Seamless Steel Pipe
Seamless steel pipes are manufactured by hot-rolling solid round billets, producing a pipe with no weld seam and uniform wall thickness. This manufacturing process ensures superior strength, pressure resistance, and structural integrity compared to welded alternatives. Our seamless pipes comply with API 5L PSL1/PSL2 and ASTM A106 Grade B/C standards, making them suitable for the most demanding oil, gas, and petrochemical applications.
Available in sizes from DN15 to DN1200 with wall thicknesses ranging from SCH10 to SCH160, these pipes can handle pressures up to Class 2500. Each batch is traceable to its heat number and comes with full chemical composition and mechanical property test reports, including tensile strength, yield strength, elongation, and Charpy impact testing at specified temperatures.
API 5L / ASTM A106
Gr.B / X42-X70
DN15-DN1200
Applications
- High-pressure oil and gas transmission
- Boiler and heat exchanger tubing
- Structural and mechanical applications
- Chemical plant process piping
- Power plant steam lines
Quality Assurance
All Seamless Steel Pipe products undergo NDT testing with MTC per EN 10204 3.1. Third-party inspection by SGS, BV, TUV available.
Seamless Steel Pipe Technical Specifications
Seamless steel pipe is manufactured without a longitudinal weld, produced by piercing a solid billet and rolling it into a hollow tube. This produces a pipe with uniform wall thickness and superior pressure resistance compared to welded pipe.
| Parameter | Specification |
|---|---|
| Standard | API 5L / ASTM A106 / ASTM A53 / EN 10216 / DIN 1626 |
| Grade | API 5L Gr.B, X42, X46, X52, X60, X65, X70; ASTM A106 Gr.A/B/C |
| Size Range | OD 21.3mm (1/2 inch) to 1220mm (48 inch), WT 2mm-60mm |
| Manufacturing | Hot-rolled (SMLS) and Cold-drawn (CDS) processes |
| End Type | Plain End (PE), Beveled End (BE), Threaded End (TE) |
| Heat Treatment | Normalizing, Quenching and Tempering (Q&T) for high grades |
| NDT | UT full-body testing per API 5L, eddy current, hydrotest 1.5x MYP |
Manufacturing Process
Seamless pipe is produced through several methods depending on size and grade:
- Continuous Mandrel Mill: For medium diameters (60-340mm), heated billet pierced by mandrel, rolled in continuous mandrel mill.
- Plug Mill: For larger diameters (140-406mm), pierced billet rolled over a retained plug.
- Mandrel Stretch Reducing: Hot-rolled pipe further reduced to precise dimensions and wall thickness.
- Cold Drawing: For small diameters and precision wall thickness, hot-rolled tube drawn through a die at ambient temperature.
- Heat Treatment: Normalizing at 870-950C for carbon steel, Q&T for X60+ grades to achieve high yield strength.
- NDT: 100% ultrasonic testing of full body, eddy current for surface defects, hydrostatic testing at 1.5x rated pressure.
Every pipe is marked with heat number, size, grade, and standard per API 5L or ASTM requirements. MTC 3.1 includes chemical analysis, tensile test, impact test (for low-temp grades), and flattening test results.
Applications by Industry
Seamless steel pipe is specified where high pressure, temperature extremes, or critical service demands make welded pipe unsuitable:
- Oil and Gas: Onshore and offshore pipelines for sour service (H2S) per NACE MR0175, high-pressure transmission lines (X65-X70).
- Refining: Process piping for high-temperature and high-pressure hydrocarbon service.
- Power Generation: Boiler tubes, main steam and reheat lines (ASTM A335 P91 for USC boilers), feedwater piping.
- Chemical Processing: Corrosive service requiring alloy grades (P11, P22, P5) or stainless (TP304, TP316).
- Mechanical and Structural: High-strength structural applications, hydraulic cylinders, precision shafting.