How to solve the problem of corruption and smell in the application of quenching agent?
July 20, 2021
At present, due to its unique advantages in environmental protection, technology and cost, polymer quenching agents have been used in more and more applications, accounting for 20% of the entire heat treatment quenching medium, and the more important and widely used PAG-polyethylene ethylene two alcohol. PAG is a neutral non-ionic polymer, a copolymer of ethylene oxide and propylene oxide. Its cooling capacity is between water and oil. The cooling capacity can be close to or slightly greater than that of water or the cooling capacity can be very close to oil. It can be a quenching medium that replaces oil with water.
However, the quenching liquid treatment is prone to decay and smelly during use. PH drop, insufficient circulation, existence of oil staining, low quality water for liquid preparation, low product quality, bacteria in the air, foreign debris, etc. are all reasons for the corruption of the quenching liquid. Unlike water and oil, polymer quenching agents are rich in organic nutrients. As we all know, life can multiply when there is water, air and nutrients, so the polymer quencher system is easy to breed bacteria. Especially if it has not been used for a long time, especially in the hot summer. There is no bactericide that can guarantee that the contaminated quenching liquid treatment will not spoil and deteriorate if it is not used for a long time. During the deterioration of the quenching solution, the growth of bacteria will reduce the pH value of the solution and may consume the anti-rust agent in the medium, thereby reducing the anti-rust performance of the solution. At the same time, it often produces unpleasant odors, which affect the working environment; and endanger the health of the operator, such as irritating the skin of the operator, which may cause dermatitis. It may also block the filter system (fungus or mold) and affect the normal operation of the system.
For the more important cooling performance of the quenching liquid treatment, the test proves that the black odor does not affect the cooling characteristics of the quenching liquid, nor does it affect the concentration measured by the refractometer, the viscosity method and the true concentration method. Whether the quenching liquid is black or smelly can not be used as an important indicator to measure the quality. The more important thing about the quenching medium is the stability of its performance. At present, the quenching liquid is mainly processed from the aspects of sterilization, pH adjustment, cleaning the system, checking the content of water bacteria in the equipment, and routine maintenance. How to maintain the quenching fluid during use? 1. When there is no quenching workpiece, it is still necessary to stir the quenching tank liquid to prevent the growth of anaerobic bacteria. It is best to stir every day. 2. It is strictly forbidden for oil stains, stolen goods, non-designated anti-rust agents and cutting fluids to enter the quenching tank, otherwise the quenching medium will age in advance. 3. Although solids such as oxide skin do not have much influence on the cooling rate, they must be removed regularly to prevent them from becoming a gathering dead zone where bacteria can breed. 4. Maintain a certain pH value of the quenching liquid. 5. Under normal pressure, the solubility of CO and CO2 gas in the medium is low, which will not have much impact on performance, but the dissolution of ammonia gas will significantly extend the vapor film stage and should be avoided.
