High temperature tensile test retest issues

Re-inspection requires sampling by the manufacturer and a re-inspection report. The inspection results of the steel mill cannot replace the re-inspection of the manufacturer.

Testing by the steel mill cannot replace re-inspection by the manufacturer.

Fixed capacity regulations: The pressure vessel manufacturing unit shall be responsible for the authenticity and consistency of the pressure vessel materials and material quality certificates. So if you don't re-inspect, how can you ensure quality?

“How to ensure quality without re-inspection? ” I don’t quite agree with this. “"Responsible for the authenticity and consistency of pressure vessel materials and material quality certificates" does not mean that re-inspection is necessary. The following situations require re-examination:: 1 Large capacity gauges require re-inspection, such as Class IV forgings ； 2 Design documents require re-examination, such as the case of the original poster ； 3. The manufacturer's quality assurance department requires re-inspection, such as materials that have been in stock for many years. In addition, re-inspection is a verification inspection, and not all items need to be re-inspected. When there are no specified items, only the chemical composition and mechanical properties need to be retested.

Agree with your narrative. What I am saying is in response to the situation mentioned by the poster, not that all materials need to be re-inspected. I believe that re-inspection should be carried out for non-mandatory contents such as "demand party requirements" and "agreement" in material standards, as well as special technical requirements in design documents. To ensure the quality of materials.

The picture only indicates the need for high-temperature tensile testing. If the material manufacturer has already issued a certificate of high-temperature tensile testing, and there is no problem with the reliability of the certificate, why do we need to retest it? And this re-inspection of the manufacturing plant is more troublesome, right? If you ask me to say that this technical requirement is a bit unreasonable, if it were me, I would change the word "retest" in the requirement to "test". Nowadays, standards have greatly reduced the re-inspection requirements for materials. In the past, the market was chaotic and the reliability of many certificates was not very high. For important equipment, many things need to be re-inspected after entering the factory. At this stage, as long as it is a certificate from a regular manufacturer, and the manufacturer itself is also responsible for material procurement, re-inspections can be reduced a lot. Of course, as far as the poster is concerned, the drawings have already made re-inspection requirements, so the steel mill’s experimental proof cannot replace the re-inspection and needs to be done again.