Detailed explanation of the testing locations for the mechanical and chemical properties of forgings
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1 Locations for mechanical property testing 1) Take longitudinal specimens along the direction of the principal stress in the part； Take longitudinal, transverse, and vertical specimens from the high-stress areas of the parts ； 2) Parts where metal flow lines are required ； 3) The part with the smallest forging deformation ； 4) The area near the riser end of the ingot ； 5) Within the cross-section of the forging, circular solid parts are generally cut at a distance of 1/3 of the radius from the surface ； A rectangular solid is cut at a point 1/6 of the diagonal from the surface ； Hollow parts are cut at 1/2 wall thickness. 2 Sites for low-magnification microstructural inspection: 1) Cut flow line test specimens from areas where metal flow lines are required, or from cross-sections that best reflect the proper direction of metal flow ； 2) The transverse low-magnification test specimen should be taken at the largest cross-section possible ； 3) The longitudinal low-magnification test specimen should be taken from the cross-section of the part’s main axis ； 4) For forgings formed by direct forging from ingots, their low-magnification test pieces should be taken from the end near the riser ； 3 Low-magnification fracture inspection area 1) Cut test specimens from the areas of the forging where overheating is likely to occur ； 2) Cut test pieces from the part of the forging where the deformation is minimal ； 3) Under normal circumstances, the fracture can be examined on a transverse low-magnification specimen. 4 Microstructural inspection locations: 1) The largest cross-section of the forging (to check for non-metallic inclusions and grain size). 2) Areas of high stress in the part (to check for inclusions, grain size, and overheating). 3) Areas where the forging is most deformed and where temperature rise is greatest (to check for overheating and grain size). 4) For aluminum alloy forgings, to detect overheating and overburning, samples should be taken from their smallest cross-sections near the surface. 5 Non-destructive testing locations: Non-destructive testing is carried out on free-forged parts, primarily using ultrasonic testing; for some forgings, non-destructive testing methods such as fluorescent penetrant testing, magnetic particle testing, and X-ray testing can also be used after rough machining. Ultrasonic inspection is divided into full inspection and zone inspection. Zone testing involves using standards with different sensitivity levels to test various sections of the forging. The division of areas shall meet the requirements of the part drawing, and corresponding provisions shall be made in the forging drawing.
The locations for testing mechanical properties mainly include the following aspects: 1) Based on the stress conditions of the part and the requirements regarding metal flow lines, samples are taken in the longitudinal, transverse, and vertical directions at various locations. Especially in the high-stress areas of the parts, it is necessary to take specimens from multiple directions in order to comprehensively evaluate their mechanical properties. 2) Generally, the parts with the smallest forging deformation are more prone to defects; therefore, mechanical property tests are also required on these parts. 3) The area near the riser end of the steel ingot is often affected by uneven cooling, which can lead to uneven deformation or defects; therefore, it requires special attention and inspection. 4) For circular solid parts, specimens are usually cut at a distance of 1/3 of the radius from the surface ； For rectangular solid pieces, specimens are usually cut at a distance of 1/6 of the diagonal from the surface ； For hollow parts, specimens are cut at 1/2 of the wall thickness. The main areas for low-magnification tissue examination include the following: 1) Specimens for streamline inspection are taken from the areas where metal flow patterns are required or where the optimal direction of metal flow can be best reflected. 2) To gain a more comprehensive understanding of the microstructure of the part, transverse low-magnification specimens should be taken at the largest cross-section as possible. 3) The longitudinal low-magnification test specimen should be taken from the cross-section of the part’s main axis to reflect the microstructure of the entire part. 4) For forgings formed directly by forging steel ingots, their low-magnification test pieces should be cut from the section near the riser end. The main areas for low-magnification fracture inspection include the following: 1) Specimens are taken from areas of the forging where overheating is likely to occur, in order to evaluate their fracture properties. 2) Test pieces are cut from the part of the forging with the smallest deformation, in order to observe the fracture morphology and determine whether any defects are present. 3) Under normal circumstances, fracture inspection can be carried out on transverse low-magnification specimens. The main areas for microstructure inspection include the following: 1) Inspection is carried out at the largest cross-section of the forging to evaluate properties such as non-metallic inclusions and grain size. 2) Inspections are carried out on the high-stress areas of the parts to assess inclusions, grain size, and overheating. 3) Inspections are carried out at the areas where the deformation of the forging is most severe and the temperature rise is greatest, in order to evaluate properties such as overheating and grain size. 4) For aluminum alloy forgings, samples should be taken from the area with the smallest cross-section and near the surface in order to assess whether overheating or overburning has occurred. The areas to be inspected using non-destructive testing methods are determined based on specific circumstances. Common non-destructive testing methods include ultrasonic testing, fluorescent penetrant testing, magnetic particle testing, X-rays, and others. For free-forged parts, ultrasonic testing is generally used for comprehensive inspection or sectional inspection. Zone testing requires using standards with different sensitivity levels at various locations, in accordance with the requirements specified in the part drawing. .
These inspection requirements are generally specified in the \"technical specifications\" for the pattern, and manufacturers should conduct inspections strictly in accordance with these requirements.