Forged piece refers to a workpiece or blank obtained by forging and deforming a metal billet.
The quality inspection items for forgings are as follows:
(1) Geometric shapes and dimensions
Generally, the external dimensions of forgings are measured using measuring tools such as steel rulers, calipers, and templates; Complex shaped forged parts can be accurately inspected using the marking method.
(2) Surface quality
If there are cracks, dents, or folding defects on the surface of forgings, they can generally be detected with the naked eye. Sometimes the cracks are small and the depth of the folds is unknown, they can be observed after cleaning; If necessary, non-destructive testing can be used for inspection.
(3) Internal organization
Whether there are cracks, inclusions, looseness and other defects inside the forging can be inspected visually or with a 10-30 times magnifying glass to check the macroscopic structure on the forging section. The commonly used method in production is acid etching inspection, which involves cutting samples from the parts of the forging that need to be inspected, and etching them with acid solution to clearly display the macroscopic defects on the cross section, such as forging streamline distribution, cracks, and inclusions.
(4) Metallographic examination
The inspection method of observing the fracture microstructure of forgings with the help of metallographic microscope can check the distribution of carbides, grain size, and decarburization depth.
(5) Mechanical properties
The main mechanical performance testing items are hardness, tensile strength, and impact toughness. Sometimes, according to the design requirements of the parts, cold bending tests, fatigue tests, etc. can also be conducted.
The above quality inspection items are sometimes adopted separately according to design requirements and actual production situations, sometimes inspected piece by piece, and sometimes sampled from each batch of forgings. Through quality inspection, the qualification of forgings can be evaluated. For defective forgings, the causes should be analyzed and measures to prevent defects should be proposed.
