brazing characteristics(1) low temperature brazing, the joint is smooth, small changes in structure and mechanical properties, deformation, precise size of the workpiece.(2) the dissimilar metal welding, dissimilar materials can also be welded, and the difference in thickness of the workpiece is not critical.(3) Some welding Brazing Alloys method can simultaneously multiple weldments, multi-joint, high productivity.(4) brazing equipment is simple, low investment costs.(5) The joint strength is low, the heat resistance is poor, and the whole Qing demanding welding, brazing expensive.