The HCJ-type Precision Welding Manipulator serves as a core process equipment for automatic welding in boiler, pressure vessel, pipeline, and metal structure fabrication. When integrated with roller frames and positioner/tilter systems, it forms a complete automatic welding system. This configuration enables various applications including: longitudinal/circumferential seam welding (both internal and external) for pressure vessel shells and large-diameter pipelines, joint welding of spherical/elliptical heads, overlay welding on inner walls of vessel shells and heads, as well as nozzle reinforcement area overlay welding on heads. The system demonstrates compatibility with multiple welding processes including TIG, MIG/MAG, plasma arc welding, and submerged arc welding (SAW).