Characteristics of plasma nitriding technology with pulsed power supply

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Compared with DC plasma nitriding, pulsed power supply has further developed the ion nitriding process and broadened the application scope on the basis of DC plasma nitriding technology. Pulse power supply plasma nitriding technology has the following characteristics:

Independent adjustable process parameters
One of the advantages of pulse power supply is that the process parameters and physical parameters can be adjusted independently. This is because under the condition of DC power supply, not only the current density requirement on the surface of parts, but also the current density requirement on the insulation of parts, both of them affect each other. Under the condition of pulse power supply, the current density is satisfied by the peak current, the insulation current is satisfied by the average current, and can be adjusted by two independent parameters. Therefore, the process parameters can be changed in a wide range.

Fast arcing speed
The output characteristic of pulse power supply has the characteristic of restraining the rapid development of arc. Because of the fast response speed of IGBT switch, it is more advantageous for us to turn off the power supply immediately when we find arc discharge, and then re-ignite the power supply. All these work are completed in tens of microseconds.

No need for blocking
Because of the suppression effect of pulse power supply on arc discharge, there is no need to plug holes for many parts, which brings great convenience to production operation. For example, when dealing with crankshaft, there is no need to plug holes, and when there are some technological holes on the crankshaft to improve the performance of parts, this advantage becomes more prominent.

Good treatment quality and small deformation are conducive to improving depth.
Because of the suppression effect of pulse power supply on arc power generation, arc light acts on the surface of parts for a very short time, so high quality surface can be obtained without burns. The uniformity of workpiece temperature is improved and the deformation of workpiece is small. Because it improves the process conditions, it can increase the depth in the same time or under the conditions that are not conducive to nitriding.

Improve the utilization rate of equipment
Under the condition of DC power supply, due to the interaction of process parameters and physical parameters, the voltage regulation range is usually about 650V during insulation, but with pulse power supply, the voltage regulation range will be increased. For example, when dealing with slits, the voltage can be increased to 900V, which increases the effective output of power supply.

Nitriding in favor of deep, narrow and microporous
Due to the suppression of the hollow cathode effect by pulse power supply, nitriding can be realized in deep holes, narrow slits and micro holes. For example, nitriding can be realized in the extrusion die of aluminium profile with cavity (≥0.6mm) and deep hole of Ф4*80 (Ф32*1030).

energy saving
Pulse power supply can effectively restrain the generation of hollow cathode effect, avoid killing arcs at small holes and narrow slots, eliminate blocking and other processes, save unnecessary auxiliary working hours, shorten the process cycle, save a lot of manpower and material resources, and improve the comprehensive utilization efficiency of equipment. In addition, the reduction of current limiting resistance in pulse power supply can also save some energy, so pulse power supply is more energy-saving than DC power supply.