Vacuum quenching furnace air circulation

Vacuum quenching furnace mainly vacuum oil quenching and vacuum gas quenching, they each have their advantages and disadvantages: look from the surface quality after quenching, vacuum oil quenching 20% ~ 30% lower than the vacuum gas quenching brightness, but also for cleaning, from the mechanical properties after quenching, high speed steel tools after vacuum oil quenching in workpiece surface formed by a white layer of residual austenite and carbide, X-ray structure analysis has proved that: the white layer is composed of a compound of carbides and residual austenite, form a composite carbide carbon is not from the remaining in the furnace atmosphere, but from the quenching oil.

In order to overcome the shortage of vacuum oil quenching, a large and in-depth study has been carried out in real air quenching, which has a deep understanding of the mechanism, characteristics and influencing factors of true air quenching. According to the analysis of the workpiece in cooling indoor heat transfer way, to learn, in the process of cooling, cycle gas in both the flow and flow at the bottom and the flow of the systemic circulation channel perpendicular, and they speed close to, because of their direction perpendicular, greatly promote the micro circulation gas molecules in the circulation flow vertically mutual diffusion and heat transfer. At the bottom of the quench cooling system distribution with multiple concentric circles centered on the center, in each of the concentric circles on the same amount of hole, because has many and dense in the center of the bottom nozzle, when the gas circulation to encounter artifacts, quickly spread to all around.

But divergent circulation gas again by two side suction effect of fluid and turbo fan itself, forcing the gas along the material at the bottom of the basket through artifacts, such not only can delay the cycle gas passes through the workpiece, and increase the heat transfer efficiency of circulating gas and the workpiece, the circulating gas as much as possible to eliminate the heat workpieces, improve the cooling speed of workpiece. The circulating gas after the workpiece has a higher temperature. Under the effect of fan, the first through the heat exchanger, and then under the guidance of the fan, along the flow channel cooling chamber, on both sides of the nozzle in the quenching cooling system under the action of reverse speed, quickly on the furnace wall heat transfer, so that further cooling of the circulating gas, finally at a relatively low temperature through the artifacts, forming a cycle.