Fastener tensile test
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Has anyone who has done tensile testing on fasteners? Can fasteners of similar specifications that were produced in the same furnace and batch be combined together, so that sampling can be carried out on a proportional basis? This would allow for a reduction in the number of samples required; experienced personnel can discuss this matter
I remember that there are also standards for sampling product inspection. I don’t know much about this; I’ll wait for experts to explain it
1. There are corresponding **standards** for the inspection of commercial-grade fasteners. 2. For specialty-grade fasteners, they are inspected in batches, with a maximum of 3,000 studs per batch. 3. For example, the requirements for batch testing of high- and medium-temperature double-headed studs used in the petrochemical industry are as follows: 3.1. Parts with the same furnace batch number, the same specifications, the same forging process, and the same heat treatment process are grouped together into one batch. 3.2. Each batch must contain at least 2 blanks for mechanical property testing. 3.3. At a radius of 1/2 (with the smaller value taken from the core), 1 tensile test sample and 3 impact test samples are cut from each blank along the axial direction. 3.4. If the test results are unsatisfactory, additional random inspections should be conducted; if those tests are also unsatisfactory, reheat treatment is required. 4. Additional notes on batch grouping: When the bolt length is 100 mm or less, a difference of 25 mm in length can be considered as belonging to the same batch ； When the bolt length is greater than 100 mm, lengths differing by 50 mm can be considered part of the same batch