The selection of quenching oil and matters needing attention

Ordinary quenching oil ( The oil temperature quenching under 60 ℃) Ordinary quenching oil is mainly suitable for hardenability better iron alloy, such as a small size bearing steel, mould steel parts quenching. Previous domestic only using different type of machine oil as quenching oil. In the early 1980 s, in order to improve the cooling performance of oil products, thermal oxidation stability and rust resistance, joined the rush in the machine oil cooling agent, antioxidant and anti-rust agent, developed the different type of ordinary quenching oil, its performance is better than that of machine oil. Ordinary quenching oil can be used in the salt bath furnace, box-type furnace, pit type furnace quenching technology, generally unsuitable mixed with other oil products. When an oil change, want to clean up oil tank. Best use of the oil temperature is 50 ℃ ~ 80 ℃, the highest temperature does not exceed 80 ℃, lest affect the service life. Tank shall be installed in the mixing or oil circulation system, further improve the oil cooling ability, can make the surface cooling homogeneity, and shall regularly to add new oil tank. Bright quenching oil ( The oil temperature under 70 ℃ quenching) Bright quenching oil is parts under controlled atmosphere a cooling of quenching medium, its main characteristic is after quenching parts surface light, the main processing quenching after no longer secondary processing of small parts, such as precision instrument parts, watches and small amount of cutting tool parts. Bright quenching oil, besides can satisfy the requirement of cooling performance can prevent oxidation product of form a large micelles adhesion on surface of parts, and will have been attached on the surface of the parts, insoluble product replacement, ensure the quenching parts surface brightness. Bright quenching oil is mainly suitable for protective atmosphere furnace quenching as cooling medium, can be used for medium and small section bearing steel, die steel, cutlery steel instrument parts such as quenching, can also be used for the protective atmosphere quenching furnace processing good steel hardenability. The oil temperature at 60 ℃ ~ 80 ℃. Must control the moisture content in use, when the moisture content is more than 200 mu g/g, brightness fell sharply, must carry on the processing of quenching oil, or seriously affect the quenching quality of parts. Quick bright quenching oil ( The oil temperature under 80 ℃ quenching) Quick bright quenching oil is also used for quenching under protective atmosphere as cooling medium. It is the difference between the oil and bright quenching oil cooling speed, it is mainly used for material with poor hardenability and larger parts quenching under protective atmosphere. Quick bright quenching oil is mainly used in automobiles, tractors, bearing and protective atmosphere quenching textile machinery industry. Can be used in the automobile gear carburizing and carbonitriding, quenching, can also be used for other steel quenching under protective atmosphere when used as cooling medium, or in a protective atmosphere furnace. Use top oil temperature not over 100 ℃, ensure the product has a long-term stability of cooling capacity and good quenching brightness. It is forbidden to other oil mixed with water and a small amount of water could seriously affect the quenching parts surface state. Protective atmosphere shall be strictly controlled in the black carbon and sulfur content, it also affects the quality of the parts after quenching. Vacuum quenching oil ( The oil temperature under 80 ℃ quenching) In some special industrial department USES the general heat treatment technology can't satisfy the use requirement, the development of the vacuum heat treatment technology. Vacuum quenching oil is suitable for large and medium-sized aircraft structural steel, bearing steel and die steel and other steel quenching. Used for the first time, should be under 66 x 103 pa drainage 10 min ~ 20 min, mixed with air out in the oil, prevent due to low vacuum through mix carry air to oil in the oil in the pipeline and vacuum unit. Vacuum heat treatment process can make the workpiece no oxidation and decarburization, it does not increase carbon, reduce the deformation, can not only improve the service life of parts, and does not pollute the air, so have some special request for quenching oil: 1) Low low saturated vapor pressure of oil saturated vapor, evaporation capacity is small, in addition the evaporation capacity of oil varies with temperature and pressure, reduced pressure, temperature, evaporation will increase. Evaporation is big, easy cause pollution in furnace, vacuum effect. 2) The cooling performance is good because under the condition of vacuum heat treatment, reduced pressure, the boiling point drop, so the workpiece is easy to boil. Machining surface clean, make the film boiling stage lengthen, reducing cooling intense degrees. So pressure quenching oil in a wider range, higher cooling capacity. 3) Good light resistance and thermal stability artifacts is easy and the quenching oil of residual carbon, and sulfur, oxygen, water, acid, such as reaction, so the vacuum quenching oil to high light and thermal stability.