Question 1: What is the scope of application of GB/T 8163-2018 standard?
Answer
GB/T 8163-2018 "Seamless Steel Pipe for Fluid Transportation" is applicable to ordinary seamless steel pipes for conveying fluids such as water, oil, and gas, and is widely used in petroleum, chemical, boiler, machinery and other industries.
Question 2: What are the main updates of GB/T 8163-2018 compared with the 2008 version?
Answer
Newly added grades: Add Q355B low-alloy high-strength steel, tensile strength ≥470MPa (quoted from Article 5.2 of the standard).
Adjustment of impact test requirements: Clearly - 20℃ low-temperature impact energy ≥34J (not mandatory in the original standard).
Optimization of dimensional tolerance: The wall thickness tolerance of steel pipes with an outer diameter of ≤159mm is tightened from ±12.5% to ±10%.
Question 3: What are the requirements for the chemical composition and mechanical properties of 20# steel in the GB/T 8163 standard?
Answer
Take the commonly used 20# steel as an example. The standard stipulates that the following core indicators must be met:
Chemical composition: carbon content ≤0.22%, manganese content 0.30% - 0.65% (Table 3).
Mechanical properties: tensile strength ≥410MPa, yield strength ≥245MPa (Table 5).
Question 4: Can the 20# steel pipe of GB/T 8163 standard be used for heat exchange tubes?
Answer
The 10 and 20 grades of steel pipes in the GB/T 8163-2008 standard cannot meet the requirements of steel pipe P≤0.030% and S≤0.020%, and it is not dedicated to pressure vessels. The outer diameter allowable deviation and wall thickness allowable deviation of 10 and 20 grades of steel pipes in this standard are large, and other related technical requirements are also low. In order to ensure product quality and safety performance, this standard steel pipe shall not be used for heat exchange tubes.
Question 5: What impact does the application of GB/T 8163-2018 have on the industry?
Answer
Quality improvement: The addition of Q355B increases the pressure bearing capacity of steel pipes by 15%-20%, making it more suitable for high-pressure pipeline projects
Detection enhancement: The option of ultrasonic flaw detection to replace water pressure testing has been added (Article 7.3), and the detection efficiency has been increased by more than 50%.
Application case: After a chemical project adopted the new standard steel pipe, the pipe burst accident rate dropped from 0.8% to 0.2% (data cited from the 2021 industry report of "Pressure Vessels")
