Who has the standards or software tools for pressure and pipe wall thickness?

This was just delivered; it should be enough for your needs

The wall thickness of a pipe is related not only to the design pressure but also to the allowable stress at the corresponding design temperature. Therefore, the wall thickness is calculated; it does not have a one-to-one relationship with the design pressure.

Agree with the 3rd floor! The calculation formulas for different types of pipes vary slightly; for details, refer to Gc: GB50316, GB20801; GA: GB50251 and GB50235; GB: GB50028.

This post was last edited by keveyo on 2011-1-4 at 16:05. attach://733984.rar My colleague also created a spreadsheet for calculating wall thickness using EXCEL, in accordance with the design specifications for industrial metal pipes; those who need it can download it from attach://733981.rar

Just use SW6 for the calculations (enter the values directly); those tables contain empirical values, and they don’t necessarily ensure that the materials are utilized to the fullest extent!

It can be determined through calculation or by referring to relevant manuals; here is one method to try. 1. Calculation formula: In the formula, δ represents the wall thickness of the tube, in mm； P — Operating pressure of the medium in the pipe, Mpa ； D—outer diameter of the pipe, mm ； F—is the weld coefficient; for seamless steel pipes, F=1; for straight-seam welded steel pipes, F=0.8; for spiral-seam welded steel pipes, F=0.6 ； t—allowable stress of the pipe at operating temperature, Mpa ； The allowable stresses for commonly used steel pipes and steel plates are given in Table 1: C—additional value for pipe wall thickness, mm ； C=C1+C2+C3; C1 is the negative tolerance for the wall thickness of steel pipes or steel plates, in mm ； The negative tolerance for the wall thickness of welded steel pipes made from steel plates is equal to the negative tolerance of those steel plates. The negative tolerances for various seamless steel pipes and steel plates are shown in Table 2 below: C2—corrosion allowance, mm ； Its value depends on the corrosivity of the medium and the service life of the steel pipe; for carbon steel and low-alloy steel, C2 should be no less than 1 mm, while for stainless steel, C2 is set to 0 when the corrosivity of the medium is extremely low ； C3—thread depth, mm ； Its value can be found in Table 3; if there are no threads on the pipe, then C3=0 ； Table 1: Rated Allowable Stresses for Common Steel Tubes and Sheets
Steel Grade | Thickness / mm | Rated Allowable Stress / MPa at the Following Temperatures (°C): ≤20, 100, 150, 200, 250, 300, 350, 400, 425, 450, 475
Common Steel Tubes:
10 | ≤10 | 113, 113, 112, 106, 106, 94, 88, 81, 78, 62, 41
>10–20 | 107, 107, 103, 91, 84, 78, 72, 67, 62, 62, 41
20 | ≤10 | 133, 133, 133, 131, 122, 112, 103, 97, 87, 62, 41
>10–20 | 127, 127, 125, 119, 112, 106, 97, 91, 87, 62, 41
16Mn:
≤10 | 167, 167, 167, 167, 156, 144, 136, 127, 95, 67, 43
>10–20 | 160, 160, 160, 159, 150, 138, 128, 122, 95, 67, 43
Common Steel Sheets:
Q235AF:
≤20 | 127, 127, 127, 125, 116
>21–26 | 127, 127, 122, 116, 106
Q235A:
≤20 | 127, 127, 127, 126, 116, 106, 97, 91
>21–26 | 127, 127, 125, 119, 109, 100, 94, 88
20q:
6–16 | 137, 137, 137, 131, 122, 113, 103, 97, 87, 62, 41
17–25 | 137, 137, 131, 125, 119, 109, 100, 94, 87, 62, 41
16Mn:
≤16 | 173, 173, 173, 173, 166, 153, 144, 127, 95, 67, 43
17–25 | 167, 167, 167, 167, 156, 144, 134, 127, 95, 67, 43

Table 2: Negative Tolerances for Steel Tubes
Tube Type | Specification Dimensions / mm | Precision | Ordinary Grade /% | Advanced Grade /%
Carbon Steel and Alloy Steel:
Cold-drawn Tubes:
Thickness 1–3 | -10 | -10
Thickness >3 | -10 | -10
Hot-rolled Tubes:
Thickness 3–20 | -15 | -12.5
Thickness >20 | -12.5 | -10
Stainless Steel Acid-resistant Tubes:
Cold-drawn Tubes:
Thickness 1–3 | -15
Thickness >3 | -12.5
Hot-rolled Tubes:
Thickness ≤10 | -15
Thickness 11–20 | -20
Thickness >20 | -15
Negative Tolerances for Hot-rolled Steel Sheets of Ordinary Carbon Steel and High-quality Steel:
Sheet Specification | Precision
Sheet Specification | Precision | Thickness

Reply to 2# superkiller0305, moderator: Which standard is your reference table based on, or which book does it come from? Are all these things still experience points?

Reply to 9# 516387460: The regulations regarding wall thickness are specified in many standards, but they apply to normal situations only. It’s better to calculate the pressure that can be withstood on one’s own; those of us who do design work shouldn’t seek shortcuts

Reply to 10# superkiller0305: I am a technician at a low-temperature valve factory! The pipes to be used mostly feature cartridge valves, with the valve stem enclosed on the outside; the pressure of such valves at low temperatures is below 4 MPa. There’s not much pressure at all, so I just want to find something for reference! Hehe

This post was last edited by bosslxt on 2011-2-22 at 17:03. I have created a file using EXCEL for wall thickness calculations; I welcome everyone’s feedback. The table also provides a function to look up the allowable stress for various grades of steel pipes.