Is it necessary to use 20G material for heat transfer oil pipelines?
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For a heat transfer oil pipeline with a design pressure of 0.6 MPa and a design temperature of 350°C, I think GB/T8163 20# would be suitable. The client insists on using 20G, saying that boiler steel can withstand high temperatures; is 20G more heat-resistant than 20? Shouldn’t it be resistant to high pressure?
Pipe with code 3087 should be used
This is a fairly normal requirement; 20G is generally used for 350 degrees.
Steel grade 20 belongs to the category of high-quality carbon steels. The designation “20” indicates that the average carbon content in this steel is 0.20%. At a temperature of 315°C, the thermal conductivity of steel grade 20 is 48 watts per meter per degree Celsius. Steel grade 20 is generally not subjected to quenching; instead, carburizing or normalizing are the common treatment methods used for it. Steel grade 20G is a type of boiler steel that is similar to steel grade 20. The difference lies in the fact that 20G has stricter requirements regarding harmful impurities and internal defects, as well as more stringent inspection standards compared to steel grade 20. In other words, 20G is a special-purpose version of “steel grade 20”, designed specifically for use in boilers and pressure vessels.
I think the 9948 tube will be sufficient; there’s no need for the 20G version of 5310