Issues related to re-inspection of austenitic stainless steel flat plates
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Clause 5.1.1 of GB/T 150.4-2011 stipulates that re-inspection is required for the following materials: d) austenitic stainless steel flat plates used in the manufacture of components subject to primary compressive stresses. The explanation in the definition of 150 also clarifies why re-inspection is necessary. Question: Do composite plates with an austenitic stainless steel coating need to undergo material re-inspection in accordance with this requirement? For example: For the composite plate S30403+Q345R (3+20)*2000*6000, is it necessary to retest the 3mm thick S30403 sheet? The laminate of the composite panel serves only as a corrosion-resistant layer; its strength is not taken into account in the calculations regarding its load-bearing capacity during design. I would appreciate guidance from those with more experience. Requirements for 150 are provided along with their explanations
They are generally treated as compressed elements, and flat plates should be avoided as much as possible
Strength calculations are not performed because the composite layer serves mainly as a protective coating; there is also the issue of shear resistance between the composite layer and the base material. The standards allow the composite layer to be taken into account in strength calculations, using an equivalent allowable stress, but certain requirements related to the composite layer must be met
If it’s necessary to say that tablets cannot be used, it doesn’t seem like the standards explicitly state such a restriction; perhaps I just haven’t paid much attention to those standards
It doesn’t say that flat sheets cannot be used; it’s a question of whether retesting is required when using flat sheets. Most of the thin sheets available on the market are flat sheets
Re-inspection is also something that manufacturers of composite panels need to carry out; you just need to ensure that the performance of the composite panels meets the standards specified in NB/T47002.
We simply require the composite panel manufacturers to provide a re-inspection report from Kaiping
In GB/T26929-2011: A compressed element is defined as a component of a container that is subjected to compressive loads (including internal or external pressures). When composite steel plates are used to construct container shells, although the stainless steel layer serves as the corrosion-resistant layer, it is still a pressure-bearing element. According to the definition of primary pressure-bearing elements in TSG 21-2016, the shell and the head are considered primary pressure-bearing elements; moreover, the regulations on fixed storage tanks do not provide any exception for the corrosion-resistant layer of composite plates. Therefore, literally speaking… It is the main stressed component. So your open flat panel still needs to be retested here. I also checked the explanations in GB/T150.4; opening the flat sheet leads to a decrease in the elongation rate of austenitic stainless steel coils after fracture, which means that the toughness of austenitic stainless steel decreases. Used as a corrosion-resistant layer, it should have good pressure conductivity; it cannot bear pressure on its own, so it needs to be tough. Therefore, from this perspective. Flat-panel screens also need to be retested.
This post was last edited by zjq1962 on 2020-8-22 at 13:06. The key question is: are there still composite steel plates as well as flat sheets? As for whether the sheets should be flat-rolled before compounding, I personally think it’s not necessary to consider it. The manufacturing process of composite steel plates requires stress-relief heat treatment; even if flat steel plates are used, cold working hardening is eliminated.
I agree with you, that’s why I’m posting this to discuss the issue.