Description

Galvanized steel pipes are classified into hot-dip galvanized steel pipes and cold-dip galvanized steel pipes (electro-galvanized) according to their manufacturing process. The former has strong corrosion resistance and a long service life; the latter has a thinner coating and is prone to peeling.

1. Hot-dip galvanized steel pipes: A zinc-iron alloy layer is formed by the reaction of molten zinc with the iron substrate. The coating is thick (≥500 g/m²), with strong adhesion, good corrosion resistance, and a long service life. It is suitable for fire protection, power, highways, structural support, and some hot water pipelines. They are usually welded steel pipes (straight seam or spiral seam), but hot-dip galvanized seamless pipes are also available.

2. Cold-galvanized steel pipe: This type uses an electroplating process, resulting in a coating of only 10–50 g/m², lacking alloy bonding, prone to peeling, and with poor corrosion resistance. Due to the low stability of the zinc layer and hygiene risks, it is strictly prohibited for fluid transportation (water/gas). Currently, it is only occasionally used in non-load-bearing structural components or for later repairs (not mainstream); it has been phased out and is not permitted in formal engineering projects.

3. According to shape, galvanized steel pipes can also be divided into galvanized welded pipes (common), galvanized seamless pipes (for high-pressure fluids/machinery), galvanized square steel pipe/galvanized rectangular pipes (structural/decorative), and galvanized conduit (KBG/JDG/SC type, for electrical protection). However, the core classification remains based on hot-dip/cold-dip galvanizing processes. Currently, in new construction, galvanized steel pipes (especially hot-dip galvanized) are gradually being replaced by stainless steel and plastic composite pipes, but they are still widely used in industrial, fire protection, and support applications.

Applications of Galvanized Steel Pipe:

Galvanized steel pipe is widely used in construction, industry, and agriculture.

1. Construction and Assembly: Galvanized steel pipes are commonly used in scaffolding, railings, steel structure factories, and are also favored for the frames of rural greenhouses due to their sturdiness and durability.

2. Piping: Primarily used for transporting gas, heating water, fire-fighting water, and industrial oil. Its corrosion resistance makes it suitable for underground installations or damp environments.

3. Machinery Manufacturing: Used in automobile chassis, machinery frames, and electrical cable trays to protect internal structures from rust.

Specifications of Galvanized Steel Pipe:

Galvanized Round Steel Pipe Steel Tube
Stabdaed:API 5L,API 5CT,ASTM A53,ASTM A500,GB9711.1 Application:To be used for conveying gas,water,and petroleum for oil and natural gas industries and use for the structural steel pipes purpose Main Steel Tube Grade:GR.A,GR.B,GR.C,Q195,Q235B,Q345B and so on.
INCH	OD	Strandard Wall Thickness
	(MM)	SCH 10WT	SCH 20WT	SCH 40WT	SCH 60WT	SCH 80WT	SCH 100WT	SCH 160WT	XXS
		(mm)	(mm)	(mm）	(mm)	（mm)	(mm)	（mm)	(mm)
1/4”	13.7			2.24		3.02
3/8”	17.1			2.31		3.2
1/2”	21.3	2.11		2.77		3.73		4.78	7.47
3/4″	26.7	2.11		2.87		3.91		5.56	7.82
1″	33.4	2.77		3.38		4.55		6.35	9.09
1-1/4″	42.2	2.77		3.56		4.85		6.35	9.7
1-1/2″	48.3	2.77		3.68		5.08		7.14	10.15
2″	60.3	2.77		3.91		5.54		8.74	11.07
2-1/2″	73	3.05		5.16		7.01		9.53	14.02
3″	88.9	3.05		5.49		7.62		11.13	15.24
3-1/2″	101.6	3.05		5.74		8.08
4″	114.3	3.05	4.5	6.02		8.56		13.49	17.12
5″	141.3	3.4		6.55		9.53		15.88	19.05
6″	168.3	3.4		7.11		10.97		18.26	21.95
8″	219.1	3.76	6.35	8.18	10.31	12.7	15.09	23.01	22.23
10″	273	4.19	6.35	9.27	12.7	15.09	18.26	28.58	25.4
12″	323.8	4.57	6.35	10.31	14.27	17.48	21.44	33.32	25.4
14″	355	6.35	7.92	11.13	15.09	19.05	23.83	36.71
16″	406	6.35	7.92	12.7	16.66	21.44	26.19	40.49
18″	457	6.35	7.92	14.27	19.05	23.83	29.36	46.24
20″	508	6.35	9.53	15.09	20.62	26.19	32.54	50.01
22″	559	6.35	9.53		22.23	28.58	34.93	54.98
24″	610	6.35	9.53	17.48	24.61	30.96	38.89	59.54
26″	660	7.92	12.7
28″	711	7.92	12.7
30″	762	7.92	12.7
32″	813	7.92	12.7	17.48
34″	863	7.92	12.7	17.48
36″	914	7.92	12.7	19.05
38″	965
40″	1016
42″	1066
44″	1117
46″	1168
48″	1219

Standards and Classifications

Product name	Hot Dip Galvanized Round Steel Pipe / GI Pipe Pre Galvanized Steel Pipe Galvanized Tube For Construction / Square rectangular galvanized steel pipes
Material	10#, 20#, 45#, 16Mn, A53(A,B), Q235, Q345, Q195, Q215, St37, St42, St37-2, St35.4, St52.4, ST35, S235JR, GR.B-D, STK400, STK500, S235GT
Wall Thickness	1MM~12MM
Outer Diameter	20MM~508MM
Length	1m-14m,5.8m,6m,10m-12m,12m or as customer’s actual requirements
Standard	API 5L, ASTM A53-2007, ASTM A671-2006, ASTM A252-1998, ASTM A450-1996, ASME B36.10M-2004, ASTM A523-1996, BS 1387, BS EN10296, BS6323, BS 6363, BS EN10219, GB/T 3091-2001, GB/T 13793-1992, GB/T9711
Zinc Coating	30-275g/m2
Grade	10#-45#, 16Mn, A53-A369, Q195-Q345, ST35-ST52,Grade A, Grade B, Grade C
Technique	Hot Dip Galvanized Round Steel Pipe
Packing	Bundle, or with all kinds of colors PVC or as your requirements
Pipe Ends	Plain end/Beveled,protected by plastic caps on both ends, cut quare,grooved,threaded and coupling,etc.
Surface Treatment	1. Galvanized 2. PVC,Black and color painting 3. Transparent oil,anti-rust oil 4. According to clients requirement
Application	1. Fence, greenhouse, door pipe,greenhouse 2. Low pressure liquid, water, gas, oil, line pipe 3. For both indoor and outdoor the building construction