The operating temperature of the oil
The permissible and recommended operating temperature range of the quenching furnace quenching oil is specified. Within the specified range, the use temperature can be determined according to the actual situation. Appropriately increasing the oil temperature can reduce the viscosity of the oil, so that the quenching cooling capacity of the oil is slightly improved. The oil temperature is too high, because the temperature difference with the workpiece is reduced, the cooling capacity will be reduced.
The oil temperature is high, and the oxidation and deterioration of oil are fast. The oil temperature is low, and the oxidation deterioration of oil is slow. The circulating cooling system of the quenching oil should be kept in good condition so that the temperature of the quenching oil can be stabilized in the required range. At the same time, in order to extend the service life of the oil, too high oil temperature should be used less.
Oil pollution and prevention
The sources of pollution of quenching oil include: external pollution, such as the oxide brought by the workpiece, the water entered by the leakage of the cooler and other substances from the outside; Self-pollution, oxidation metamorphic products left in the oil that cannot be automatically discharged during use; In addition, the residual products after the reaction of foreign pollutants with quenching oil and its pollutants.
The accumulation of internal and external pollutants will gradually change the color, transparency, viscosity, flash point, residual carbon and acid value of the oil. This change process is the metamorphic process of quenching oil. Among the effects caused by metamorphism, the relationship with the heat treatment effect of the workpiece is the change of the oil cooling characteristics and the deterioration of the brightness of the workpiece after quenching. The change of cooling characteristics often changes the quenching hardness, hardening depth and deformation of the same workpiece.
Agitation of quenching oil
Good agitation can avoid the local oil temperature is too high, so that the oil temperature in each part of the tank tends to be uniform. Agitation can increase the relative flow rate between the workpiece and the quenching oil of the quenching furnace, thereby improving the cooling capacity of the oil.
The setting of the agitation device and the mounting method of the workpiece should try to make the workpiece in different parts of the same batch of quenching obtain basically similar oil temperature. Partial workpiece or workpiece local relative flow rate is too high or too low, will have an adverse effect on the uniformity of quenching cooling. Of course, compared with water-based quenching media, the degree of this effect is much smaller.