Regarding the re-inspection of 15CrMoR material
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Our company manufactures two large-scale devices, using 15CrMoR as the main material. The technical specifications for device manufacturing state as follows: \"Upon receipt of the steel plates, the manufacturer shall reinspect them; the inspection includes checking the surface quality of each plate as well as the material markings on them\"； Recheck the chemical composition of the steel plate per furnace ； Inspect the mechanical properties and cold bending properties of the steel plate in accordance with the approval. What’s most unclear to me is the requirement to test the mechanical properties on a batch basis. According to Table 4 of GB713 or Table 5 of GB6654, high-temperature tensile tests are conducted once per furnace. I would like to ask experts: are high-temperature tensile tests for steel plates carried out once per furnace, or once per batch? ? The raw steel plate manufacturer has carried out high-temperature stretching on each sheet in accordance with the agreement.
Our internal team isn’t unified in its opinion either; some say it should be done for each batch according to the technical agreement. It is also said that it’s fine to produce one piece per furnace according to GB713; producing one piece per batch is certainly good, but is it necessary to retest the materials? The cost is also exorbitant. If only one piece is produced per furnace, there is a concern that it may not meet the technical specifications. I would like to ask whether the requirement to \"test mechanical properties and cold bending properties as approved\" includes high-temperature tensile testing as well Should high-temperature stretching be done separately?
It should be done in batches, with the chemical composition determined per furnace. In my opinion, high-temperature tensile testing should also be included; this was probably specifically mentioned by the designers in the technical requirements. Re-inspection is definitely necessary, and it should be carried out on a batch basis
In my opinion, it is necessary to discuss this with the design team to determine whether it was a lapse in their consideration or an additional requirement stemming from the design intent; after all, container manufacturing must comply with the specifications outlined in the design documents, and meeting relevant regulations and standards is the minimum requirement.