Metallographic corrosive agent for super martensitic stainless steel weld grain boundary and corrosion method and application of metallographic corrosive agent

The invention discloses a metallographic corrosive agent for a super martensitic stainless steel weld grain boundary and a corrosion method and application of the metallographic corrosive agent, and belongs to the technical field of stainless steel metallographic analysis and detection. The problem that an existing metallographic corrosive agent is not clear and inaccurate in appearance of the super martensitic stainless steel weld grain boundary is solved. The metallographic corrosive agent provided by the invention is composed of CuCl2, concentrated hydrochloric acid, alcohol and deionized water according to the mass volume ratio of (1.5-2) g: (16-20) ml: 10 ml: 100 ml. The metallographic corrosive agent provided by the invention has specificity on corrosion of the grain boundary, the corroded sample surface is uniform in corrosion, the grain boundary is clear and complete, a martensite lath is not obvious, an inspector can conveniently distinguish the grain boundary, and the accuracy and efficiency of grai