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Forging 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 shape and size

The external dimensions of general forgings are tested using measuring tools such as steel rulers, calipers, and templates; Complex shaped die forgings can be accurately inspected using the marking method.

(2) Surface quality

If there are cracks, indentations, or folding defects on the surface of forgings, they can generally be detected with the naked eye. Sometimes when the crack is very small and the depth of the fold is unknown, it can be observed after cleaning the shovel; 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, the macroscopic structure on the forging section can be inspected with the naked eye or with a 10-30 times magnifying glass. 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 the distribution of forging flow lines, cracks, and inclusions.

(4) Metallographic examination

The inspection method of observing the microstructure of forgings using a metallographic microscope can examine items such as carbide distribution, grain size, and decarburization depth.

(5) Mechanical properties

The mechanical performance testing items mainly include hardness, tensile strength, and impact toughness. Sometimes, according to the design requirements of the parts, cold bending tests, fatigue tests, etc. can also be carried out.

The above quality inspection items are sometimes used separately based on design requirements and actual production conditions, sometimes inspected piece by piece, and sometimes sampled for each batch of forgings. By conducting quality inspections, it is possible to assess whether the forgings are qualified. For defective forgings, the causes should be analyzed and preventive measures should be proposed.