Carbon Steel Pipe

Standards for seamless carbon steel pipes

COUNTRY	STANDARD	Name
ASTM	ASTM A179	Seamless Cold-Drawn Low-Carbon Steel Heat-Exchanger and Condenser Tubes
	ASTM A192	Seamless Carbon Steel Boiler Tubes for High-Pressure Service
	ASTM A210	Seamless Medium-Carbon Steel Boiler and Superheater Tubes
	ASTM A53	Seamless Structural Steel Tubes and Pipes, Black, Hot-Dipped, Zinc-Coated, and Galvanized
	ASTM A106	Seamless Carbon Steel Pipe for High-Temperature Service
	ASTM A334	Seamless and Welded Carbon and Alloy-Steel Tubes for Low-Temperature Service
	ASTM A519	Seamless Carbon and Alloy Steel Mechanical Tubing
API	API 5L	Line Pipes for Pipeline Transportation Systems
	API 5CT	Tubing and Casing for Wells
	API 5DP	Drill Pipes for Well Drilling
DIN	DIN17175	Heat Resitant Seamless Steel Pipelines
	DIN1629	Seamless Circular Tubes of Non Alloys Steels with Speical Quality Requirements
	DIN2391	Cold Drawn or Cold Rolled Precision Seamless Steel Tubes
EN	EN10210	Hot Finished Seamless Structural Hollow Sections of Non-Alloy Steels
	EN10216	Seamless Steel Tubes for Pressure Purposes
	EN10305	Steel Tubes for Precision Applications (Seamless Cold Drawn Tubes)
JIS	JIS G3454	Seamless Carbon Steel Pipes for Pressure Service
	JIS G3456	Seamless Carbon Steel Pipes for High Temperature Service
	JIS G3461	Seamless Carbon Steel Pipe for Boiler and Heat Exchanger
	JIS G3455	Carbon Steel Pipes for High Pressure Service

 

Classifications by Manufacturing Process

Process	Diameter Range	Wall Thickness	Typical Application
Seamless (SMLS)	NPS 1/8" - 24"	SCH 10 - SCH XXS	High-pressure, high-temp (Boilers, Gas lines)
ERW (Electric Welded)	NPS 1/2" - 24"	Up to 20mm	Low to medium pressure (Water, structural)
LSAW (Longitudinal)	NPS 16" - 60"	Up to 50mm	Long-distance oil/gas transmission
SSAW (Spiral)	NPS 8" - 100"	Up to 25.4mm	Low-pressure fluid, piling, construction

 

Carbon Steel Pipe Inspection & Testing

Inspection Item	ASTM A106 B (Seamless/High-Temp)	ASTM A53 B (SMLS or ERW/General)	API 5L PSL2 (Line Pipe/Oil & Gas)	ASTM A333 Gr.6 (Low-Temp Service)	LSAW / SSAW (Large Diameter Welded)
Manufacturing Process	Seamless (SMLS) Only	SMLS or Electric Resistance Welded (ERW)	SMLS, HFW, or Submerged Arc Welded (SAW)	Seamless or Welded	Longitudinal or Spiral Submerged Arc Welded
Chemical Analysis	Si ≥ 0.10% (Mandatory Silicon)	No Silicon requirement	Strict Carbon Equivalent (CE) limits	Fine-grain killed steel	Weld chemistry monitoring is critical
Tensile Test	415 MPa / 240 MPa (60ksi/35ksi)	415 MPa / 240 MPa (60ksi/35ksi)	Based on Grade (e.g., X52, X65)	415 MPa / 240 MPa (60ksi/35ksi)	Transverse weld tensile required
Flattening Test	Mandatory (NPS 2 & above)	Mandatory (Focus on ERW weld line)	Optional (Per agreement)	Mandatory	N/A (Guided-bend test instead)
Bending Test	Mandatory (NPS 2 & below)	Applicable	Not common	Applicable	N/A
Impact Test (CVN)	Not required	Not required	Mandatory (0°C or lower)	Mandatory (-45°C / -50°F)	Mandatory (Base metal & Weld)
Hydrostatic Test	100% Individual pipe test	100% Individual pipe test	100% Individual pipe test	100% Individual pipe test	100% Individual pipe test
NDT (Non-Destructive)	Ultrasonic (UT) or Eddy Current (ET)	Optional (Instead of Hydro)	100% UT + Weld scanning	UT / RT	100% X-Ray (RT) + Ultrasonic (UT)
Metallographic Analysis	Optional (Grain size check)	Not required	Mandatory (For PSL2)	Mandatory (Verify microstructure)	Heat Affected Zone (HAZ) inspection

 

GNEE Pipe test equipments

 

Carbon Steel Pipe Production Process

There are two main manufacturing processes for seamless carbon steel pipes, one is the cold drawing process and the other is the hot rolling process. The cold drawing process is to heat the steel billet to a certain temperature, and then use a drawing machine to draw the steel billet into a pipe; the hot rolling process is to heat the steel billet to a certain temperature, and then roll the steel billet into a pipe through a rolling mill. Both processes have their own advantages and disadvantages, and which process to choose depends on the use environment and requirements.

 

Coating Types for Carbon Steel Pipe

Temporary Mill Protection (Short-term Storage)

Designed to prevent rust during sea transit and warehouse storage.

 

Black Varnish / Anti-rust Oil:

Thickness: 15-30 μm.

Characteristics: Low cost and weldable (minimal cleaning required before welding).

Application: The "standard finish" for most ASTM A106/A53 pipes.

Clear Varnish: Allows for visual inspection of the steel surface and markings.

High-Performance External Coatings (Long-distance Pipelines)

The primary choice for buried oil and gas transmission lines.

 

3PE (Three-Layer Polyethylene):

Structure: FBE (Bottom) + Adhesive (Middle) + Polyethylene (Top).

Technical Data: Service life up to 50 years; Operating temperature up to 80°C; Thickness: 2.0mm - 3.5mm.

Advantage: Excellent resistance to mechanical damage and electrical insulation.

 

FBE (Fusion Bonded Epoxy):

Thickness: 300 - 600 μm.

Technical Data: Superior adhesion; Heat resistance up to 100°C.

Application: Often used for directional drilling or as a primer for 3PE.

 

3PP (Three-Layer Polypropylene):

Structure: Similar to 3PE but with higher heat resistance (up to 110°C - 140°C).

Application: High-temperature environments or deep-sea hot oil/gas transmission.

Metallic Coatings

 

Hot-Dip Galvanized:

Standards: ASTM A123 / ASTM A53.

Technical Data: Zinc weight ≥ 550 g/m² or thickness ≥ 85 μm.

Application: Fire protection systems, irrigation, and structural engineering. Uses "sacrificial anode" protection.

Internal Linings

Designed to improve flow efficiency or prevent internal corrosion.

 

Liquid Epoxy Lining:

Function: Reduces internal friction (drag reduction) and increases flow capacity.

Application: Natural gas pipelines (Typically 60-100 μm).

 

Cement Mortar Lining:

Application: Municipal potable water transmission. Utilizes high alkalinity to inhibit electrochemical corrosion.

 

CRA Clad / Lined (Bimetallic Pipe):

Feature: Carbon steel outer layer for pressure resistance, lined with stainless steel or nickel alloys (e.g., 316L, Inconel 625).

Application: Highly corrosive media (containing H2S or CO2).

 

Comparison Table of Coating Performance

Coating Type	Corrosion Resistance	Impact Resistance	Temp Range	Design Life
Black Varnish	Low	Low	-20°C to 100°C	< 1 year (Storage)
3PE	Extreme	Extreme	-40°C to 80°C	30 - 50 years
FBE	High	Medium	-30°C to 100°C	20 - 30 years
Galvanized	High	High	Up to 200°C	15 - 25 years
3PP	Extreme	Extreme	-20°C to 140°C	30 - 50 years

 

Application of Carbon Steel Pipe

Carbon steel pipes are widely used in many fields due to their excellent corrosion resistance, strength, pressure bearing capacity and processability. Specific application areas are as follows:
A179 carbon steel pipes can be used in water, gas and oil pipelines in buildings, as well as stairs, handrails, railings and other components. In addition, it is also used in structural projects such as bridges, high-rise buildings, roads and tunnels to support and transmit loads.
A53 carbon steel pipe is suitable for the chemical industry and is used to transport chemicals, gases and other pipelines.
A106 carbon steel pipe is an important pipeline material for transporting oil and natural gas. It has high strength, reliability and corrosion resistance.
A519 carbon steel pipes are used to manufacture exhaust pipes, body frames, chassis and other parts because of their good wear resistance and strength.
In mechanical engineering, seamless carbon steel pipes are used in conveying systems, pressure vessels, hydraulic systems and other components.

Packaging Of Carbon Steel Pipe

According to the nominal pipe size (NPS) and customer requirements, we provide the following three core packaging methods:

‌Hexagonal Bundling‌ — For medium and small diameters (NPS 1/8" - 8")
Packaging details: Multiple strapping is carried out with steel strips, and the weight of each bundle is usually controlled at 2,000kg - 3,000kg for convenient hoisting.
Hoisting reinforcement: Nylon slings can be added at the binding position, which facilitates direct unloading at the destination port and avoids damage to the pipe body caused by direct contact of steel wire ropes.
Protection: The outer layer of each bundle of pipes can be wrapped with waterproof woven bags to prevent salt spray corrosion during sea transportation.

‌Loose Packing‌ — For large diameters (NPS 10" and above)
Support: Internal bracing can be installed inside the pipe to prevent large-diameter thin-walled pipes from out-of-round deformation during stacking and transportation.
Stacking: Dunnage is laid at the bottom and between layers to prevent direct friction between metals.

‌Wooden Crate Packing for special pipes‌ — For high-precision/small wall thickness pipes
Applicable cases: Such as ASTM A179 heat exchanger tubes and cold-drawn precision pipes.
Advantages: Provides all-round mechanical protection, completely eliminating bumps and scratches.

 

End Protectors‌:

Plastic Caps: Prevent impurities and water vapor from entering the pipes.

Bevel Protectors: Designed for large-diameter beveled pipes to protect the bevel from damage during collision.

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Surface Treatment‌:

Default coating is black varnish or anti-rust oil.

For high-requirement projects, 3PE or FBE coating is available.

 

We will calculate the most economical logistics method based on the total tonnage of the order:

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Container Shipping (FCL)‌

20GP (20-foot container): Length limit is 5.8m. It is suitable for fixed-length pipes of 5.8m, with a load capacity of about 25-27 tons.

40GP/HC (40-foot container): Length limit is 11.8m. It is suitable for 6m or 12m (DRL) pipes.

Lashing: Wooden dunnage is used to fix the bottom inside the container, and steel wire ropes are used for cross reinforcement to ensure no displacement during sea navigation.

‌Break Bulk / Bulk Vessel‌

Applicability: For large-volume orders (usually >100 tons) or pipes with a length exceeding 12m.

Advantage: Freight is calculated by volume (CBM) or weight, which has a prominent cost advantage in bulk trade.

Supervision: Professional loading supervisors will be arranged to ensure that the stacking layers of pipes at the bottom of the cabin meet safety standards and avoid crushing.

Marking & Traceability

Stenciling‌: The surface of each pipe is clearly marked: GNEE PIPE - ASTM A106 Gr.B - SMLS - 8" SCH40 - HEAT NO. - LENGTH.

‌Shipping Tags‌: Each bundle of pipes is hung with a wear-resistant stainless steel or plastic tag, recording bundle number, specification, quantity, gross weight/net weight, to ensure correct counting on site during delivery.

We're well-known as one of the leading carbon steel pipe manufacturers and suppliers in China. If you're going to buy discount carbon steel pipe in stock, welcome to get quotation and free sample from our factory. Also, customized service is available.

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