Determination of flash point of quenching oil
Quenching oil is a kind of industrial lubricating oil. Generally, it is said that the flash point is in the industrial lubricating oil, and there is little about the ignition point! Flash point is an important index of fire hazard of petroleum products. It is defined as the minimum fuel temperature when the combustible gas emitted by the oil heated in the container with specified structure is mixed with the air near the liquid level and can be ignited by Mars when reaching a certain concentration. If the flash point is below 45 ℃, it is flammable, and if the flash point is above 45 ℃, it is flammable! It is generally believed that the flash point is 20-30 ℃ higher than the service temperature! As the quenching process requires high working temperature, the quenching oil must have high flash point, otherwise it is very dangerous!
The open flash point is used for quenching oil, and the closed flash point is generally 10-40 ℃ lower than the open flash point. Open flash point: when the oil is heated under standard conditions, the steam of the oil is in contact with the mixture of air and open fire, the temperature at which the fire starts to flash and goes out immediately is called flash point. Flash point is a safety index of heat treatment oil. Since the quenching oil is in direct contact with red hot workpiece and air (non protective atmosphere quenching), the maximum service temperature of heat treatment oil in China should be at least 80 ℃ lower than the open flash point, so as to ensure the safety of quenching process.
The flash point of quenching oil is measured according to the method of GB / t3536. Sh106b full-automatic open flash point instrument (produced by Shandong Shengtai Instrument Co., Ltd.) is designed and manufactured according to the requirements of the people's Republic of China Standard GB / T 3536 determination of flash point and ignition point of petroleum products (Cleveland open cup method).