In the use of the change gear quenching medium

by:Hengyang Furnace     2021-01-09
Whether quenching oil or water soluble quenchant, they are in use to contact heat artifacts, also will be different levels of pollution. Into the air, the medium will be oxidized. High temperature may cause the thermal decomposition of organic medium, such as oxidation and polymerization reaction. Pollution may make medium more complex oxide and other changes. All these changes and their changes in medium products will cause the medium metamorphism. The color change of the quenching oil changes, transparency, viscosity and so on all is usually the sign of deterioration. Ought to say, there is no the same medium. We care about only three points: 1, is the impact of changes on medium cooling characteristics. 2, how is bad. 3, is to use any way to get to know and correct bad impact, to ensure the long-term stability of quenching quality. Talked about earlier, water soluble quenchant is mainly used to reduce the low temperature of water cooling speed. And water-soluble quenching liquid in the use of the change trend is the opposite, change the low temperature cooling rate increase gradually, in an attempt to restore to the point of without before hardening agent. Ordinary oil change trend in the use simple said is at the beginning of the low temperature cooling rate gradually reduced, steam membrane phase gradually reduces with the cooling speed of high temperature stage in slightly increased. Use time growth, further increased due to the oil viscosity, oil, high temperature and cooling speed will be slow, the workpiece cooling effect is obvious. Special quenching oil changes in the use of more complex, it contains the change of the doping and base oil changes in two parts, is the comprehensive results of these two aspects. Different quenching oil and different using conditions, the changes will have a larger difference. It should be pointed out that under the condition of not affected by water pollution, almost all of the special quenching oil after long-term use of low temperature cooling speed will slow down gradually. When using time is longer, the workpiece quenching effect will be obvious. Oil has good stability, metamorphic slowly; The stability of the oil is poor, metamorphic quickly. The use of oil temperature is higher, the faster oil deterioration. Equipped with circulation cooling system, make the oil temperature stability in the appropriate range, and through the cycle of groove mixing measures to prevent local overheating can slow down oil deterioration rate, prolong the service life of oil. Metamorphism of different medium speed in addition to the variety and quality of the influence by the medium, the influence factors of there is a common, that is the same period, the greater the amount of quenching workpiece, quenching liquid metamorphism is more serious. In many cases, the amount of quenching workpiece should be mentioned here that has total surface area of the quenching workpiece. Artifacts is smaller, the greater the total surface area of the same weight, the more quenching medium metamorphism. Management problem is also the major problems affecting gear quenching quality can not be ignored. Besides should strictly according to the process operation, the management of quenching medium, especially important to prevent pollution. Quenching oil emulsion to sneak into the water, water in oil, tend to cause the quenching hardness or inadequate quenching cracking. Instead, PAG quenching liquid in oil emulsion into the sometimes can also cause cracking. The change of the respect such as colour, transparency of quenching medium can reflect its bad situation. Measurement of quench oil viscosity, flash point, the change of carbon residue, acid value, etc can also determine the degree of metamorphism. In the impact of metamorphism, and the largest workpiece heat treatment effect relationship is cooling characteristics change. In order to ensure that the gear quenching cooling effect, suggest to use cooling characteristics of quenching oil and quenching medium is regularly detection, and manage the cooling characteristics of medium, general small plant is not necessary to provide cooling characteristics tester, can go to the unit is equipped with the instrument to measure. Quenching medium production units shall be carried out in a factory for the user of this test. Determination of cooling characteristics of quenching medium, it is best to use in line with international standards ( ISO9950) The cooling characteristics of the instrument. Analysis of the cooling medium characteristics should see the cooling rate of medium distribution, rather than looking at the highest cooling speed value. The highest cooling speed is the same, or to 300 ℃ of cooling time of the same medium, cooling velocity distribution is different, because they their heat treatment effect can have very big difference. It has already been simple when it comes to medium cooling velocity distribution characteristics and its cooling effect, the relationship between the details can see resources later in this article [ 5] 。 Record in long-term production of similar workpiece quenching hardness, depth of hardening and quenching distortion, analysis their change trend, enables us to understand the changing rule of the cooling characteristics of quenching media. With these records, can not only help us to control the cooling performance of the medium, cause the heat treatment can also help you analysis the cause of the accident, so as to solve the quality problems in a timely manner. When it comes to front, medium metamorphism is inevitable.
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