Differences between GB/T 12228 A105 and NB/T 47008 20
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As the title suggests, it’s the same project – both use CL150, but the media are different; in both cases it’s carbon steel. One flange is made from GB/T12228 A105 forgings, while the other is made from NB/T47008 20 steel – are there any significant differences in their properties? I don’t see any need for it; it’s completely fine to use the same one
Although both GB/T12228 A105 forgings and NB/T47008 20# steel belong to carbon steel materials, their main differences lie in the standards and application areas. A105 forgings are manufactured in accordance with American ASTM standards, and are widely used for piping and equipment connections under high pressure as well as high and medium temperature conditions ； On the other hand, 20# steel is manufactured in accordance with Chinese national standards and is typically used in low-pressure and medium-to-low temperature environments. In terms of performance, the A105 material offers relatively good temperature and pressure resistance, making it suitable for more demanding working environments. 20# steel has advantages in terms of cost and workability, making it suitable for general industrial applications. Theoretically, the two materials can be used interchangeably if the medium, pressure, and temperature conditions of the project permit it, but factors such as the availability of raw materials, costs, and relevant design standards must also be taken into consideration. It is recommended to consult relevant designers or technical experts to ensure that the most suitable materials are chosen to meet the project’s requirements. .
The temperature and pressure ratings are different; at temperatures below 200°C, A105 can withstand higher pressures at the same temperature.
The pipe materials used in conjunction with A105 flanges are usually also American standard materials, while the pipe materials used with 20# steel flanges are typically 20# steel pipes.
In reality, they’re all at room temperature and both have a pressure of 150 pounds; one is used for water and the other for flammable process media. But I think for the same type of project, where the working conditions of the media are similar, it’s sufficient to use just two sets of specifications. Doing so would be complicated from a procurement or design perspective, and I feel it leads to confusion – there’s no need to make distinctions just for such minor differences
The problem is that the operating temperature is room temperature; therefore, I don’t see why two different flange manufacturing standards would be chosen – one based on national standards and the other on ASME standards. If there is any difference, it’s that one standard is applicable for non-flammable media, while the other is for flammable media
The pipes all use 20 GB/T8163, which is why I’m puzzled
If 20# steel is used for the flanges on oil products, and its temperature and pressure ratings are sufficient, it can be used. The original design isn’t necessarily flawed either; some design institutes that are accustomed to using carbon steel opt for A105
Yes, both socket welding and butt welding use A105 forged steel