Galvanized Steel Pipe

Specification

Item	Galvanized steel pipe
Place of origin	Tianjin, China
Standard	ASTM, EN, JIS, GB, DIN
Technique	ERW, LSAW
Material	Q195/Q235/Q345(S235JR/S275JR/S355JR), A53 Grade A/B,A500 Grade A/B/C
Section Shape	Square tubes, rectangular tubes, round tubes, elliptical tubes
Surface Treatment	Hot Dipped Galvanized
Zinc layer	30-275g/㎡
Thickness	1mm-30mm
Length	2-12m, customizable
Certificate	CE, SGS, ISO9001, BV, API
Processing Service	Cutting, welding
Trade Terms	FOB/CIF/CFR/EXW

Features Of Galvanized Steel Pipe

Applications of GI Pipes

• Building Structures: Scaffolding pipes, fire-fighting pipes, I-beam and truss support pipes, as well as streetlight poles and traffic sign poles.
• Fluid Transportation: Water supply and drainage pipes, fire sprinkler pipes, low-pressure gas transportation, oil and gas transportation, and agricultural irrigation water pipes.
• Electrical Applications: Common JDG and KBG conduits, electrical wiring conduits, and conductors for grounding devices.
• Industrial Applications: Warehouse racks, conveyor rails, ventilation and dust extraction ducts, and safety guardrail posts.

Mechanical Properties Comparison Table

Standard	Grade	Tensile Strength	Yield Strength	Elongation
ASTM A53	Grade A	330 – 480 MPa	≥ 170 MPa	≥ 30%
ASTM A53	Grade B	415 – 550 MPa	≥ 240 MPa	≥ 20%
ASTM A500	Grade B	≥ 435 MPa	≥ 290 MPa	≥ 20%
ASTM A500	Grade C	≥ 483 MPa	≥ 317 MPa	≥ 23%
EN 10219	S235JR	360 – 510 MPa	≥ 235 MPa	≥ 26%
EN 10219	S275JR	410 – 560 MPa	≥ 275 MPa	≥ 22%
EN 10219	S355JR	470 – 630 MPa	≥ 355 MPa	≥ 21%
GB/T 3091	Q195	315 – 430 MPa	≥ 195 MPa	≥ 33%
GB/T 3091	Q235B	370 – 500 MPa	≥ 235 MPa	≥ 26%
GB/T 3091	Q345B	470 – 630 MPa	≥ 345 MPa	≥ 21%

ASTM A53 and GB/T3091 corresponding specification table

NPS	DN	OD, mm	Astm Sch40	ASTM Sch80	GB/T3091 Standard	GB/T3091 Thickened
1/2″	DN15	21.34	2.11	3.73	2.75	3.25
3/4″	DN20	26.67	2.87	4.19	2.75	3.25
1″	DN25	33.40	2.77	5.49	3.25	3.75
1-1/2″	DN40	48.26	3.68	6.02	3.50	4.00
2″	DN50	60.33	3.91	5.54	3.50	4.00
3″	DN80	88.90	5.49	8.38	4.00	4.50
4″	DN100	114.30	6.02	10.16	4.00	4.50
–	DN32	42.4	–	–	3.25	3.75
–	DN65	76.1	–	–	3.75	4.25
–	DN150	168.3	–	–	4.50	5.00
–	DN200	219.1	–	–	4.50	5.50

Note:

NPS: American standard nominal diameter, DN: Chinese standard nominal diameter, OD: actual outer diameter. Sch 40: Commonly used wall thickness grade in the American standard, corresponding to “ordinary wall thickness” in the Chinese standard.

Wall Thickness Representation Method

Hot-dip galvanizing involves immersing the pipe in molten zinc. While more expensive than cold-dip galvanizing, it offers superior corrosion resistance. All of our galvanized pipes are hot-dip galvanized.

American Standard – SCH

SCH is an abbreviation for Schedule, a wall thickness designation method in the American standard ASME B36.10/B36.19. Besides SCH40 and SCH80, there are also SCH10, SCH20, SCH30, SCH60, SCH100, SCH120, SCH140, SCH160, etc. Under the same NPS (Net Size Per Second), the higher the SCH value, the thicker the wall.

National Standard – DN

DN is an abbreviation for Nominal Diameter, a common designation used in Chinese national standards (and some international standards) to identify pipe diameter. The number following it does not represent the actual size, but only the nominal size designation.

1. Classification By Coating Process

• Hot-dip galvanized pipe (HDG): The steel pipe is immersed in molten zinc at approximately 450°C. The zinc layer is thicker, the surface is relatively rough, and the coating adhesion is strong.
• Electro-galvanized pipe (pre-galvanized): Before pipe forming, a thin layer of zinc is deposited using an electrolytic method. The coating is thinner (10-30μm), the surface is smooth, and the tolerances are precise.

2. Classification By Cross-Sectional Shape

• Galvanized round tubes: The most common type (outer diameter: 1/2″ – 8″). Used for water supply, gas supply, and structural support.
• Galvanized square tubes: Side lengths 10mm-200mm. Uniform stress distribution, ideal for building frames and handrails.
• Galvanized rectangular tubes: Sizes such as 20×40mm or 50×100mm. Widely used in curtain walls and machinery.
• Galvanized shaped tubes: Custom shapes (elliptical, hexagonal) for decorative railings or specific equipment.

3. Classification By Welding Process

• ERW galvanized pipe (resistance welded): Rolled from steel coils and welded using high-frequency current. High efficiency and uniform wall thickness.
• LSAW galvanized pipe (longitudinal submerged arc welded): Welded longitudinally. Features thick walls and high pressure resistance, suitable for large-diameter industrial applications.
• Spiral-welded galvanized pipe: Welded from steel strips in a spiral. High flexibility, suitable for long-distance pipeline transportation.

Formula For Weight Of Galvanized Pipe

1. Galvanised Round Pipe Weight Formula

Weight = (Outer Diameter – Wall Thickness) × Wall Thickness × 0.02466

2. Galvanised Square Pipe Weight Formula

Weight = (2Side Length – 2Wall Thickness) × Wall Thickness × 0.00785

3. Galvanised Rectangular Pipe Weight Formula

Weight = (Length of Long Side + Length of Short Side – 2Wall Thickness) × 2 × T × 0.00785

4. Galvanised Triangle Pipe Weight Formula

Weight = (A + B + C – 2T) × Wall Thickness × 0.00785（A,B,C：Lengths of the three sides）

5. Galvanised Oval Pipe Weight Formula

Weight = (Major axis (Length) + Minor axis (Width) – 2Thickness) × Thickness × 0.0222

FAQs

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Glory Steel Plant, located in Tianjin, China, is an ISO 9001, ISO 14001, and CE certified factory with an annual output of 100,000 tons. We specialize in producing galvanized pipes, stainless steel pipes, and alloy steel pipes. With our high-quality products and services, we export to over 120 countries.