Quality checks
The quality inspection items of forgings are as follows:
(1) Geometry and size
Generally, the external dimensions of forgings are tested with measuring tools such as steel rulers, calipers, and templates; Die forgings with complex shapes can be accurately inspected using the marking method.
(2) Surface quality
If there are cracks, crushes, and folding defects on the surface of the forging, they can generally be found with the naked eye. Sometimes the crack is very small, and when the fold does not know the depth, it can be observed after the shovel; If necessary, it can be inspected by flaw detection.
(3) Internal organization
Whether there are cracks, inclusions, loose and other defects inside the forging, the macroscopic structure on the forging section can be checked with the naked eye or with a 10~30 times magnifying glass. The commonly used method in production is acid etching test, that is, the sample is cut at the part of the forging that needs to be inspected, and the defects of the macroscopic structure on the section can be clearly displayed with acid erosion, such as forging streamline distribution, cracks and inclusions.
(4) Metallographic inspection
With the help of a metallographic microscope to observe the fracture microstructure of forgings, items such as carbide distribution, grain size and decarburization depth can be checked.
(5) Mechanical properties
The mechanical properties test items are mainly hardness, tensile strength and impact toughness. Sometimes, according to the design requirements of parts, it can also be used for cold bending test, fatigue test, etc.
The above quality inspection items are sometimes adopted according to the design requirements and the actual production situation, sometimes they are inspected piece by piece, and sometimes they are sampled according to each batch of forgings. Through quality checks, forgings can be assessed as qualified [7]. For defective forgings, the causes should be analyzed and measures to prevent defects should be proposed.
Grace Ma
Post time: Dec-27-2024
