Hot Dipped Galvanized (HDG) Steel Pipe
-
Heavy Zinc Coating
-
Long-Term Protection
-
Full Coverage
Share:
Detailed Description of Hot Dipped Galvanized Steel Pipe
Hot-dip galvanizing is an effective method of providing corrosion protection. There are three major manufacturers' processes used in the hot-dip galvanizing operation: surface preparation, galvanizing, and post-treatment. The base steel pipe starts with a thorough cleaning using a degreaser, a pickling process (to remove mill scale and rust), and fluxing. The clean pipe is then completely submerged into a kettle of molten zinc. While the pipe is submerged, molten zinc reacts with the iron in the steel to form zinc-iron alloy layers; additionally, pure zinc forms a layer after the previous zinc-iron alloy layers, resulting in a layered structure with uniform protection. This structure provides excellent abrasion resistance and cathodic (or sacrificial) protection so that if the galvanized coating is scratched, the surrounding zinc protects the exposed steel base.
Key Parameters for Hot Dipped Galvanized Steel Pipe
Parameter |
Details |
Manufacturing Process |
Hot-dip galvanizing of ERW or Seamless pipes |
Galvanizing Standard |
ASTM A123, ISO 1461, AS/NZS 4680, |
Base Pipe Standard |
ASTM A53, EN 10219, GB/T 3091 |
Steel Grade |
Q235, Q345, Gr.A, Gr.B, S235, S355 |
Size Range (OD) |
21.3mm - 914.4mm (1/2" - 10") |
Wall Thickness (WT) |
1.5mm - 10mm |
Zinc Coating Thickness |
Average ≥45µm, varies with steel thickness as per standard |
Surface Finish |
Bright with crystalline zinc pattern (spangle), can be smooth |
Pipe Ends |
Plain, Beveled, Threaded with Couplings |
Hot Dipped Galvanized Pipe Specifications
Standard: ASTM A53
Standard: ASTM A53 | ||||||
OD（in/mm） |
WT（mm） |
|||||
Size |
Inch |
mm |
SCH10 |
SCH20 |
SCH40 |
SCH80 |
DN15 |
1 |
21.3 |
- |
- |
2.77 |
3.73 |
DN20 |
3 |
26.7 |
- |
- |
2.87 |
3.91 |
DN25 |
1" |
33.4 |
- |
- |
3.38 |
4.55 |
DN32 |
2004/1/1 |
42.2 |
- |
- |
3.56 |
4.85 |
DN40 |
2002/1/1 |
48.3 |
- |
- |
3.68 |
5.05 |
DN50 |
2" |
60.3 |
- |
- |
3.91 |
5.54 |
DN65 |
2002/2/1 |
73 |
- |
- |
5.16 |
7.01 |
DN80 |
3" |
88.9 |
- |
- |
5.49 |
7.62 |
DN90 |
2002/3/1 |
101.6 |
- |
- |
5.74 |
8.08 |
DN100 |
4" |
114.3 |
- |
- |
6.02 |
8.58 |
DN125 |
5" |
141.3 |
- |
- |
6.55 |
9.53 |
DN150 |
6" |
168.3 |
- |
- |
7.11 |
10.97 |
DN200 |
8" |
219.1 |
- |
6.35 |
8.18 |
12.7 |
DN250 |
10" |
273.1 |
- |
6.35 |
9.27 |
15.09 |
DN300 |
12" |
323.9 |
- |
6.35 |
10.31 |
17.48 |
DN350 |
14" |
355.5 |
6.35 |
7.92 |
11.13 |
19.05 |
DN400 |
16" |
406.4 |
6.35 |
7.92 |
12.7 |
21.44 |
DN450 |
18" |
457.2 |
6.35 |
7.92 |
14.27 |
23.83 |
DN500 |
20" |
508 |
6.35 |
9.53 |
15.09 |
26.19 |
DN550 |
22" |
558.8 |
6.35 |
9.53 |
- |
28.58 |
DN600 |
24" |
609.6 |
6.35 |
9.53 |
17.48 |
30.96 |
DN650 |
26" |
660.4 |
7.92 |
12.7 |
- |
- |
DN700 |
28" |
711.6 |
7.92 |
12.7 |
- |
- |
DN750 |
30" |
762 |
7.92 |
12.7 |
- |
- |
DN800 |
32" |
812.8 |
7.92 |
12.7 |
17.48 |
- |
DN850 |
34" |
863.6 |
7.92 |
12.7 |
17.48 |
- |
DN900 |
36" |
914.4 |
7.92 |
12.7 |
19.05 |
- |
Standard: BS 1387-1985/BS EN10255
Type |
|
Outside Diameter |
|
Weight |
Pieces Per Bundle |
||||||||
Size |
Minimum |
Maximum |
Wall Thickness |
Plain Ends |
Screwdc & socketed |
||||||||
Light |
inch |
DN |
inch |
mm |
inch |
mm |
inch |
mm |
inch |
mm |
inch |
mm |
|
1/2“ |
15 |
0.825 |
21.0 |
0.841 |
21.4 |
0.079 |
2.0 |
0.289 |
0.95 |
0.291 |
0.956 |
153 |
|
3/4” |
20 |
1.041 |
26.4 |
1.059 |
26.9 |
0.091 |
2.3 |
0.421 |
1.38 |
0.424 |
1.390 |
127 |
|
1“ |
25 |
1.309 |
33.2 |
1.328 |
33.8 |
0.102 |
2.6 |
0.603 |
1.98 |
0.610 |
2.000 |
91 |
|
1 1/4” |
32 |
1.650 |
41.9 |
1.670 |
42.5 |
0.102 |
2.6 |
0.774 |
2.54 |
0.783 |
2.570 |
61 |
|
1 1/2“ |
40 |
1.882 |
47.8 |
1.903 |
48.4 |
0.114 |
2.9 |
0.985 |
3.23 |
0.997 |
3.270 |
61 |
|
2” |
4 |
2.347 |
59.6 |
2.370 |
60.2 |
0.114 |
2.9 |
1.240 |
4.08 |
1.260 |
4.150 |
37 |
|
2 1/2“ |
65 |
2.960 |
75.2 |
2.991 |
76.0 |
0.126 |
3.2 |
1.740 |
5.71 |
1.780 |
5.830 |
37 |
|
3” |
80 |
3.460 |
87.9 |
3.491 |
88.7 |
0.126 |
3.2 |
2.050 |
6.72 |
2.100 |
6.590 |
19 |
|
4“ |
100 |
4.450 |
110.0 |
4.481 |
113.9 |
0.142 |
3.6 |
2.970 |
9.75 |
3.050 |
10.000 |
19 |
|
Medium |
1/2“ |
15 |
0.831 |
21.1 |
0.856 |
21.7 |
0.102 |
2.6 |
0.369 |
1.21 |
0.372 |
1.220 |
127 |
3/4” |
20 |
1.047 |
26.6 |
1.072 |
27.2 |
0.102 |
2.6 |
0.475 |
1.56 |
0.479 |
1.570 |
101 |
|
1“ |
25 |
1.316 |
33.4 |
1.346 |
34.2 |
0.126 |
3.2 |
0.735 |
2.41 |
0.741 |
2.430 |
61 |
|
1 1/4” |
32 |
1.657 |
42.1 |
1.687 |
42.9 |
0.126 |
3.2 |
0.945 |
3.10 |
0.954 |
3.130 |
51 |
|
1 1/2“ |
40 |
1.889 |
48.0 |
1.919 |
48.8 |
0.126 |
3.2 |
1.090 |
3.57 |
1.100 |
3.610 |
44 |
|
2” |
50 |
2.354 |
59.8 |
2.394 |
60.8 |
0.142 |
3.6 |
1.530 |
5.03 |
1.550 |
5.100 |
29 |
|
2 1/2“ |
65 |
2.969 |
75.4 |
3.014 |
76.6 |
0.142 |
3.6 |
1.960 |
6.43 |
1.990 |
6.550 |
24 |
|
3” |
80 |
3.469 |
88.1 |
3.524 |
89.5 |
0.157 |
4.0 |
2.550 |
8.37 |
2.600 |
8.540 |
19 |
|
4“ |
100 |
4.459 |
113.3 |
4.524 |
114.9 |
0.177 |
4.5 |
3.720 |
12.20 |
3.810 |
12.500 |
14 |
|
5" |
125 |
5.461 |
138.7 |
5.535 |
140.6 |
0.197 |
5.0 |
5.060 |
16.60 |
5.210 |
17.100 |
10 |
|
6” |
150 |
6.460 |
164.1 |
6.539 |
166.1 |
0.197 |
5.0 |
6.000 |
19.70 |
6.190 |
20.300 |
7 |
|
Heavy |
1/2“ |
15 |
0.831 |
21.1 |
0.856 |
21.7 |
0.126 |
3.2 |
0.439 |
1.44 |
0.442 |
1.450 |
127 |
3/4” |
20 |
1.047 |
26.6 |
1.072 |
27.2 |
0.126 |
3.2 |
0.570 |
1.87 |
0.573 |
1.880 |
101 |
|
1“ |
25 |
1.316 |
33.4 |
1.346 |
34.2 |
0.157 |
4.0 |
0.896 |
2.94 |
0.902 |
2.960 |
61 |
|
1 1/4” |
32 |
1.657 |
42.1 |
1.687 |
42.9 |
0.157 |
4.0 |
1.160 |
3.80 |
1.170 |
3.830 |
51 |
|
1 1/2“ |
40 |
1.889 |
48.0 |
1.919 |
48.8 |
0.157 |
4.0 |
1.330 |
4.38 |
1.350 |
4.420 |
44 |
|
2” |
50 |
2.354 |
59.8 |
2.394 |
60.8 |
0.177 |
4.5 |
1.890 |
6.19 |
1.910 |
6.260 |
29 |
|
2 1/2“ |
65 |
2.969 |
75.4 |
3.014 |
76.6 |
0.177 |
4.5 |
2.420 |
7.93 |
2.450 |
8.050 |
24 |
|
3” |
80 |
3.469 |
88.1 |
3.524 |
89.5 |
0.197 |
5.0 |
3.140 |
10.30 |
3.200 |
10.500 |
19 |
|
4“ |
100 |
4.459 |
113.3 |
4.524 |
114.9 |
0.212 |
5.4 |
4.420 |
14.50 |
4.510 |
14.800 |
14 |
|
5" |
125 |
5.46 |
138.7 |
5.535 |
140.6 |
0.212 |
5.4 |
5.460 |
17.90 |
5.610 |
18.400 |
10 |
|
6” |
150 |
6.460 |
164.1 |
6.539 |
166.1 |
0.212 |
5.4 |
6.490 |
21.30 |
6.670 |
21.900 |
7 |
|
Standard: ANSI C80.3,UL797,TTIS 770-2533
Nomina Size |
Outside Diameter |
Nominal Inside Diameter |
Nominal Wall Thickness |
Length Without coupling |
Minmum Weight of Ten unit lengthes with coupling |
||||
inch |
inch |
mm |
inch |
mm |
inch |
mm |
mm |
1b |
kg/length |
1/2 |
0.840" |
21.3 |
0.632" |
16.1 |
0.104" |
2.64 |
3030 |
79.0 |
35.83 |
3/4 |
1.050" |
26.7 |
0.836" |
21.2 |
0.107" |
2.72 |
3030 |
105.0 |
47.63 |
1" |
1.315" |
33.4 |
1.063" |
27.0 |
0.126" |
3.20 |
3020 |
153.0 |
69.40 |
1 1/4" |
1.660" |
42.2 |
1.394" |
35.4 |
0.133" |
3.38 |
3020 |
201.0 |
91.17 |
1 1/2" |
1.900" |
48.3 |
1.624" |
41.2 |
0.138" |
3.51 |
3020 |
249.0 |
112.95 |
2" |
2.375" |
60.3 |
2.083" |
52.9 |
0.146" |
3.71 |
3020 |
332.0 |
150.60 |
2 1/2" |
2.875" |
73.0 |
2.489" |
63.2 |
0.193" |
4.90 |
3010 |
527.0 |
239.05 |
3" |
3.500" |
88.9 |
3.090" |
78.5 |
0.205" |
5.21 |
3010 |
682.6 |
309.63 |
3 1/2" |
4.000" |
101.6 |
3.570" |
90.7 |
0.215" |
5.46 |
3000 |
831.0 |
376.94 |
4" |
4.500" |
114.3 |
4.050" |
102.9 |
0.225" |
5.72 |
3000 |
972.3 |
441.04 |
5" |
5.563" |
141.3 |
5.073" |
128.9 |
0.245" |
6.22 |
3000 |
1313.6 |
595.85 |
6" |
6.625" |
168.3 |
6.093" |
154.8 |
0.266" |
6.76 |
3000 |
1745.3 |
791.67 |
Nomina Size |
Outside Diameter |
Nominal Inside Diameter |
NominalWall Thickness |
Length Without coupling |
Minmum Weight of Ten unit lengthes with coupling |
||||
inch |
inch |
mm |
inch |
mm |
inch |
mm |
mm |
1b |
kg/length |
1/2 |
0.840" |
21.34 |
0.632" |
16.05 |
0.104" |
2.64 |
3030 |
79.0 |
35.83 |
3/4 |
1.050" |
26.67 |
0.836" |
21.23 |
0.107" |
2.72 |
3030 |
105.0 |
47.63 |
1" |
1.315" |
33.40 |
1.063" |
27.00 |
0.126" |
3.20 |
3025 |
153.0 |
69.40 |
1 1/4" |
1.660" |
42.16 |
1.394" |
35.41 |
0.133" |
3.38 |
3025 |
201.0 |
91.17 |
1 1/2" |
1.900" |
48.26 |
1.624" |
41.25 |
0.138" |
3.51 |
3025 |
249.0 |
112.95 |
2" |
2.375" |
60.33 |
2.083" |
52.91 |
0.146" |
3.71 |
3025 |
332.0 |
150.59 |
2 1/2" |
2.875" |
73.03 |
2.489" |
63.22 |
0.193" |
4.90 |
3010 |
527.0 |
239.04 |
3" |
3.500" |
88.90 |
3.090" |
78.49 |
0.205" |
5.21 |
3010 |
682.6 |
309.62 |
3 1/2" |
4.000" |
101.60 |
3.570" |
90.68 |
0.215" |
5.46 |
3005 |
831.0 |
376.94 |
4" |
4.500" |
114.30 |
4.050" |
102.87 |
0.225" |
5.72 |
3005 |
972.3 |
441.03 |
5" |
5.563" |
141.30 |
5.073" |
128.85 |
0.245" |
6.22 |
2995 |
1313.6 |
595.85 |
6" |
6.625" |
168.28 |
6.093" |
154.76 |
0.266" |
6.76 |
2995 |
1745.3 |
791.67 |
Standard Number |
Applicable Products |
Core Features |
ASTM A123/A123M |
Iron and steel products, such as structural members, plates, pipes, bars, etc. |
The primary standard for hot-dip galvanized coatings on iron and steel products fabricated or manufactured, specifying coating thickness, finish, adherence, etc. |
ASTM A153/A153M |
Iron and steel hardware, such as bolts, nuts, washers, and other small accessories. |
Specifically for hot-dip galvanized coatings on iron and steel hardware, applicable to smaller product categories. |
ASTM A767/A767M |
Steel bars for concrete reinforcement. |
Provides specific requirements for galvanizing reinforcing steel bars (rebar) used in concrete structures. |
ASTM A780 |
Damaged hot-dip galvanized coatings. |
Provides approved methods and standards for repairing galvanized coatings damaged during welding, cutting, transportation, or installation. |
ASTM A143 |
Structural steel products. |
Provides safeguards and detection procedures against embrittlement (hydrogen embrittlement) of structural steel products during the hot-dip galvanizing process. |
ASTM A384 / A385 |
Steel assemblies. |
Provides safeguards against warpage and distortion of steel assemblies during hot-dip galvanizing and guidance on providing high-quality zinc coatings. |
Main Application Areas for Hot Dipped Galvanized Pipe
HDG pipe is chosen for many uses because of its exceptional durability and resistance to corrosion. Some common applications include:
● Construction & Infrastructure: For scaffolding systems, guardrails, handrails, light poles, structural support for bridges and buildings.
● Water & Fluid Transport: For municipal water supply, drainage systems, fire sprinkler systems, and irrigation pipes in agriculture.
● Agriculture: As the framework for agricultural greenhouses and animal pens.
● Energy & Communication: Used for electrical conduit, cable trays, and communication towers.
● Outdoor Structures: For fencing, sign posts, and general outdoor framework.
Advantages of Hot Dipped Galvanized Steel Pipe
● Long Life: Provides for decades of maintenance-free performance in most environments.
● Total Protection: Coats the whole pipe including edges, corners and the internal surface.
● High Toughness: The zinc-iron alloy layers are metallurgically bonded and are highly resistant to mechanical damage.
● Reliability: The process is easy to control and has the potential to provide consistent, measurable thicknesses of coating.
● Cost Effectiveness: Has the lowest total cost over the long-term compared to most other protection coatings.
