The Study On The Organization And The Performance Of Plasma Arc Quenched Layer Of Materials Commonly Used In Piston Rod And The Cylinder Sleeve

The plasma arc case quenching is one of partial superficial modified technologies which has been developed in the recent 30 years. The plasma electric arc is one kind of heat source, the energy density of which is only inferior to the laser and the electron beam. Used in the work, piece case hardening will has a very good application prospect.Using self-made the plasma control device and the plasma arc quenching special-purpose spray gun installment, the way about plasma arc surface self-cooling quenching experiment on the materials on the C620-1 conventional lathe is introduced in this paper. On the base of original experiment data and through the microstructure analysis, hardness examination arid the wear resistant test, further study on the organization and the performance characteristic of the plasma arc case quenched layer of materials (45, 2Cr13, 17-4PH, QT600-3) which commonly used in piston rod and the cylinder sleeve on the project is carryed out,and the reason which lead to it is also analied.All the studies provide the experiment basis for the application in the realm of production.Through the scanning electricity mirror experiment of plasma arc case quenched layer, the conclusion can be drawn that: under the certain craftwork parameter, with the differences of chemistry ingredient, the obvious diversity will appear in every place of quenching zone along deepness direction. As a rule, the state of the surface layer of quenching zone is closed to laser quenching, naming crypto-crystal martensite, the morphology of which is also different. In the internal of quenching zone, the condition approaches lower energy current density quenching, and the morphology of commixture structure is different too. For 17-4PH steel, the low temperature aging is needed after plasma arc quenching (melting).Only by this way, it can be possible to obtain the highest degree of hardness and the biggest resistance to wear. The reason is that this kind of steel can be strengthened, mainly through the dissemination strengthening mechanism.Meanwhile through studying on the intercross quenching belt microstructure of 45 steel and comparing with one time quenching area, we find that the degree of hardness of crypto-crystal martensite which obtained on the intercross quenching spot (two quenching areas) is also higher, and the hardness of the entire quenching spot is not obvious suddenly fell.The result of hardness experiment indicated that the hardness of materials after plasma arc quenching (17-4PH material must be quenched and low temperature aging) is distinctly enhanced, and a obvious hardness downward gradient doesn't appear at the hardened layer. This kind of characteristic is all advantageous to the wear resistant enhancement.In addition, the wear resistant examination indicated that the relative wear resistance of each materials after plasma arc quenching is enhanced in the different kinds of degree.