How is heat transfer oil divided into high-temperature and low-temperature types?

High-temperature heat transfer oil is designed for use in certain extremely high-temperature operating environments. Its ability to handle high temperatures should be at least 28°C higher than the upper limit of the required temperature range, in order to ensure safety and prevent the oil from overheating or degrading, which would otherwise reduce its service life. Low-temperature heat transfer oil is designed as a synthetic heat transfer oil for liquid-phase heating systems operating at temperatures ranging from -75°C to 315°C, or for gas-phase heating systems at temperatures from 181°C to 315°C. It belongs to the category of both gas-phase and liquid-phase heat transfer oils; as a low-temperature heat transfer medium, it maintains a low viscosity even at extremely low temperatures, offering an optimal heat transfer coefficient in cooling media. It exhibits excellent heat transfer performance even at temperatures as low as -70°C. The differences in their components likely require checking the relevant standard — GB/T4016-83 — to see if an answer can be found.