Abstract: The thermal extrusion punch of 3Cr2W8V is acted a pulse current. So small welded joins are formed by metal melting, the crack tip is passivation and the thermal fatigue crack is prevented from subcritical extending. The pulse current discharge can make the structure and capability of the crack tips progress, improving the energy and expansion work required when the crack burgeon in the crack tip. The thermal fatigue crack subcritical extending could be prevented.

Key words: Batten martensite, Crack tip passivation, Pulse current, Thermal fatigue crack