Materials for ear-type supports
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The NB/T47065.3 standard specifies the allowable stresses only for the materials Q235B, S30408, and 15CrMoR; the commonly used materials Q235R and Q345R do not have specified allowable stresses； Now a problem arises: for a vertical vessel whose main material is Q345R, if Class I material is used, the strength verification fails, while it passes when Class III material is used. Does that mean that even when the main material is Q345R, supports made of 15CrMoR material are still required? In the past, Q345R was generally used for this purpose, but there was no basis for doing so.
This post was last edited by Shutong on 2020-11-1 at 17:29. For NBT 47065.1-5-2018, Q235B, Q345B, and Q345R are the materials commonly used for container supports; Q345R is preferred for the main components, and it is also generally used for the supports. Scrap materials can be used as well :) The choice is based primarily on strength requirements. It is not necessary to use Q345R, but the gussets should still be made of Q345R
The new standard has removed 16MnR, but the old standard JB 4712.3 can be referred to
It’s the third part, but there is no corresponding applied stress.
The supports cannot be properly labeled; in JBT 4712.3, Class II material is 16MnR, while in NB/T47653.3, Class II material is S30408. The current marking practice is NB/T47065.3-2018: Ear-type support, C2-Ⅰ, material Q345R ； It just seems not rigorous enough.
It’s a fully designed set, with all stresses taken into account
Generally, supports are not taken into account; they are calculated only in some specific cases. Without the corresponding allowable stress values, it is impossible to conduct strength checks, and without such checks, there is no sufficient basis to determine whether the selected model is appropriate or not.
This standard is clear enough; there’s no need to overcomplicate things
Except for the shims, the allowable stress of the materials is in accordance with the structural design codes.
This post was last edited by zjq1962 on 2020-11-4 08:40. The instructions for drafting the bearing standards address this issue.