Fri, 08 Jun 2018 02:16:09 +0000
Rapid heating and cooling technology of vacuum furnace
Vacuum tempering is the purpose of the advantage of vacuum quenching (products oxidation, decarbonization, surface light corrosion, no pollution, etc.) to keep down, at the same time, complete removal of quenching stress tempering process, reduce the deformation and cracking and perfect the technical requirements of material organization; Without vacuum tempering, the advantages of vacuum quenching will be lost. At present domestic vacuum tempering equipment and process all shortcomings, vacuum quenching after good light become grey or beige color after vacuum tempering, between corrosion phenomenon, will also bring hardness uneven, some domestic vacuum tempering furnace cooling speed slow, for some steel produced the second kind of temper brittleness danger. To sum up, hunan dingli technology thinks that the vacuum tempering technology and equipment design need to arouse the attention of heat treatment professionals.
(1) purpose of rapid heating and cooling of vacuum return furnace
Also, it can shorten the processing time and improve the equipment productivity.
Impounding saves energy and material consumption;
Resistance to temper brittleness of some materials.
(2) rapid heating design measures
In the low temperature heating stage, in order to improve the temperature uniformity and heating speed of the furnace, it is necessary to refill the gas. WZH vacuum furnace adopts 0. 06 ~ 0. 07 mpa (0. 6 x 105 ~ 0. 7 * 105Pa) recharging gas can effectively improve the heating speed of the temper workpiece and the uniformity of furnace temperature.
Parliamentary heat exchanger does not work to absorb heat, such as WZH 60 furnace will heat exchanger in the lifting position.
The wind guide plate is installed to adjust the optimal Angle to maximize the heat transfer efficiency of the airflow.
The agitator fan agitates, the airflow circulation, enhances the heating speed.
(3) rapid cooling design measures
(1) filling the positive pressure in the furnace gases, high purity N2 can be used, or the mixture (such as the volume fraction of 90% 10% N2 + H2) in order to obtain high tempering brightness surface of workpiece, filling the gas circulation by fan agitation air-cooled cooling artifacts, can effectively improve the cooling speed of tempering artifacts, inhibition of some materials of the second kind temper brittleness.
The circulating heat exchanger (descending) is in a working state, so that a large amount of heat in the flow air is carried away by the heat exchanger and the cooling speed is accelerated.
The torque guide plate adjusts the Angle of airflow direction and flow best.