistance. There are many types of threaded grease at home and abroad. Generally, soft metal, metal oxide or silicate powder is added to soap-based or composite soap-based grease to resist thread scratches and seizures. For example, molybdenum disulfide, graphite and so on.
Graphite is an organic material with good extreme high temperature resistance and extreme pressure, but it is also a non-lipophilic material. It is difficult to prepare grease with graphite as a thickening agent, so grap hite has been improved. Adding lithium complex and organic bentonite to the graphite grease can indeed improve the stability of the colloid, but the dropping point of the lithium complex grease cannot reach 320°C. The consistency of graphite grease is significantly reduced after mixing, which proves that the compatibility of graphite grease with lithium complex and organic bentonite is not good.
After the study, it can be seen that: solid additives can greatly improve the thickening ability and colloidal stability of grease. The improved flake graphite uses a high-shear mixing emulsifier to cut the graphite in isooctane for 30m, but the graphite processed by this method does not achieve satisfactory results, which may be due to the gap of the shearing head reason.
The choice of base oil is also particularly important. As the base oil of thread grease, synthetic base oil should be selected. Four kinds of synthetic oils are used to make lubricating grease, and their special properties are evaluated. As the grease needs a 500℃, 2h weight loss test, it is found that the temperature filler is better during the test. We will use this material. If we find that the shortcomings will affect the quality of the grease, we will replace other materials.
The quality index of high temperature thread grease is produced after many selection tests. Grease made of more advanced solid lubricating materials is used. In order to prevent the thread from scratching and seizing, reduce the torque when the bolt is removed. In actual use, it can be disassembled freely, and the threaded button is qualified without any damage. It is necessary to add a certain solid filler. For this reason, the influence of different solid fillers on the disassembly torque is investigated, and finally grease is made according to the determined formula and technology. Only in this way can high-quality grease be produced.