Pre-Galvanized Steel Pipes are carbon steel pipes coated with a zinc layer during the manufacturing process, offering cost-effective corrosion resistance. Compliant with ASTM A53 and A123 standards, these pipes are ideal for furniture manufacturing, construction frameworks, and fencing, providing a minimum tensile strength of 330 MPa and a zinc coating thickness of 0.6-1.0 oz/ft² (183-305 g/m²).

The pre-galvanizing process involves coating steel strips with zinc before forming them into pipes via electric resistance welding (ERW). This ensures uniform zinc coverage, though thinner than hot-dip galvanizing, making Pre-Galvanized Steel Pipes suitable for less corrosive environments. Available in sizes from DN15 (1/2”) to DN150 (6”) with wall thicknesses from 0.8 to 3.0 mm, and lengths from 5.8 to 12 meters, these pipes meet diverse project requirements. Surface treatments like passivation enhance durability, and threaded or plain ends facilitate easy installation.

These pipes undergo rigorous testing, including tensile, bending, and coating thickness tests, to ensure compliance with ASTM standards. The zinc coating provides a protective barrier against rust, making Corrosion-Resistant Steel Pipes suitable for indoor and mildly corrosive outdoor applications. Their lightweight design and welded construction support applications like greenhouse structures and automotive components.

Compared to hot-dip galvanized or stainless steel pipes, Pre-Galvanized Steel Pipes are more affordable but offer less robust corrosion resistance, requiring maintenance in harsh environments. Their versatility and lifespan (20-30 years) make them a preferred choice for light structural supports and cost-sensitive projects.

Pre-Galvanized Steel Pipes address challenges like corrosion, cost constraints, and structural versatility, delivering reliable solutions for industrial, residential, and agricultural applications.

What is pre galvanized steel pipe?

Pre-galvanized steel pipe is a type of steel pipe that has been coated with a layer of zinc before it is formed into its final shape. This process provides corrosion resistance and enhances the durability of the pipe.

Steel tubes that are formed and galvanized afterwards are sometimes referred to as post-galvanized steel tubes, but hot-dipped steel tubes is a more commonly used expression.

Galvanized steel pipe or galvanized steel tube is the most popular type of galvanized steel tube manufacturing because the equipment required for manufacturing is relatively inexpensive and the process is highly scalable. Unlike hot-dip steel tube, the time required for galvanizing the steel sheet is short, so the alloy layer in which iron and zinc are mixed is small and the pure zinc layer is thick.

However, since the zinc applied to the steel sheet is removed by the heat upon welding the pre-galvanized steel tube, re-sealing the exposed steel on the outside surface with zinc thermal spray is a required post-treatment process. This also means that the welding seam on the inside of the steel tube is not galvanized. The sacrificial anode properties of zinc allow for leaving the inner welding seam exposed without reducing the corrosion resistance and longevity of the product.

Pre-galvanization, also known as mill galvanization, involves passing a steel sheet through molten zinc. After this process, the sheet is cut to the desired size and recoiled. During pre-galvanization, a specific thickness of zinc coating is applied to the entire sheet. For instance, pre-galvanized Z275 steel has a zinc coating of 275 grams per square meter. One notable advantage of pre-galvanized steel compared to hot-dip galvanized steel is its improved appearance. Additionally, it tends to be more cost-effective. Pre-galvanized materials find application in a wide range of products, including conduit, lip, and open channels.

What is the difference between pre galvanized steel and galvanized steel?

As hot dipped galvanization requires dipping the whole steel/metals into the molten vat of zinc, the galvanized steel coming out from this process has a continuous coating over the surface. Pre-galvanizing is performed at the first stage before the sheets are cut into sizes and pieces so the cut edges are not coated.

Pre galvanized Rectangular tubes are the industry standard for fence framework, Contractors, architects, engineers. Architects and landscape architects have used steel fencing to design a variety of shelters, lighting standards and decorative sculptures for street-scapes, parks, bus and light rail stops, shopping centers, malls, sports stadiums, office buildings, parking lots and other facilities. Steel fence post are carefully designed with clean lines, structural integrity and ease of installation. These fences are available in variety of heights and widths in multiple configurations.

British Standard (BS1387-85) Thin thickness pipe specification
ND		Outside Diameter (mm)		W.T.	Weight of Black Pipe (kg/m)
Nominal Size (DN)	Screw Identifiers	Maximum	Minimum	Thickness	Plain end pipe	Threaded and With Coupler
15	1/2	21.4	21.0	2.0	0.947	0.956
20	3/4	26.9	26.4	2.3	1.38	1.39
25	1	33.8	33.2	2.6	1.98	2.00
32	11/4	42.5	41.9	2.6	2.54	2.57
40	11/2	48.4	47.8	2.9	3.23	3.27
50	2	60.2	59.6	2.9	4.08	4.15
65	21/2	76.0	75.2	3.2	5.71	5.83
80	3	88.7	87.9	3.2	6.72	6.89
100	4	113.9	113.0	3.6	9.75	10.0

Properties of Pre-Galvanized Steel Pipe

The properties of galvanized steel are a unique combination that make it ideal for use in interior and exterior applications such as car bodies, appliances, nuts and bolts, roofs, and rebar.

Corrosion Resistance
Surface Appearance
Formability
Durability
Recyclable

Pre-Galvanized Steel Pipe Standard Specifications

Chemical Composition of Pre-Galvanized Steel Pipe
Grade	C (% max)	Mn (% max)	P (% max)	S (% max)	Cu (% max)
Grade A	0.25	0.95	0.05	0.045	0.40
Grade B	0.30	1.20	0.05	0.045	0.40

The zinc coating (80-100 microns) enhances the corrosion resistance of Pre-Galvanized Steel Pipe , protecting the carbon steel base in harsh environments. The chemical composition ensures weldability and durability for

Mechanical Properties of Pre-Galvanized Steel Pipe
Grade	Tensile Strength (min, MPa)	Yield Strength (min, MPa)	Elongation (min, %)
Grade A	330	205	28
Grade B	415	240	30

These properties ensure Pre-Galvanized Steel Pipe eliver robust performance in structural and high-pressure applications.

Comparison of Hot-Dip Galvanized Pipes with Other Pipes
Feature	Hot-Dip Galvanized Pipe	Pre-Galvanized Pipe	Stainless Steel Pipe
Coating	Zinc (80-100 microns)	Zinc (thinner, coil-coated)	None (inherent corrosion resistance)
Corrosion Resistance	Excellent (sacrificial anode)	Moderate (weaker at welds)	Superior (no coating needed)
Cost	Cost-effective	Lower initial cost	Higher cost
Lifespan	Up to 50 years	20-30 years	50+ years
Applications	Water, gas, construction	Light structural, fencing	Chemical, marine, hygienic

Hot-Dip Galvanized Pipes offer distinct advantages over pre-galvanized and stainless steel pipes.

Chemical Composition of Stainless Hollow Sections (Grades 304, 304L, 316, 316L per ASTM A554/A312)
Grade	C (% max)	Mn (% max)	Si (% max)	P (% max)	S (% max)	Cr (%)	Ni (%)	Mo (%)	N (% max)
304	0.08	2.00	1.00	0.045	0.030	18.0-20.0	8.0-11.0	-	0.10
304L	0.03	2.00	1.00	0.045	0.030	18.0-20.0	8.0-12.0	-	0.10
316	0.08	2.00	1.00	0.045	0.030	16.0-18.0	10.0-14.0	2.0-3.0	0.10
316L	0.03	2.00	1.00	0.045	0.030	16.0-18.0	10.0-14.0	2.0-3.0	0.10

The low carbon content in 304L and 316L enhances weldability, while molybdenum in 316 and 316L improves resistance to pitting and crevice corrosion, making Pre-Galvanized Steel Pipe ideal for harsh environments.

Mechanical Properties of Stainless Hollow Sections (Grades 304, 304L, 316, 316L per ASTM A554/A312)
Grade	Tensile Strength (min, MPa)	Yield Strength (min, MPa)	Elongation (min, %)	Hardness (max, HB)	Hardness (max, HRB)
304	515	205	40	201	92
304L	485	170	40	201	92
316	515	205	40	217	95
316L	485	170	40	217	95

These mechanical properties make Pre-Galvanized Steel Pipe suitable for applications requiring high strength and corrosion resistance, such as architectural structures, marine environments, and chemical processing.