Research Of Power Supply Equipment For Plasma Arc Surface Hardening

The plasma arc surface hardening is a method of surface heating. It is a process that material surface is quickly heated by high energy density plasma arc to cause the phase change, to form hardening zone of the martensite. Hardness and wearing resistance of parts are increased by the surface hardening technology and the interior of parts has better toughness. Compared with induction heat, blaze heat and laser surface hardening, the plasma arc hardening technology has some advantages such as simple structure, small volumes, easy manipulation, economy, and high heat efficiency. In developed industry countries, the plasma arc surface hardening has come into practical application stage. The domestic study of the plasma arc hardening technology and equipment has gained some excellent achievement, but few has been put into application. Therefore, the industrializations of plasma arc surface hardening technology will have prominent economic profit and society benefits.Due to the change of the technology parameters (spout and tungsten electrode of plasma gun burn etc.), the stability of hardening is usually affected in the practical production. Based on these problems, this paper stress on practically solution several facets:(1) Establish a power-supply system of plasma arc surface hardening which is controlled by computer, during hardening process this system real-time check and control voltage, electric current and the output status of energy.(2) This paper adopt PLC as core control unit, PLC connect with computer, use MGCS configuration software to gather the voltage and current signal during the hardening process, and then process data with MATLAB, so as to get the curve of voltage and current during hardening. After we research the main energy parameters of hardening process, we accumulate many experiences to develop integrated intelligent and special plasma arc surface hardening power supply.(3) In order to verify the stability of this hardening system, and according to the needs of practical research item, we deal with 45,40Cr, 35CrMo, 45Mn, and 38CrSi in our experiments.Practice proved that this system is more stable, the technology practicability is better. It sets up the foundation to establish expert system of plasma arc surface hardening.