Seeking advice on quality assurance certificates for raw materials of pressure vessels
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Our factory has recently received a batch of raw materials made of Q235B with a thickness of 6 MM. I noticed that the material quality certificate does not contain data regarding impact strength. I’m not sure if there’s a problem; it seems there’s a rule stating that components under 6 MM don’t need to undergo impact testing, but I’m not certain whether 6 MM is included in this category ? ? ?
To be honest, there are all kinds of warranty certificates these days, with all sorts of data on them that’s impossible to understand; some of those figures are completely absurd. The suppliers don’t really care about this, and it’s unclear whether they even understand what those numbers mean – sometimes they themselves don’t know what they signify. If a company conducts thorough inspections upon receipt of goods and finds issues with the data, it can immediately request a replacement warranty certificate. I really don’t understand how such warranty certificates come about. In short, the data on warranty certificates isn’t necessarily reliable, and companies just use them as evidence to shift responsibility for their own protection. If actual re-inspections are carried out, how many of the data values on those warranty certificates will turn out to be valid? The thickness of the steel plate you mentioned requires an impact test. The dimensions of the impact specimen are: 5*10*55 or 6*10*55. You can refer to the technical requirements in GB700-2006 for carbon structural steel”
Material Q325-B is not subjected to impact testing.
I’ve just started in this field, and there are many things I still need to learn by asking around. I also hope you can advise me on which standard is used as the basis for not using Q235-B in applications that involve impact forces – the two colleagues on the 3rd and 4th floors.
It depends on the design temperature specified in your order requirements to determine whether it’s necessary
Q235-A does not require impact testing, while Q235-B needs to undergo impact testing at room temperature (20°C); for details, refer to Articles 5 and 6.1.3 of standard GB700-88. Steel plates with a thickness of 6 mm can be subjected to impact testing using a small-size specimen.
Material acceptance shall be carried out in accordance with the requirements of the material standards (and any other specified requirements as well). Therefore, the impact test values should be included in the quality certificate for Q235B. When Q235B material is used in container manufacturing, is impact testing required? Clause 10.5.6.5 of GB150 stipulates that \"the dimensions of the test plates and the method for taking samples shall be in accordance with the provisions of Appendix E (the standard appendix).\" If the shell material (except Q 235B and C) has impact requirements, impact specimens should also be taken from the test plate for impact testing. ”
It is not necessary to apply impact energy; you can refer to GB/T700, which covers this topic
Raw materials do not require impact test, but pressure vessel materials need to have their suitability for impact testing determined based on the operating temperature.
GB700-2006 specifies that for Q235-grade B steel with a thickness of less than 25 mm, if the supplier can ensure that the absorption energy value is within the specified limits, then, with the buyer’s consent, testing may be omitted. Nevertheless, it seems that the supplier still needs to provide the absorption energy value without your consent