The technical background of the blackening furnace and its operation precautions

The technical background of the blackening furnace and its operation precautions

Technical background of the blackening furnace:

Blackening furnace is a furnace body that heat-treats powder metallurgy workpieces to blacken the surface of the workpiece to form a protective layer. It includes furnace cover, furnace wall and base. The furnace cover, furnace wall and base are enclosed to accommodate the workpiece to be heat-treated The furnace cavity, the furnace cover is hinged on the top of the furnace wall, the furnace cover is provided with a plurality of holes for screws to pass through, the top of the furnace wall is provided with threaded holes corresponding to the holes on the furnace cover, and the lower surface of the furnace cover is fixed Seal ring.

When it is necessary to close the furnace cover to heat the workpiece, cover the opening of the furnace chamber with the furnace cover, and lock the furnace cover with the screw passing through the hole of the furnace cover and tighten the screw hole of the furnace wall; the furnace cover needs to be opened to take and put When working with the workpiece, loosen the screw and open the furnace cover.

Since the furnace cover of the blackening furnace in the prior art is manually opened and closed and then locked by screws, the following drawbacks exist every time the furnace cover is opened or closed, the screws need to be manually tightened or loosened, which is troublesome, time-consuming and laborious. Moreover, the more important thing is that the furnace cover is locked by screws, and its sealing effect is very poor, which causes the pressure in the furnace cavity to be unable to increase, generally only about 0.3 bar, heat treatment under lower air pressure For the workpiece, the thickness of the blackened layer is small and uneven, and the blackened heat treatment effect is not ideal.

Notes on the operation of the blackening furnace:

1. Wear protective equipment during operation.

2. When configuring the bluing solution, first add 2/3 of the volume of water in the bluing tank, put the required amount of NaOH into the metal basket, and then hang into the liquid surface, do not enter all, let the NaOH slowly melt into the water.

3. In the bluing process, after each process of degreasing, pickling and bluing, there must be a cleaning process to prevent the residual liquid from the upper process from being carried into the tank of the next process.

4. For plane workpieces, try to avoid the plane contact of the workpiece, which will affect the blackening film thickness, and use the workpiece hoisting method when necessary.

5. For the rework of the workpiece that has completed the oiling process, it is necessary to start with degreasing; for the workpiece without oiling, it is enough to start from the pickling process.

6. During continuous production, the bluing tank liquid should be cleaned once a week.