Is flaw detection required?
Thread Content
The pipeline for liquid nitrogen after the evaporator is DN40, made of stainless steel, and welded using TIG welding. Does this pipeline need to be inspected for defects?
It is best to have the weld inspected, so it can be used with confidence.
Liquid nitrogen is a hazardous substance, and this pipeline requires flaw detection
Flaw detection: 100%. Although the temperature range suitable for stainless steel is met, stress exists at the weld areas
Liquid nitrogen is a hazardous substance, and this pipeline requires flaw detection
For flaw detection, 100% RT!
1. Check the pressure behind the evaporator; if all the liquid nitrogen has vaporized into gas and the pressure is less than 1.6 Mpa, then the pipes behind the evaporator are not considered special equipment. It is sufficient to conduct flaw detection in accordance with the requirements specified in the construction drawings or by the design team, as there are no mandatory regulations requiring such action； 2. After evaporation in the evaporator, if the pressure is 1.6 Mpa or higher, it should be classified as a pressure pipeline, and the inspection ratio shall be in accordance with GB/T20801-2006.