There are standard requirements for the wall thickness of hot-rolled seamless pipes; what are the requirements for the wall thickness after they are processed into elbows?

The standard requirements for the wall thickness of hot-rolled seamless pipes can be specified in accordance with various industry standards or international standards. After being processed into elbows, the wall thickness requirements must comply with the relevant standard specifications. Generally, the wall thickness of the elbow after processing should meet the standards specified in ASTM A234 to ensure the quality and performance of the resulting elbow. The requirement for thickness reduction in cases of external bending generally needs to be evaluated based on the specific operating environment and the functions to be achieved. In situations where high pressure or high temperatures are present, the wall thickness of elbows needs to be greater in order to ensure they can withstand such high pressures and temperature changes. At the same time, during the processing of elbows, special treatment is required for the outer curved portion to ensure uniformity in wall thickness and stability in thickness. .

GB/T12459-2017: Read it a few more times and you’ll find the answer

Thank you very much. However, elbow fittings are usually manufactured in accordance with the standard SH/T 3408—2022, which does not specify the thicknesses of the inner and outer curves. Therefore, it is difficult to require suppliers to follow the standards set out in GB/T12459-2017.

Before replying with convincing arguments, please read SH/T3408-2022 carefully. . . It’s not difficult; it’s just a few dozen pages, most of which are size tables.

It’s not difficult to find the relevant requirements. .

I don’t understand; which one is the tolerance for the inner and outer arc thicknesses?

So you’ve been struggling with this. . . The standard specifies the wall thickness at the edges, but you are looking for the tolerances for the inner and outer arc thicknesses. . .

No other requirements; the wall thickness must meet the nominal wall thickness at minimum. This is what general design requirements dictate.

First, the wall thickness of the elbow is calculated based on the process parameters; once the strength requirements are met, it must be compatible with the wall thickness of the connected pipes, in order to satisfy the welding requirements. If the wall thicknesses of the two are very different, high-strength materials need to be considered.