Hot Expanded Seamless Steel Pipe

Hot Expanded Seamless Steel Pipe–Large Diameter & High-Efficiency Solutions

Our Hot Expanded Seamless Steel Pipes provide a cost-effective alternative for projects requiring large-diameter piping without the high cost of traditional large-billet seamless manufacturing. By utilizing a specialized thermal-mechanical expansion process, we transform standard seamless mother pipes into larger diameters while maintaining structural integrity and meeting strict international engineering standards.

Common Standards and Steel Grades

We supply hot expanded pipes across a wide range of carbon and alloy grades to ensure compatibility with your project's specific pressure and temperature requirements:

ASTM A106 / ASME SA106: Grades B and C for high-temperature service.

ASTM A53: Grades A and B for general mechanical and pressure applications.

API 5L: Pipeline steel for oil and gas (Grades B, X42, X46, X52, X56, X60).

ASTM A335: Alloy steel grades for high-temp power generation (P11, P22, P91).

EN 10210 / EN 10219: Hot finished structural hollow sections (S235JR, S355JR).

Dimensional Range & Specifications

The hot expansion process is the ideal choice for large-bore piping where standard seamless production is limited:

Feature	Specification Range
Outer Diameter (OD)	10” to 48” (273.1mm – 1219mm)
Wall Thickness (WT)	SCH 20, SCH 40, SCH 80, SCH STD (up to 40mm)
Length	Single Random (5.8m), Double Random (11.8m), or Custom Cut
Tolerance	Strictly per ASTM A530 or API 5L (OD ±1%, WT ±12.5%)
End Finish	Beveled Ends (30°±5°), Plain Ends, or Special Threading

Core Application Fields

Hot expanded pipes are widely utilized in heavy-duty infrastructure and energy sectors where large-volume fluid transport is required:

Oil & Gas Midstream: Large-diameter transmission pipelines for crude oil and natural gas.

Structural Engineering: Bridge piling, offshore platform legs, and stadium frameworks.

Water Conservancy: Main water supply lines and high-pressure drainage systems.

Thermal Power Plants: Low-pressure steam lines and cooling water circulation.

Petrochemical Industry: Large-scale refinery piping and storage tank connections.

Technical Parameters of Hot Expanded Seamless Steel Pipe

Nominal size		Outside	Nominal Wall Thickness (mm)
		Diameter
DN	NPS	OD(MM)	SCH	SCH	SCH	STD	SCH	SCH	XS	SCH	SCH	SCH	SCH	SCH	XXS
			10	20	30		40	60		80	100	120	140	160
200 250 300	8 10 12	219.1 273.1 323.9	3.76 4.19 4.57	6.35 6.35 6.35	7.04  7.80 8.38	8.18 9.27 9.53	8.18 9.27 10.31	10.31 12.70 14.27	12.70 12.70 12.70	12.70 15.09 17.48	15.09 18.26 21.44	18.26 21.44 25.40	20.62 25.40 28.58	23.01 28.58 33.32	22.23 25.40 25.40
350 400 450	14 16 18	355.6 406.4 457.2	6.35 6.35 6.35	7.92 7.92 7.92	9.53 9.53 11.13	9.53 9.53 9.53	11.13 12.70 14.27	15.09 16.66 19.05	12.70 12.70 12.70	19.05 21.44 23.83	23.83 26.19 29.36	27.79 30.96 34.93	31.75 36.53 39.67	35.71 40.49 45.24	— —
500 550 600	20 22 24	508 559 610	6.35 6.35 6.35	9.53 9.53 9.53	12.70 12.70 14.27	9.53 9.53 9.53	15.09 — 17.48	20.62 22.23 24.61	12.70 12.70 12.70	26.19 28.58 30.96	32.54 34.93 38.89	38.10 41.28 46.02	44.45 47.63 52.37	50.01 53.98 59.54	— —
500 550 600	20 22 24	508 559 610	6.35 6.35 6.35	9.53 9.53 9.53	12.70 12.70 14.27	9.53 9.53 9.53	15.09 —  17.48	20.62 22.23 24.61	12.70 12.70 12.70	26.19 28.58 30.96	32.54 34.93 38.89	38.10 41.28 46.02	44.45 47.63 52.37	50.01 53.98 59.54	— —
660 700 750	26 28 30	660 711 762	7.92 7.92 7.92	12.70 12.70 12.70	— 15.88 15.88	9.53 9.53 9.53	— — —	— —	12.70 12.70 12.70	— —	— —	— —	— —	— —	— —
800 850 900	32 34 36	813 864 914	7.92 7.92 7.92	12.70 12.70 12.70	15.88 15.88 15.88	9.53 9.53 9.53	17.48 17.48 19.05	— —	12.70 12.70 12.70	— —	— —	— —	— —	— —	— —

Hot Expanded Seamless Pipe Production Process

Frequently Asked Questions

1. When do buyers usually consider hot expanded seamless pipe instead of a welded large-diameter option?

They usually consider it when they want a larger diameter but still prefer a seamless route for approval, service, or design reasons. The choice often comes from project confidence rather than from basic size availability. Typical long-tail scenarios include hot expanded seamless pipe for large diameter process piping, expanded seamless pipe for transmission lines, and large diameter seamless carbon steel pipe.

2. Why do buyers sometimes hesitate before approving hot expanded seamless pipe?

They often want reassurance on wall control, testing, and how the expanded route compares with more familiar standard seamless or welded supply. That hesitation is normal because the product sits between familiar categories. That hesitation often appears when buyers compare large diameter hot expanded seamless pipe with LSAW pipe for industrial transmission projects.

3. What kind of application tends to justify hot expanded seamless pipe most clearly?

Applications that want large diameter without giving up the seamless route are the clearest fit. Buyers usually become more confident when the product is tied to that logic rather than presented as a niche variant. The clearest fit is often in large-diameter seamless pipe demand for petrochemical, power, or long-distance process piping systems.

4. What do buyers most often need clarified before placing an order for hot expanded seamless pipe?

They usually want clarity on final dimensional control, test coverage, and whether the product will be treated in purchasing and approval the same way as standard seamless supply. Questions often center on whether hot expanded seamless pipe can satisfy the same approval logic as standard large-diameter seamless supply.