Is there a difference between boiler steel pipes 20G and 20g?
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Is the material different, and what about its pressure resistance?
20G and 20g are the same
Fellow upstairs, if you don’t understand something, don’t pretend to do; it’s to avoid misleading others.
20g is the grade for boiler steel plates (GB 713-1997), while 20G is the grade for high-pressure carbon steel boiler tubes (GB 5310-1995); they are fundamentally two different materials with distinct manufacturing processes, compositions, and properties. What is the difference between 20G and 20g? 20g – pronounced as 20 Guo – refers to steel plates, and its allowable stress is not specified in GB150-1998; it can be used as a substitute for Q235-C； 20G – read as 20 High; it is a type of pipe that complies with the specifications in GB6479-2000 \"Seamless Steel Tubes for High-Pressure Fertilizer Equipment\", and its allowable stress is specified in GB150-1998. One of them is in sheet form and the other in tube form; logically, they cannot be compared. However, to illustrate the point, let’s take a look at their main characteristics: 1. Phosphorus and sulfur content – For 20g grade: P content ≤ 0.035%, S content ≤ 0.035%; for 20G grade: P content ≤ 0.030%, S content ≤ 0.030%. Of course, there are also differences in the content of other chemical elements. 2. Tensile test: 20g: σb (MPa) 400–520, σs (MPa) ≥225, δ5 (%) ≥24; 20G: σb (MPa) 410–550, σs (MPa) ≥245, δ5 (%) ≥24. 3. Impact test: 20g: temperature 20°C, transverse Akv ≥27 J; 20G: temperature -20°C, longitudinal Akv ≥18 J or Auv ≥39 J
20G and 20g are the most commonly used steels for boilers. 20G is widely used in boilers’ economizers, superheaters, convective tubes, water walls, and various manifolds; therefore, it is easy to assume that 20G is the same as 20g. In fact, 20G and 20g are two different materials used in various components of boilers. 20G possesses good bending and welding properties, which is why it is widely used in the manufacture of heat-exchange tubes in boilers where the wall temperature is below 480°C; for this reason, some consider 20G to be a type of tube steel. Plate rolled from 20G steel is steel plate specifically designed for boilers; the steel plate used to manufacture steam drums is usually 20G steel. Boiler steel plates of the same grade and hot-rolled steel plates for general purposes differ little in chemical composition and normal mechanical properties, but boiler steel plates can ensure specified impact values and aging impact values, whereas steel plates for general purposes cannot. This post was last edited by yps_78 on 2009-3-27 10:39.]
20g refers to sheet material, while 20G refers to tube material. The explanation on the 5th floor was very detailed! I’ve learned it too!
20G special boiler steel; 20G is what is known as steel grade 20
20G boiler plate, used for making boiler drums. 20G refers to grade 20 steel; it is used for manufacturing pipes – high-pressure resistant pipes, I guess~~
20g — read as 20 Pot; sheet material for boilers. 20G — read as 20 High; high-pressure pipes