The two grades of DN150 pipes in HG20553, sch.30 and sch.60, have no wall thickness. How to determine it?
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In the HG-T 20553-1993 Seamless and welded steel pipe size selection series for chemical piping, the two table numbers sch30 and sch60 of DN150 pipes do not have wall thickness, but in reality there are these two table numbers. How to determine the wall thickness of these two table numbers? Or what standards can we refer to?
The pipe table number only plays the role of grading the pipe wall thickness and has no other meaning. The back wall thickness can be deduced based on the calculation formula used to determine the pipe number.: t=(Tube table number xD/(1.75X1000)+0.1 where: D is the outer diameter, t is the wall thickness
I did the calculation using the method introduced on the second floor.: For example, the pipe thickness of DN150 and SCH30 is 20 * 159/1750+0.1=1.92 It is simply impossible to use such a thin pipe wall thickness. The hg20553ii series is an old standard still used in China, mainly considering the reconstruction or expansion of old factories. Does anyone have the table number of this series of steel pipes - wall thickness series? The HG20553 standard has its own II series wall thickness table, but does not indicate the table number. How to judge? This post was last edited by yangnian2001 on 2008-2-18 18:32 ]
Go back upstairs: Sorry, D in the formula refers to the outer diameter of the pipe, and the unit is inches. Calculated as follows: t=30x6.625/1750+0.1=0.214 inches (equivalent to 5.44 mm). This formula is the theoretical thickness formula for calculating the wall thickness of pipe numbers given by American ANSI B36.10, which can be used to establish a reasonable wall thickness series. Since the Sch classification of pipe wall thickness was originally adopted by the United States and Japan, the II series in the HG20553 standard is an old standard still used in China. There should be no such thing as the wall thickness series of steel pipe numbers for this series. If the II series of HG20553 standard is used, the selection of pipe wall thickness will ultimately be determined by the pipe wall thickness strength calculation formula.: t=PD/（200［σ］+P） +C where: t——pipe wall thickness, unit: mm P - working pressure inside the pipe (kg/cm2) D - outer diameter of the pipe, in millimeters. φ——Weld coefficient, φ=1 for seamless steel pipe, φ=0.8 for straight seam welded steel pipe, and φ=0.6 for spiral seam welded steel pipe. [σ]——The allowable stress of the pipe (kg/mm2). Check the allowable stress at the actual operating temperature. C——The additional amount of pipe wall thickness, unit: mm
You can't just consider it from the perspective of design thickness, you also need to consider whether it can be purchased. If the thickness you calculated is between SCH10 and SCH40, you still need to use SCH10 or SCH40 as a substitute when it comes to actual manufacturing and procurement. If you don't use the substitute, you may need to purchase a large amount. Many factories require a single specification of more than 500KG before production. Therefore, it is recommended that designers not only consider the safety of the design, but also consider the actual situation and economy.
Are there any discrepancies in the formula on the fourth floor? Page 200 of the pressure pipeline design approval and assessment textbook is: t=PD/（2［σ］t * Φ+2PY)+C
Reply 4# Li Yiheng please ask: How is the outer diameter 6.625 inches obtained?