Allowable stress of steel pipes and allowable stress of steel materials
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When using software for pipeline stress analysis, it is necessary to enter the allowable stress of the steel pipe. Is the allowable stress of the steel pipe the same as the allowable stress of the corresponding material? While reviewing several standards recently, I found that for steel plate welded pipes made of Q235-B material, the allowable stress specified in Appendix A of GB50316-2005 (2008 edition), the \"Code for Design of Industrial Metal Piping\", is 113 MPa (at ≤150°C). In GB/T20801.2-2006, the \"Code for Pressure Piping – Industrial Piping\" (Part 2: Materials), the allowable stress for Q235-B plate welded pipes in section 2.2.2 is 125 MPa (at ≤100°C). Additionally, the allowable stress for Q235-B material as given in Table 3 of P10 in SH/T3073-2004, the \"Code for Design of Supports and Hangers for Petrochemical Piping\", is 83 MPa (at ≤200°C). Does the allowable stress increase after the steel plate coil is welded into a pipe? But why are there differences in the allowable stresses specified in the first two standards? This is of great significance for selecting the allowable stress when we perform stress analysis calculations. I wonder what allowable stress values people use when performing stress calculation analyses on metal pipes? (Material: Q235-B)
Note that the allowable stress temperature ranges specified in these several standards are different. But I remember that the allowable stresses under American standards and domestic standards are different. Furthermore, the allowable stress for welded steel pipes should be lower than that for seamless steel pipes.
The safety factors adopted under different standards may vary, and the manufacturing acceptance criteria (related to material quality) are also different.
First of all, it is necessary to distinguish between true stress and the stress as defined in our standards. True stress is the reaction force exerted by an elastic material under external forces, whereas the stress we consider is merely a relative value. Therefore, we cannot state what the allowable stress for a particular material is; different standards use different values for allowable stress. As mentioned on the second floor, the scaling factors used vary, and this can be seen from the formulas for allowable stress in GB150 and ASME.
I don’t have the right to speak on this yet; I need to learn more