About Us
Eastern Steel Manufacturing Co.,Ltd is a leading manufacturer and distributor of seamless steel pipe, welded steel pipe, OCTG products and fittings. We supply first-step processing, semi-finished parts and finished parts to help our clients meet fabrication requirements beyond their capacity or to improve operations by moving forward the pre-production processing.
News
In this column you can find the steel pipe related articles you need, including industry trends, product standards and materials, and some technical guidelines.
Services
Eastern Steel Manufacturing Co.,Ltd not only improve product production and sales services, but also provide additional value-added services. As long as you need, we can complete your specific needs together.
Facility
Eastern Steel Manufacturing Co.,Ltd not only improve product production and sales services, but also provide additional value-added services. As long as you need, we can complete your specific needs together.
Projects
Many years of large-scale project experience in various fields（Oil & Gas, Construction, Power Energy, Marine & Offshore, Water Treatment, Exploration & Drilling Services, Pipeline & Petrochemical etc.）, professional project team is responsible from receiving until the end of the project.
Black steel and carbon steel identify different aspects of a steel pipe. Carbon steel identifies the material and its grade, while black steel generally indicates an uncoated or ungalvanized surface condition.
A black steel pipe can be made from carbon steel, but "black" does not define a separate steel grade or a fixed carbon content.
Black Steel Pipe vs. Carbon Steel Pipe — Comparison
| Feature | Black Steel Pipe | Carbon Steel Pipe |
|---|---|---|
| Material | Often carbon steel | Carbon steel |
| Surface condition | Generally black, uncoated or ungalvanized | May be bare, galvanized or coated |
| Typical standards | ASTM A53, ASTM A106, API 5L and other applicable standards | ASTM A53, ASTM A106, API 5L, EN and other applicable standards |
| What the term defines | Surface condition | Material and grade |
The dark surface commonly comes from iron-oxide mill scale formed during high-temperature processing such as hot rolling or hot forming.
Different carbon steel grades have different limits for carbon and other alloying elements.
For example, carbon steel pipe may be supplied to grades such as ASTM A53 Grade B, ASTM A106 Grade B and API 5L X52. These grades have their own requirements for chemical composition and mechanical properties.
Common Steel Grades — Mechanical Strength Reference
| Material Grade | Minimum Yield Strength | Minimum Tensile Strength | Typical Use |
|---|---|---|---|
| ASTM A53 Grade B | 240 MPa (35 ksi) | 415 MPa (60 ksi) | General service and structural applications |
| ASTM A106 Grade B | 240 MPa (35 ksi) | 415 MPa (60 ksi) | High-temperature seamless piping |
| API 5L X52 | 360 MPa (52 ksi) | 460 MPa (66 ksi) | Oil and gas line pipe |
The supplied pipe’s chemical composition and mechanical test results are recorded in the Mill Test Certificate (MTR) against the applicable standard.
Both carbon steel and black steel pipe can be supplied as welded or seamless pipe.
Welded pipe: ERW (Electric Resistance Welded), LSAW (Longitudinal Submerged Arc Welded), or SSAW (Spiral Submerged Arc Welded).
Seamless pipe: Produced from solid billet by hot rolling, hot extrusion or cold drawing, without a weld seam.
Carbon steel is inherently prone to atmospheric and chemical oxidation. The natural dark iron-oxide scale on black pipe provides short-term transit protection only. Where long-term corrosion resistance is required, surface treatments (e.g., Hot-Dip Galvanizing, 3LPE, or FBE) must be ordered as a separate line-item specification.
Q1. Is black steel pipe the same as carbon steel pipe?
Not necessarily. Carbon steel identifies the material and grade, while black steel generally describes the surface condition. A carbon steel pipe can therefore also be supplied as a black steel pipe.
Q2. Does black steel pipe have a fixed carbon content or pressure rating?
No. “Black steel” does not specify a particular carbon content, yield strength or pressure rating. These requirements come from the specified grade and applicable standard, such as ASTM A106 or API 5L.
Q3. Can a seamless carbon steel pipe be delivered as a black pipe?
Yes. Seamless carbon steel pipe can be supplied with a black mill-scale surface. The terms “seamless,” “carbon steel” and “black” describe different aspects of the pipe and can appear together in the same specification.
ERW vs. Seamless Black Steel Pipe
E-mail: sales@eastern-steels.com
