Galvanized Steel Pipe

What is galvanizing?

Galvanizing is to make molten metal and iron matrix reaction as an alloy layer, so that the substrate and coating two combined. Galvanizing is to pickle the steel pipe first, in order to remove the iron oxide on the surface of the steel pipe. After pickling , through ammonium chloride or zinc chloride solution or ammonium chloride and zinc chloride mixed aqueous solution tank for cleaning, and then into the hot dip plating tank. Galvanizing has the advantages of uniform coating, strong adhesion and long service life. Widely used in agricultural greenhouses, fire system, gas, water supply, drainage and other fields.

Hot dip galvanized pipegalvanized pipe
The molten metal is reacted with an iron matrix to produce an alloy layer, thereby combining the substrate and the plating layer. Hot-dip galvanizing is to pickle the steel pipe first, in order to remove the iron oxide on the surface of the steel pipe, after pickling, it is washed by ammonium chloride or zinc chloride aqueous solution or a mixed aqueous solution of ammonium chloride and zinc chloride, and then fed. Hot dip plating tank. Hot-dip galvanizing has the advantages of uniform plating, strong adhesion and long service life.
Cold galvanized pipe
Cold galvanizing is electrogalvanizing. The amount of galvanizing is very small, only 10-50g/m2, and its corrosion resistance is much worse than that of hot-dip gal tubing. Regular galvanized pipe manufacturers, in order to ensure quality, most do not use electro-galvanizing (cold plating). Only small companies with small equipment and old equipment use electro-galvanized steel, of course, their prices are relatively cheaper. In newly built houses, the use of cold-galvanized steel pipes as water supply pipes is prohibited.

Difference hot-dip galvanizing and cold galvanizing
Hot dip galvanizing process:
Workpiece degreasing → washing → pickling → washing → drying solvent dip fluxing preheated hot dip galvanized → cooling → finishing → rinsing → drying → passivation test
Cold-galvanized process:
Chemical degreasing → washing → hot water hot water electrolysis degreasing → washing → washing → strong corrosive galvanized iron alloy → washing → washing → light → → washing → drying passivation

GALVANIZED STEEL PIPE PRODUCTION PROCESS

Galvanized steel pipe provided by GNEE
Pipe Type: Galvanized steel pipe, Hot Dip Galvanized Round Steel Pipe, Pre Galvanized Steel Pipe
Outer DiameterOD (mm)：
Pre galvanized:21.3-406.4mm
Hot dipped galvanized:21.3mm-610mm
Wall Thickness (mm)：
Pre galvanized:0.6-22mm
Hot dipped galvanized: 0.8- 25mm
Length:0.3mtr ~ 18mtr, Ramdon Length, Fixed Length, SRL, DRL
Standard and Grade: GB/T 3091 Q195/Q215/Q235/Q345, BS 1387, EN 39, EN 1139 S235JR/S275JR, ASTM A53 GR. A/B/C, JIS G3444 STK 400/STK 500,ASTM A53, EN 10025, EN 10219
Pipe Type: Seamless & Welded Steel Pipe (Round/Square/Rectangular)
End: Square Cut/Threaded, Burr Removed

Types of galvanized steel pipe

APPLICATION

Application:
1.Building and structural material
2.Mechanical and general engineering purposes
3.Manufacturing of Bus Body, Railway Boogies
4.In Telephone department as Conduit Pipes

 

 

 

 

GNEE main product is A53 galvanized pipe
A53 Pipe Materials & Manufacture
Steel materials used to create seamless pipe and welded pipe must be produced via open hearth, electric furnace, basic oxygen, or any combination of these processes. All weld seams in electric-resistance welded A53 Grade B pipe must be heat treated after welding to a minimum of 1,000°F (540°C) to eliminate untempered martensite.
Galvanized A53 Pipe
If ordered galvanized, A53 seamless pipe must be coated inside and out via the hot-dip process. Zinc used for galvanized coatings must conform to Specification B6. The weight of this coating must not be less than 1.8 oz./ft2 (0.55 kg/ m2). Test specimens for coating weight testing will be cut in approximately 4” lengths.
Permissible Variation in Wall Thickness
The minimum wall thickness at any point in a length of A53 steel pipe must not be more than 12.5% less than the specified wall thickness.
Permissible Variations in Outside Diameter
For ASTM A53 steel pipe NPS 1-1/2 and smaller, outside diameter must not exceed 1/64” over and 1/32” under specified diameter. For A53 pipe NPS2 and larger, outside diameter must not exceed 1% over and 1 % under specified diameter.
Hydrostatic Testing of ASTM A53 Pipe
Separate hydrostatic inspection test pressures are specified for plain end, threaded, and coupled A53 steel pipe. Minimum hydrostatic test pressure for NPS 3 and under is 2,500 psi; minimum test pressure for sizes over NPS 3 is 2,800 psi. Pressure must be maintained for a minimum of 5 seconds, for all sizes.
Mechanical Testing of ASTM A53 Pipe
Electric-resistance welded ASTM A53 steel pipe of NPS 8 and larger must be transverse tested. Sending test (cold) is required for STD and XS-NPS 2 and under, and for XXS-NPS 1-1/4 and under. Flatten testing is required for NPS 2 and larger STD and XS A 53 pipe; flatten testing is not required for XXS pipe.

If you need it for your project, please contact us in time! sales@gneetube.com

GALVANIZED STEEL TUBE TESTING

How long is the service life of galvanized pipe?
The service life of galvanized pipes is affected by many factors, including the thickness and quality of the galvanized layer, usage environment, maintenance, etc. Under normal circumstances, the service life of galvanized pipes is generally about 15-20 years, but specific factors need to be considered for the specific time.

How to maintain and maintain galvanized steel pipes?
Regularly check whether the coating of galvanized steel pipes is intact and whether there is any corrosion, damage or leakage. Check the tightness of the piping system. If there is any leakage, find and deal with it in time.
Regularly clean the surface of galvanized steel pipes to remove dirt and rust using appropriate cleaning agents and tools. For damaged galvanized coatings that require repair work, special coating repair agents can be used.
In the pipeline system, galvanized steel pipes that have not been used for a long time should be flushed with water regularly to prevent accumulation of substances in the pipes from corroding the steel pipes. Corrosion inside pipes can be prevented by using reliable coating materials such as paints and polymers.
When storing galvanized steel pipes, they should be placed in a dry, ventilated, moisture-proof place away from direct sunlight.
Avoid pinching and do not store ends too close together or on top of each other. The placement position should be kept stable, and the galvanized steel pipes should be cleaned and derusted before storage.

Requirements of galvanized insulated steel pipe in construction:
1, Galvanized insulated steel pipe is used for gas and natural gas, long-distance transmission of high pressure pipeline.
2. Galvanizing in order to preserve corrosion, in the long-distance transportation, the pole protection testing station is generally set up at several tens of kilometers to 100 kilometers. The instrument in the station generates cathode electrons to fill the pipeline, and the galvanized surface is conducive to conductive rust. The pipe is charged uniformly.
3, In order to prevent the loss of cathode electrons in the pipeline, the galvanized pipe is filled with electric tannin (mixture of bitumen and quartz powder) and kraft paper, second oil two paper or three oil three papers before installation. After head welding, it should be treated equally. The insulation resistance should be not less than 0.5 Mn, and check if the pipe is punctured with low voltage 380V/220V.
4. On the side of the gas transmission pipeline, a distance of 50cm, a tens of meters of grounded galvanized l” pipe grounding tape shall be embedded in the same trench, and a galvanized iron tape shall be introduced into the testing station.
5. If the gas or natural gas leaks and breaks through the insulating layer under pressure, the electrons enter the land, return to the grounding zone and enter the detection instrument, and immediately reflect it from the instrument. The leak distance and the position of the pipe fault can be organized to repair the manpower.

GNEE PACKAGING AND SHIPPING

There are probably hundreds of different methods for packing a pipe, and most of them have merit, but there are two principles that are vital for any method to work prevent rusting and Sea transportation security.Our packing can meet any needs of the customers.

 

 

 

 

We're well-known as one of the leading galvanized steel pipe manufacturers and suppliers in China. If you're going to buy discount galvanized steel pipe in stock, welcome to get quotation and free sample from our factory. Also, customized service is available.