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GB/T 3091 Welded Carbon Steel Pipe

GB/T 3091-2025 Welded carbon steel pipes for low-pressure fluid transportation: Nominal pressure ≤ 1.6MPa, for transporting low-pressure fluids such as water, sewage, gas, air, and heating steam. Mainstream export materials: Q195, Q215, Q235B, Q355B (new in 2025 edition).

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GB/T 3091-2025 Welded Carbon Steel Pipes for Low-Pressure Fluid Transportation Application Scope: Nominal pressure ≤ 1.6MPa, for conveying low-pressure fluids such as water, sewage, gas, air, and heating steam.

Main Export Materials: Q195, Q215, Q235B, Q355B (New in 2025 Edition)

Material Introduction

Q195: Low-carbon mild steel, excellent plasticity, toughness, and weldability; easy to cold bend/stamp.

Lowest strength, used for low-pressure, light-load, non-load-bearing fluid pipelines (general water supply and drainage, ventilation).

Q215: Slightly higher strength than Q195, balanced plasticity and weldability.

General-purpose low-pressure pipeline, high cost-performance ratio, used for civil/municipal basic fluid transportation.

Q235B (Best-Selling): Most commonly used carbon structural steel, with the best overall strength, plasticity, weldability, and corrosion resistance.

Used for building water supply and drainage, gas, municipal pipe networks, industrial low-pressure pipelines, and fire protection pipelines.

Q355B: Strength higher than Q235B. Approximately 50% higher strength, with good low-temperature toughness. Suitable for medium and low pressure heavy-duty pipelines, long-distance transportation, and projects with higher strength requirements.

Product Name		Carbon steel pipe/tube
More materials		20#, Q235B, A53B, S235JR, STPG38,A106B, P235GH, STB410,L245/L360, API 5L X42/X52/X60/X65, Gr.B, A333 Gr.1/Gr.6,Q355B, S355JR, A572Gr50
Best-selling specifications	Seamless pipe	20#, Q355B, A106B	6-630	1–18
	ERW straight seam welded pipe	Q235B, A53B	21-323	2.8–6
	Spiral welded pipe	Q235B, L245, X52	219-1220+	6–25
	Square tube	Q235B、Q355B、S235JR	20×20-200×200	1.5-10
	Rectangular tube	Q235B、Q355B、S235JR	20×40-150×300	1.5-10
Length		6/12m（Current inventory on hand and ready for use）, Length can be customized
Surface treatment		Black Pipe，Varnish / Anti-rust Paint，Anti-rust Oil / Preservative Oil，Sand Blasting / Shot Blasting，Hot Dipped Galvanized，Painting / Coating
Delivery Condition		Hot Rolled / Hot Rolled Seamless (HR), Cold Drawn / Cold Drawn (CD), Normalized / N, Annealed / A, Quenched and Tempered / Quenched and Tempered (QT)
Standard		ASTM, AISI, JIS, GB, DIN, EN, etc.
Surface		Black, Bright Polished, Rough Turning, Matt Surface Treatment, No. 4. BA, etc.
Scope of Application		Common applications for stainless steel pipes include food processing,Textile operations, Breweries, Water treatment plants, Oil and gas processing,Fertilizers and pesticides, Chemical applications,Construction, Pharmaceuticals, Auto parts, etc.
Certificate		ISO, SGS, BV, etc.
Production Technology		Hot Rolling, Cold Rolling
Edge Processing		Edging, Trimming

Product Advantages:

Mature Standards, Internationally Compliant:Complies with GB/T 3091-2025 and ASTM A53, EN 10255, and ISO 65 standards, ensuring high acceptance in global municipal, water supply, and gas markets, and smooth customs clearance.

Mature Welding Technology, Extremely Low Cost:High-frequency straight seam welding (ERW)/spiral welding offers high production efficiency and prices 30%~50% lower than seamless pipes, making it a globally leading cost-performance ratio.

Comprehensive Material Coverage, Wide Adaptability:Q195/Q215 (light load) → Q235B (general mainstream) → Q355B (high strength), meeting all low-pressure scenarios.

Zinc-plating/Anti-corrosion Processes, Long Service Life:Hot-dip galvanizing (300/500g/m²), epoxy coating, internal and external anti-corrosion, corrosion-resistant, anti-aging, suitable for underground/humid environments.

Full range of specifications, container compatible. 100% ultrasonic/eddy current flaw detection + hydrostatic test (1.5 times the design pressure) for welds. Welds are of equal strength to the base material, with no risk of leakage.

Chemical composition (mass fraction %)

Brand	C	Si	Mn	P ≤	S ≤
Q195	≤0.12	≤0.30	0.25~0.50	0.045	0.045
Q215	≤0.15	≤0.30	0.25~0.55	0.045	0.045
Q235B	≤0.20	≤0.35	0.30~0.70	0.045	0.045
Q355B	≤0.24	≤0.50	1.00~1.60	0.030	0.030

Mechanical properties

Grade	Tensile strength σb (MPa)	Upper yield strength ReH (MPa) ≥	Post-rupture elongation A ≥ (%)	Cold bending test (180°)	Impact test
Q195	315~430	195	20	d = 0 - No cracks	-
Q215	335~450	215	20	d = 0.5a - No cracks	-
Q235B	370~500	235	20	d = a - No cracks	≥27J (at room temperature)
Q355B	470~630	355	18	d = 2a - No cracks	≥34J (at room temperature)

Statistics on the popular models and common specifications of carbon steel pipes

Standard model	Common outer diameter range (mm)	Common wall thickness series	Common length
ASTM A53 Gr.B	21.3～610	SCH40、SCH80、STD	6m / 12m
ASTM A106 Gr.B	21.3～610	SCH40、SCH80、STD、XS	6m / 12m
API 5L Gr.B / X42 / X52	114～1422	SCH40, STD, XS, Customized wall thickness	6m / 12m
GB/T 8163 20#	10～630	SCH40, SCH80, Standard wall thickness	6m / 12m
EN 10216 P235TR1	17.2～610	SCH40, S235, Standard wall thickness	6m / 12m
JIS STPG370 / STPG410	15～600	SCH40, SCH80, Standard wall thickness	6m / 12m

Select materials based on application

For general fluid transportation (water, gas, oil): 20#, Q235B, A53 Gr.B, STPG370

The best cost-performance ratio, globally applicable

For high-temperature / steam / boiler pipes: A106 Gr.B, 20G, 15CrMoG, P235TR1/P235GH

Better resistance to high temperature and pressure

For oil and gas pipelines: API 5L Gr.B, X42, X52, X60

High strength and good toughness, suitable for long-distance pipelines

For low-temperature environments (cold storage, LNG support): A333 Gr.1/Gr.3, 16MnDG

Resistant to low temperature without cracking

For structural pipes (supports, machinery, steel structures): Q355B (old 16Mn), St44.2, A36

High strength and good load-bearing capacity

Our Advantages:

Professional manufacturer of carbon steel pipes with years of export experience.

Full standards: GB, ASTM, API 5L, EN, JIS available.

Complete sizes: OD 12.7–711mm, SCH40/SCH80/STD/XS.

Strict quality control with MTC, accept SGS/BV inspection.

Stable production & fast delivery.

Competitive price for bulk orders.

Export Packaging:

Steel strips bundling + plastic pipe caps.

Anti-rust oil + woven bag for sea transportation.

Wooden pallet & container reinforcement available.

Standard shipping marks for custom clearance.

Payment Methods

Flexible payment terms available: T/T and L/C. For new clients, 30% advance payment for production, balance against copy of B/L. L/C is acceptable for large & regular orders to secure both parties.

Previous:GB/T 5310 Boiler Pressure Pipe

Next:GB/T 9711 Industrial Spiral Welded Pipe

Warehousing Management

Before each batch of steel leaves the factory, a complete process inspection is strictly carried out. From chemical composition, mechanical properties to dimensional tolerance and surface quality, each item is carefully checked to ensure compliance with national standards and export regulations. At the same time, the quantity, packaging and rust prevention treatment are also verified. An original factory warranty certificate is attached, guaranteeing the quality. Before shipment, inspection photos are provided. Any non-compliant items will not be released, and the quality is fully controllable throughout the process. This ensures your overseas purchasing is safe and worry-free.

All items are visually inspected before delivery. No cracks, deformation, rust, scratches or cutting marks are allowed; edges must be smooth. Only visually sound products will be shipped.

Thickness, width, length, wall thickness, outer diameter have been measured. Straightness, curvature, torsion, diagonal tolerance all meet the corresponding tolerance requirements.

Quality inspection includes: mechanical property tests (yield strength, tensile strength), elongation rate, impact energy, hardness testing, chemical composition testing, process performance testing, etc.

Inspection according to packaging requirements: secure binding, moisture-proof film, rust-proof paper, export fumigation/fumigation-free wooden crates, shipping marks, gross weight, net weight, etc.

We will provide full reception services to support the customers' on-site inspection of the goods.

Hot Rolling Production Line

Cold rolling precision processing

Cold drawing/cold rolling line

Hot Rolling Production Line

Hot rolling production line (producing hot-rolled coils/medium-thick plates, thickness 2–60mm)

Cold rolling precision processing

(Producing ultra-thin / high-precision / shiny panels, with thickness ranging from 0.1 to 3mm, for high-end products)
Cold drawing/cold rolling line

(High-precision cold-drawn round steel, square steel, hexagonal steel, and special-shaped bars)

Cold drawing/cold rolling line

(High-precision cold-drawn round steel, square steel, hexagonal steel, and special-shaped bars)

Warehousing Management

A ten-thousand-ton standardized warehouse with grid-based zoning and system positioning enables rapid material retrieval and reduces the time spent searching for materials.

Inbound inspection: Verify the physical items against the inbound form, inspect the appearance, dimensions, and labels. Once confirmed to be correct, the materials are entered into the ERP system and processed for storage.

Logistics and Global Delivery: Self-operated fleet + contracted logistics partners; expedited service available for urgent orders.

International Shipping: Supports FOB, CIF, DDP, and other trade terms, covering 100+ countries and regions.

Process: Booking → Trucking → Customs Declaration → Loading onto Ship/Aircraft → Bill of Lading Issuance → Document Delivery → Destination Port Customs Clearance (Optional) → Last-Mile Delivery.

Provides door-to-door one-stop logistics with full tracking to ensure safe and timely arrival of goods.

After-Sales Service and Traceability: Delivery receipts, logistics information, and quality inspection documents are sent to customers within 24 hours of shipment.

Established a full product lifecycle traceability system, allowing tracking of production, quality inspection, warehousing, and transportation records.

Follow-up inspection within 72 hours of arrival; rapid response and handling of quality issues; assistance in resolving customs clearance issues for foreign trade orders.

Packaging Method