Tianjin Brisk Steel is one of the manufacturers of ASTM A53 / A53M‑24 Type‑E ERW Black Varnish Coated Carbon Steel Pipe in China. Our products are mainly exported to the Middle East, Southeast Asia, Europe, New Zealand, and other regions.If you would like to learn more about our products, feel free to contact us and send your purchase list.
Product Introduction
- ERW: Electric‑Resistance‑Welded, high‑frequency resistance welded pipe (Type‑E under ASTM A53)
- Black Varnish: Thin black anti‑rust varnish sprayed on outer surface, temporary rust‑proof coating for ocean shipment, NOT hot‑dip galvanized coating
- Base pipe: Carbon steel welded pipe, black bare pipe substrate before varnish spraying
Size Range & Tolerance
Dimension Tolerance
- Outer Diameter: NPS 1/2"‑24" (21.3mm‑609.6 mm)
- Wall‑thickness Schedule: SCH10, SCH40(STD), SCH80(XS), SCH160
- OD tolerance: ±1%
- Wall thickness tolerance: ±10% of nominal wall (per ASTM A53)
- Available Length: 5.8m, 6m, 11.8m, 12m; SRL/DRL random lengths, custom‑cut length acceptable
(NPS nominal size + SCH wall‑thickness schedule)
| Nominal Pipe Size(NPS) | Outside Diameter | Nominal Wall Thickness | |||||||||||||
| DN | Inch | mm | SCH10 | SCH20 | SCH30 | SCH40 | SCH60 | SCH80 | SCH100 | SCH120 | SCH140 | SCH160 | STD | XS | XXS |
| 6 | 1/8" | 10.3 | - | - | - | 1.73 | - | 2.42 | - | - | - | - | 1.73 | 2.41 | - |
| 8 | 1/4" | 13.7 | - | - | - | 2.24 | - | 3.02 | - | - | - | - | 2.24 | 3.02 | - |
| 10 | 3/8" | 17.1 | - | - | - | 2.31 | - | 3.2 | - | - | - | - | 2.31 | 3.2 | - |
| 15 | 1/2" | 21.3 | - | - | - | 2.77 | - | 3.73 | - | - | - | 4.78 | 2.77 | 3.73 | 7.47 |
| 20 | 3/4" | 26.7 | - | - | - | 2.87 | - | 3.91 | - | - | - | 5.56 | 2.87 | 3.91 | 7.82 |
| 25 | 1" | 33.4 | - | - | - | 3.38 | - | 4.55 | - | - | - | 6.35 | 3.38 | 4.55 | 9.09 |
| 32 | 11/4" | 42.2 | - | - | - | 3.56 | - | 4.85 | - | - | - | 6.35 | 3.58 | 4.85 | 9.7 |
| 40 | 11/2" | 48.3 | - | - | - | 3.68 | - | 5.05 | - | - | - | 7.14 | 3.68 | 5.08 | 10.15 |
| 50 | 2" | 60.3 | - | - | - | 3.91 | - | 5.54 | - | - | - | 8.74 | 3.91 | 5.54 | 11.07 |
| 65 | 21/2" | 73 | - | - | - | 5.16 | - | 7.01 | - | - | - | 9.53 | 5.16 | 7.01 | 14.02 |
| 80 | 3" | 88.9 | - | - | - | 5.49 | - | 7.62 | - | - | - | 11.13 | 5.49 | 7.52 | 15.24 |
| 90 | 31/2" | 101.6 | - | - | - | 5.74 | - | 8.08 | - | - | - | - | 5.74 | 8.08 | - |
| 100 | 4" | 114.3 | - | - | - | 6.02 | - | 8.58 | - | 11.13 | - | 13.49 | 6.02 | 8.56 | 17.12 |
| 125 | 5" | 141.3 | - | - | - | 6.55 | - | 9.53 | - | 12.7 | - | 15.88 | 6.55 | 9.53 | 18.05 |
| 150 | 6" | 168.3 | - | - | - | 7.11 | - | 10.97 | - | 14.27 | - | 18.26 | 7.11 | 10.97 | 21.95 |
| 200 | 8" | 219.1 | - | 6.35 | 7.04 | 8.18 | 10.31 | 12.7 | 15.09 | 18.26 | 20.62 | 23.01 | 8.18 | 12.7 | 22.23 |
| 250 | 10" | 273.1 | 6.35 | 7.8 | 9.27 | 12.7 | 15.09 | 18.26 | 21.44 | 25.4 | 28.58 | 9.27 | 12.7 | 25.4 | |
| 300 | 12" | 323.9 | - | 6.35 | 8.38 | 10.31 | 14.27 | 17.48 | 21.44 | 25.4 | 28.58 | 33.32 | 9.53 | 12.7 | 25.4 |
| 350 | 14" | 355.6 | 6.35 | 7.92 | 9.53 | 11.13 | 15.09 | 19.05 | 23.83 | 27.79 | 31.75 | 35.71 | 9.53 | 12.7 | - |
| 400 | 16" | 406.4 | 6.35 | 7.92 | 9.53 | 12.7 | 16.66 | 21.44 | 26.19 | 30.96 | 36.53 | 40.49 | 9.53 | 12.7 | - |
| 450 | 18" | 457.2 | 6.35 | 7.92 | 11.13 | 14.27 | 19.05 | 23.83 | 29.36 | 34.93 | 39.67 | 45.24 | 9.53 | 12.7 | - |
| 500 | 20" | 508 | 6.35 | 9.53 | 12.7 | 15.09 | 20.62 | 26.19 | 32.54 | 38.1 | 44.45 | 50.01 | 9.53 | 12.7 | - |
| 550 | 22" | 558.8 | 6.35 | 9.53 | 12.7 | - | 22.23 | 28.58 | 34.93 | 41.28 | 47.63 | 53.98 | 9.53 | 12.7 | - |
| 600 | 24" | 609.6 | 6.35 | 9.53 | 14.27 | 17.48 | 24.61 | 30.96 | 38.89 | 46.02 | 52.37 | 59.54 | 9.53 | 12.7 | - |
ERW PROCESS
Steel coil slitting → Roll forming → High‑frequency ERW welding → Remove inner & outer weld bead → Weld seam annealing → Sizing & straightening → Fixed‑length cutting → NDT eddy‑current test for weld seam → Hydrostatic pressure test → Flattening test / Bend test → Surface cleaning → Black varnish spraying → Marking → Bundling & export packing
Surface: Black Varnish Coating Detailed
1. Coating type: Thin liquid black anti‑rust varnish, spray‑coated outside the pipe
2. Function: Temporary anti‑rust protection during sea transport & warehouse storage, avoid surface rust when long ocean transit
3. Limitation reminder (very important to inform buyers):
- It is short‑term protective coating, NOT long‑term anti‑corrosion layer
- Not suitable for direct long‑time outdoor buried / exposed service
- Varnish layer can be easily removed before hot‑dip galvanizing, final painting or other secondary anti‑corrosion treatment
- Inner surface: No varnish coating, clean black mill oxide finish
Pipe‑end options
Support Plain End (PE) flat cut (most common), Beveled End (BE) for welding, Threaded end / Grooved end for fire‑fighting pipeline
Main Application Fields
- Low‑pressure fluid transmission: Water, compressed air, ordinary steam, non‑corrosive gas
- Fire‑sprinkler pipeline system
- Construction steel structure, guardrail, fence, greenhouse frame
- Scaffolding, piling support, mechanical processing parts
- Note: Not recommended for high‑temperature & high‑pressure service; choose seamless ASTM A53 Type‑S or ASTM A106‑B for heavy‑duty high‑pressure projects
Advantage of Brisk Steel ASTM A53 ERW Black Varnish Pipe
- Weld seam annealing treatment, good ductility for threading, grooving, on‑site bending
- Uniform black varnish coating, good sea‑voyage rust‑proof performance
- Stable dimension tolerance, straight pipe body
- Fast production & delivery, competitive price compared with seamless pipe
- Flexible customization on length, pipe‑end processing, marking requirement
Frequently Asked Questions (FAQ)
Q: What is difference between black bare pipe and black varnish pipe?
A: Black bare pipe is without any paint, only hot‑rolled oxide surface, easy to get rust during long sea shipment. Black varnish pipe is sprayed thin black anti‑rust paint, for temporary rust protection on ocean transit.
Q: Can use black varnish pipe directly for outdoor project?
A: Not recommended. Black varnish coating is temporary protection. If pipes will be exposed outdoors long‑term, hot‑dip galvanized or heavy anti‑corrosion paint coating is required after you receive goods.
Q: What is difference between ERW(Type‑E) and seamless(Type‑S) under ASTM A53?
A: ERW pipe has weld seam, cost‑effective choice for low‑medium pressure fluid & structural usage. Seamless pipe has no weld seam, suitable for higher‑pressure working conditions.
Q: Can we remove the black varnish before hot‑dip galvanizing?
A: Yes, the varnish layer can be cleaned off easily before galvanizing treatment, no bad influence on galvanizing quality.
Hot Tags: astm a53 erw black varnish steel pipe, China astm a53 erw black varnish steel pipe manufacturers, suppliers, factory
