Abstract: To improve electrode life of resistance spot welding of aluminum alloy LF2, the deep cryogenic treatment technology of electrodes is put forward. Electrodes are treated by deep cryogenic treatment with different deep cryogenic treatment parameters. Deep cryogenic treatment electrodes life experiment is carried out and the experimenal results are compared with the non-deep cryogenic treatment electrodes life experiment ones. The properties of the deep cryogenic treatment electrodes and the non-deep cryogenic treatment electrodes are tested. The SEM area scanning and the SEM back scattering of electrodes are carried out. The grain degree of deep cryogenic treatment electrodes and the non-deep cryogenic treatment electrodes are tested by X-ray diffraction. The reason of deep cryogenic treatment improving electrode life for resistance spot welding of aluminum alloy is studied. The experimental results show that deep cryogenic treatment makes Cr, Zr in deep cryogenic treatment electrodes emanate dispersedly and makes the grain of deep cryogenic treatment electrodes smaller than non-cryogenic treatment ones, so that the electrical conductivity and the thermal conductivity of deep cryogenic treatment electrodes are improved very much , which make electrode life for spot welding aluminum alloy improve from 620 to 2 145 .

Key words: Aluminum alloy, Cryogenic treatment, Electrode life, Spot welding