Study On High Frequency Hammer Control System Of Electromagnetic Hammer

Welding is a permanent connection method for the weldment atoms, which is through heating or pressure, or both with, and with or without the filler metal. Fusion Welding is a process of rapid heating and cooling locally. Due to the restrict of workpiece ontology, welding zone can not expand and shrink freely, and residual welding stress and deformation is produced after cooling in weldment, which will influence bearing static load capacity, structure brittleness, fatigue strength, structural stiffness, precision and dimension stability of component. At the same time, widmanstatten structure in bead microstructure was bigger, but not enough refined, which influenced the mechanical properties of weld bead to cause inhomogeneity of metallurgical Property in the welded joint uniformity of metallurgical properties. Therefore improving the welding quality, eliminating the welding residual stress during the welding process is very necessary. At present the requirement for welding process, welding mechanization and automation level is higher and higher.At present, the methods to eliminate welding residual stress are heat treatment method, statute of limitation, vibration method and hammering method, among which, hammering method is applied more frequently. As the welding with trailing peening develop from hand hammering to automatic hammering, the automatic control device for welding trailing has been researching. But tunability and human-computer exchange is not very good,and hammering frequency is low, not meeting the different requirements for different workpiece and weldment to hammering force and hammering frequency. During the process of welding with trailing peening, with the hammering frequency increasing, the welding quality improves more obviously. The original device can only achieve the frequency for 3Hz or so and can’t meet the requirements for welding hammer to the frequency. As to this situation, choose STC12C5A60S2 microcontroller as control core, using C language program for handling keys information and welds temperature collected by temperature sensor, and using 12864 LCD showing hammer parameters to design high frequency welding hammer circuit; Using stepping motor to control the mobile location of electromagnetic hammer precisely; designing the double electromagnet organization, realizing a wider range(1 ~ 8 Hz)and high frequency hammer; devising a welding hammer walking car and testing the welding hammer installed experiment in MZ-1000 arc welding machine. The test results show that: the electromagnetic hammer control circuit is simple, reliable and realized 6 ~ 8Hz high frequency hammer blow; analyzing the weld bead microstructure of different hammering frequency: the higher the hammering frequency, the more refined themicrostructure, the more obviously the mechanical properties improve.