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Production Process Of Galvanized Pipe

Feb. 21, 2020

Galvanized pipe manufacturer introduces you:

Galvanized steel pipes are welded steel pipes with hot-dip galvanized or galvanized coating on the surface. Galvanizing can increase the corrosion resistance of the steel pipe and prolong its service life. Galvanized pipes have a wide range of uses. In addition to being used as pipeline pipes for water, gas, oil and other general low pressure fluids, they are also used as oil well pipes, oil pipelines in the oil industry, especially offshore oil fields, oil heaters for chemical coking equipment, and condensation Pipes for coolers, coal-distilled wash oil exchangers, as well as trestle pipe piles, pipes for support frames of mine tunnels, etc.

The production process of galvanized steel pipe belongs to the secrets of each manufacturer, so it can only provide the approximate process flow: a. Round steel preparation; b. Heating; c. Hot-rolled perforation; d. Cut head; e. Pickling; f. Dressing; g. Lubrication; h. Cold rolling; i. Skim; j. Solution heat treatment; k. Straightening; l. Cut the tube; m. Pickling; n. Product testing.

Technical requirements and standards of galvanized pipe

1.Grade and chemical composition galvanized pipe

The grade and chemical composition of the steel used for galvanized steel pipes shall comply with the grade and chemical composition of the steel used for black pipes as specified in GB-3092.

2.Manufacturing method of galvanized pipe

The manufacturing method of the galvanized pipe (furnace welding or electric welding) is selected by the manufacturer. Most of the galvanizing uses hot-dip galvanizing.

Galvanized Steel Pipe

Galvanized Steel Pipe

3. Galvanized pipe thread and pipe joint

(1) For galvanized steel pipes delivered with threads, the threads should be turned after galvanizing, and the threads should meet the requirements of YB-822;

(2) Steel pipe joints shall comply with YB-238, and malleable cast iron pipe joints shall comply with YB-230.

4.Specifications of galvanized pipe

Nominal wall thickness (mm): 2.02.52.83.23.53.84.04.5 Weight coefficient c: 1.0641.0511.0451.0401.0361.0341.0321.028

5.Mechanical properties of galvanized steel pipe

The mechanical properties of steel pipes before galvanizing shall meet the requirements of GB-3092. The mechanical properties of steel are important indicators to ensure the end-use performance (mechanical properties) of the steel, and it depends on the chemical composition and heat treatment system of the steel. In the steel pipe standard, according to different usage requirements, tensile properties (tensile strength, yield strength or yield point, elongation), hardness and toughness indicators, as well as high and low temperature properties required by users are specified.

6.Uniformity of galvanized layer of galvanized pipe

Galvanized steel pipe shall be tested for homogeneity of the galvanized layer. Samples of galvanized steel pipes should not be red (copper-plated) after 5 consecutive immersion in copper sulfate solution.

7. Cold bending test of galvanized pipe

Galvanized steel pipes with a nominal diameter of not more than 50mm should be subjected to cold bending test. The bending angle is 90 °, and the bending radius is 8 times the outer diameter. The test shall be carried without fillers, and the welds of the test specimens shall be placed on the outer or upper part of the bending direction. After the test, there should be no cracks or zinc peeling on the sample.

8.Hydraulic test of galvanized pipe

The hydrostatic test of galvanized steel pipe shall be carried out on a black pipe, and the hydrostatic test may be replaced by eddy current testing. The test specimen or eddy current inspection comparison specimen size shall meet the requirements of GB-3092.