Selection of pipe material for GC1 grade

You can take a look at GB/T20801-2020.

This post was last edited by wfzhang on 2023-12-2 at 21:51. I took another look at the specifications; there is a note 7 stating that use at pressures above 4 MPa in category A1.1(1) is not allowed. In other words, it cannot be used with extremely toxic or highly toxic media, nor with flammable liquids whose boiling point is above a certain level, under conditions where the pressure exceeds 4 MPa. So, what type of pipe should be used for GC1-grade pipes with a pressure greater than 4 MPa?

In TSG D001-2009 \"Regulations on Safety Inspection of Industrial Pipelines\", pipelines are indeed classified into GC1, GC2, and GC3 grades according to different safety levels. For GC1-class pipelines, these generally refer to steam pipelines with a working pressure of 10.0 MPa or higher and a working temperature of 350°C or higher ； Or pipes containing highly toxic media or explosive media ； Or other pipelines that require an equivalent level of security management. Due to the extreme operating conditions, these pipelines require very high standards in terms of material and safety performance. GBT8163-2008 is the standard number for China’s standard titled \"Seamless Steel Tubes for Liquid Conveyance\"; this standard specifies the dimensions, appearance, and technical requirements of seamless steel tubes used for conveying ordinary fluids. Due to the special operating conditions of GC1-grade pipes, higher standards may be required for both the materials used and the manufacturing processes; for instance, better resistance to high temperatures, high pressures, and corrosion is needed. As a result, ordinary seamless steel pipes in accordance with the GBT8163-2008 standard may not meet the requirements of GC1-grade pipes. When selecting the material for GC1-grade pipelines, the following types of steel pipes are generally considered: 1. High-temperature and high-pressure seamless steel pipes: Such as those produced in accordance with the GB5310-2008 standard for \"Seamless Steel Pipes for High-Pressure Boilers\", and these pipes are suitable for use in manufacturing boilers and pipelines that operate under high temperature and pressure conditions. 2. Alloy steel seamless pipes: The addition of alloying elements can improve the heat resistance, pressure resistance, and corrosion resistance of these pipes. 3. Stainless steel pipes: For transporting media with certain corrosive properties, stainless steel pipes may be chosen to ensure that the media do not cause corrosion to the pipe material. 4. Pipes made of special materials: For certain specific applications, such as those involving extreme temperatures or highly corrosive environments, custom materials and technologies may be required. When selecting the material for pipes, it is necessary to take into account factors such as the properties of the medium, operating temperature, operating pressure, and environmental conditions, and it must also comply with relevant standards and specifications set by ** and the industry. Typically, close collaboration is also carried out with qualified pipeline design departments and professionals during the design and selection process to ensure the safety and reliability of the pipelines. .