For fittings with a diameter of less than 250 mm, is flaw detection required for the longitudinal seams?
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For fittings with a diameter of less than 250 mm, which are welded by rolling, is it necessary to inspect the weld joints? What is the basis for this?
For fittings with a diameter of less than 250 mm, if non-destructive testing is required, it is usually carried out on the welds. The flaw detection of longitudinal seams should be determined based on actual conditions and design requirements. For self-welded joints, non-destructive testing is generally also required to ensure the quality and safety of the welds. It is based primarily on manufacturing standards, design specifications, and project technical requirements. For specific details, refer to China’s standards **“Steel Pressure Vessels” (GB 150)** and **“Rules for Manufacturing and Inspection of Pressure Vessels” (TSG R0004)**, as well as other relevant international and industry standards. These standards and specifications detail the requirements for the manufacturing, inspection, and acceptance of pressure vessels and fittings. In practice, it is also necessary to comply with the project’s technical requirements and customer needs; if there are any special requirements, they must be agreed upon in advance with the relevant parties. In short, safety and quality should always come first. .
There’s another AI upstairs. The designers will make a judgment based on the hazard level of the equipment. It’s also too small; generally, forged pipes or standard seamless pipes are used, and even welded pipes come in standard sizes. I haven’t encountered a situation where I had to coil a small tube under pressure yet. Even if the designer does it this way, the reviewer will still ask for the design to be changed, right?
It seems that flaw detection inspections are related to the stress-bearing factors; for reference only.
Bizarre design or manufacturing – to produce something with such a small diameter, one really needs talent； Longitudinal seams designed and inspected in accordance with GB/T150 require non-destructive testing.
Generally, it’s difficult to roll sheets below 350; is it hard to purchase seamless tubes below 250?
If you’re still using welded pipes for values below 250, you’re just creating unnecessary problems. No manufacturing plant does this either. In certain situations, welded steel pipes can be used for stainless steel pipes; in other cases, radiographic or ultrasonic testing is required.
As long as it is designed properly, seamless pipes will be chosen for sizes below DN250, right?
If you roll it yourself, flaw detection is definitely necessary
It was just that little piece of tube, and it was made of a non-ferrous metal, so I rolled it myself.