This weld scanner is primarily applied to fillet weld inspection on boiler heat exchanger tube sheets, suitable for internal welds with an inner diameter of 15 mm and above. Its rotary mechanism adopts a high-efficiency drive system to enable the probe’s full circumferential rotation around the tube center for precise weld testing. The integrated drive unit combines a motor, gearbox and encoder, delivering stable power while avoiding probe cable tangling to boost inspection efficiency and operational safety.