The existence of forging defects, some will affect the quality of subsequent processing or processing quality, and some seriously affect the performance and use of forgings, and even greatly reduce the service life of the finished products, endangering safety. Therefore, in order to ensure or improve the quality of forgings, in addition to strengthening the quality control in the process, take corresponding measures to prevent the occurrence of forging defects, and also carry out the necessary quality inspection to prevent the subsequent processes (such as heat treatment, surface treatment, cold processing) And forgings using a defect that has a bad influence on performance. After the quality inspection, it is also possible to take remedial measures against the forged parts according to the nature of the defects and the degree of use, so that they meet the technical standards or requirements for use.
Therefore, the quality inspection of forgings is in a sense, on the one hand, the quality of the forged parts, and on the other hand, the improvement direction of the forging process, so as to ensure that the forging quality meets the requirements of the forging technical standards and meets the design, Processing and use requirements.
Inspection of forging quality includes inspection of appearance quality and internal quality. The appearance quality inspection mainly refers to the inspection of the geometrical dimensions, shape and surface condition of the forgings; the inspection of the internal quality mainly refers to the inspection of the chemical composition, macroscopic structure, microstructure and mechanical properties of the forgings.
Specifically, the appearance quality inspection of the forgings is to check whether the shape and geometrical dimensions of the forgings conform to the specifications of the drawings, whether the surfaces of the forgings are defective, what are the defects of the nature, and what are their morphological characteristics. The inspection of the surface state is generally to check whether the surface of the forging has surface cracks, folds, wrinkles, craters, orange peel, blistering, plaque, corrosion pits, bumps, foreign objects, underfill, pits, lack of meat, stroke Defects such as marks. The internal quality inspection is to check the intrinsic quality of the forging itself. It is a quality condition that cannot be found in the appearance quality inspection. It includes both checking the internal defects of the forgings and checking the mechanical properties of the forgings, while for important parts, key parts or large forgings. Chemical composition analysis should also be performed. For internal defects, we will verify the forgings such as internal cracks, shrinkage cavities, loose, coarse crystals, white spots, dendrites, flow lines that do not conform to the shape, and streamline disturbances by low-inspection, fracture inspection, and high-inspection. , through flow, coarse crystal ring, oxide film, delamination, overheating, burnt tissue and other defects. For the mechanical properties, the tensile strength, plasticity, toughness, hardness, fatigue strength, high-temperature instantaneous breaking strength, high-temperature permanent strength, long-lasting plasticity and high-temperature creep strength are examined.
Since the forgings are made into parts, the materials used and the working conditions are different during the use, and the materials and metallurgical processes are different. Therefore, the different parts are classified according to the above conditions and according to the requirements of the department. Different departments and different standards have different classifications for forgings. However, no matter how the forging quality inspection is inseparable from the two major types of inspection, namely the appearance quality and the internal quality inspection, but the types of forgings are different, and the specific inspection items, inspection quantity and inspection requirements are different. . For example, some industrial departments divide structural steel, stainless steel, and heat-resistant steel forgings into Class IV for inspection. Some departments divide aluminum alloy forgings and die forgings into Class III for inspection according to their use, and other departments will use aluminum alloys. Copper alloy forgings are classified into Class IV for inspection.
The inspection of forging quality has the nature of sampling except for individual items of individual categories. The sampling inspection is qualified, indicating that the forgings of the entire acceptance batch meet the requirements. For some types of forgings, the non-inspection items are stipulated, and these items of the forgings cannot be considered as not controlled, but the corresponding quality assurance measures are taken in the production, such as the raw material re-inspection system, the forging forming system, Regular inspection system, process discipline inspection system and reasonable group approval, etc., so as to simplify the inspection process and ensure the use requirements under the premise of guaranteeing the quality of forgings.
In short, the content of forging quality inspection involves a wide range of projects, and there are many projects. In actual work, the quality of forgings should be tested according to the requirements of the design and the items required by the technical materials.
Therefore, the quality inspection of forgings is in a sense, on the one hand, the quality of the forged parts, and on the other hand, the improvement direction of the forging process, so as to ensure that the forging quality meets the requirements of the forging technical standards and meets the design, Processing and use requirements.
Inspection of forging quality includes inspection of appearance quality and internal quality. The appearance quality inspection mainly refers to the inspection of the geometrical dimensions, shape and surface condition of the forgings; the inspection of the internal quality mainly refers to the inspection of the chemical composition, macroscopic structure, microstructure and mechanical properties of the forgings.
Specifically, the appearance quality inspection of the forgings is to check whether the shape and geometrical dimensions of the forgings conform to the specifications of the drawings, whether the surfaces of the forgings are defective, what are the defects of the nature, and what are their morphological characteristics. The inspection of the surface state is generally to check whether the surface of the forging has surface cracks, folds, wrinkles, craters, orange peel, blistering, plaque, corrosion pits, bumps, foreign objects, underfill, pits, lack of meat, stroke Defects such as marks. The internal quality inspection is to check the intrinsic quality of the forging itself. It is a quality condition that cannot be found in the appearance quality inspection. It includes both checking the internal defects of the forgings and checking the mechanical properties of the forgings, while for important parts, key parts or large forgings. Chemical composition analysis should also be performed. For internal defects, we will verify the forgings such as internal cracks, shrinkage cavities, loose, coarse crystals, white spots, dendrites, flow lines that do not conform to the shape, and streamline disturbances by low-inspection, fracture inspection, and high-inspection. , through flow, coarse crystal ring, oxide film, delamination, overheating, burnt tissue and other defects. For the mechanical properties, the tensile strength, plasticity, toughness, hardness, fatigue strength, high-temperature instantaneous breaking strength, high-temperature permanent strength, long-lasting plasticity and high-temperature creep strength are examined.
Since the forgings are made into parts, the materials used and the working conditions are different during the use, and the materials and metallurgical processes are different. Therefore, the different parts are classified according to the above conditions and according to the requirements of the department. Different departments and different standards have different classifications for forgings. However, no matter how the forging quality inspection is inseparable from the two major types of inspection, namely the appearance quality and the internal quality inspection, but the types of forgings are different, and the specific inspection items, inspection quantity and inspection requirements are different. . For example, some industrial departments divide structural steel, stainless steel, and heat-resistant steel forgings into Class IV for inspection. Some departments divide aluminum alloy forgings and die forgings into Class III for inspection according to their use, and other departments will use aluminum alloys. Copper alloy forgings are classified into Class IV for inspection.
The inspection of forging quality has the nature of sampling except for individual items of individual categories. The sampling inspection is qualified, indicating that the forgings of the entire acceptance batch meet the requirements. For some types of forgings, the non-inspection items are stipulated, and these items of the forgings cannot be considered as not controlled, but the corresponding quality assurance measures are taken in the production, such as the raw material re-inspection system, the forging forming system, Regular inspection system, process discipline inspection system and reasonable group approval, etc., so as to simplify the inspection process and ensure the use requirements under the premise of guaranteeing the quality of forgings.
In short, the content of forging quality inspection involves a wide range of projects, and there are many projects. In actual work, the quality of forgings should be tested according to the requirements of the design and the items required by the technical materials.
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