Low-magnification inspection of forging raw materials. The acid leaching test is a test method to show the low structure of steel materials. In the low-magnification inspection of steel, acid leaching is one of the commonly used methods, mainly because the acid leaching test equipment is simple, easy to operate, and can clearly show various defect structures in steel materials, such as cracks, inclusions, etc. , porosity, segregation and porosity, etc., especially for forgings.

　　The acid leaching test makes use of the difference in the degree of corrosion of various parts of the steel material by the acid solution, and clearly shows the macrostructure and defects of the steel. Metallurgical quality, and then by inferring the cause of defects, take practical improvement measures in the process to achieve the purpose of improving the quality of forging products.

　　Inspection standard for acid leaching test. The requirements for the acid leaching test of the product are specified in the corresponding standards, technical conditions and agreements between the two parties.

　　Acid leaching test method. The acid leaching test is divided into hot acid leaching test method, cold acid leaching test method and electrolytic corrosion method, etc. These methods can be used in the low-magnification inspection of forgings according to different requirements. And according to its corresponding technical standards and rating standards for evaluation.

　　Hot pickling test method. The hot acid leaching test method is an inspection method that uses hot acid to corrode a low-magnification sample of a steel product to show the macrostructure and defects of the steel.

　　Cold acid leaching test method. The cold acid leaching test method is an inspection method that uses a certain proportion of acid solution to corrode low-magnification samples or forgings at room temperature to show the macrostructure and defects of steel. It is suitable for forgings that are not easy to cut low-magnification samples, some corrosion-resistant high-alloy steels and stainless steels, etc.