In the production and selection process of galvanized pipes, size parameters, weight coefficients, and execution standards are key factors that affect product quality and application effectiveness. Understanding these technical indicators can help engineering procurement and design personnel make more reasonable material selection decisions.
Nominal wall thickness and weight coefficient
The common specifications for the nominal wall thickness of galvanized pipes include: 2.0mm, 2.5mm, 2.8mm, 3.2mm, 3.5mm, 3.8mm, 4.0mm, and 4.5mm. The corresponding weight coefficient parameters (c) are 1.064, 1.051, 1.045, 1.040, 1.036, 1.034, 1.032, and 1.028, respectively. This coefficient is used to calculate the actual unit length weight of galvanized steel pipes and is an important reference for cost accounting and structural design.
Mechanical properties and commonly used grades of steel
The mechanical properties of steel are the core indicators to ensure the performance of galvanized pipes, mainly depending on the chemical composition and heat treatment process of the steel. In steel pipe standards, tensile properties (including tensile strength, yield strength or yield point, elongation) as well as hardness, toughness and other indicators are specified according to different usage requirements. Some users also require high and low temperature performance.
Common steel grades include Q215A, Q215B, Q235A, Q235B. These grades represent different strength levels and applicable ranges, and are widely used in low-pressure fluid transportation and structural pipe fields.
Test pressure requirements
According to current standards, galvanized pipes need to undergo a hydrostatic test before leaving the factory. The specific pressure requirements are: for steel pipes with an outer diameter range of D10.2mm to 168.3mm, the test pressure is 3Mpa; Steel pipes with an outer diameter range of D177.8mm to 323.9mm are tested at a pressure of 5Mpa. This testing process ensures that the product has sufficient pressure resistance and safety during use.
Current national standards
At present, the main national standards for the production and inspection of galvanized pipes include:
GB/T3091-2015 Welded Steel Pipes for Low Pressure Fluid Transport
GB/T13793-2008 "Straight seam welded steel pipes"
GB/T21835-2008 "Dimensions and Weight per Unit Length of Welded Steel Pipes"
The above standards provide clear regulations on the size specifications, allowable deviations, technical conditions, and weight calculation methods of galvanized pipes, which are the technical basis for both production enterprises and purchasers to comply with.
Industry insiders suggest that when selecting galvanized pipes, special attention should be paid to wall thickness parameters, brand grades, and whether they meet the latest national standards to ensure project quality and safe use.