Tubewell Steel & Engg. Co. is a leading manufacturer and stockist specializing in Alloy Steel Pipes, Tubes, Fittings and Flanges for critical industrial applications.
Hot-finished and cold-drawn ASTM A335 seamless chrome-moly pipes in grades P5 to P92 – no weld seam, uniform strength for critical high-temperature service.
Tubewell Steel & Engg. Co. stocks and supplies alloy steel seamless pipes to ASTM A335 / ASME SA335 in every major P grade. Made without a longitudinal weld, seamless pipes offer uniform wall properties and full pressure rating around the circumference – the preferred choice for boilers, steam lines and refinery service where reliability is non-negotiable.
Weld-free chrome-moly pipes for high-pressure, high-temperature duty
Alloy steel seamless pipes are produced from solid round billets that are heated, pierced and rolled over a mandrel to form a hollow shell, then sized by hot finishing or further reduced by cold drawing or pilgering. Because there is no weld seam, the pipe has a homogeneous microstructure and identical mechanical properties around its full circumference, with no weld-joint efficiency factor in design. ASTM A335 covers these seamless ferritic alloy steel pipes for high-temperature service, from the economical 1Cr-½Mo P12 up to the tungsten-strengthened 9Cr P92.
Hot-finished pipes are available from 1/2" to 24" NB in schedules up to XXS, while cold-drawn pipes offer closer dimensional tolerances and a smoother surface in smaller sizes. Every pipe is heat treated to the grade requirement – annealed or normalized and tempered – and 100% non-destructively tested. We supply with EN 10204 3.1 / 3.2 certificates, IBR Form III-A and third-party inspection by BV, TÜV, SGS, Lloyd's or EIL on request.
Standard supply range for alloy steel seamless pipes
| Parameter | Details |
|---|---|
| Standard | ASTM A335, ASME SA335 |
| Grades | P5, P9, P11, P12, P22, P91, P92 |
| Manufacturing | Hot Finished (HFS), Cold Drawn (CDS), Cold Pilgered |
| Size (NB) | Hot Finished 1/2" – 24" NB; Cold Drawn 1/2" – 6" NB |
| Outer Diameter | 21.3 mm to 610 mm |
| Wall Thickness | SCH 10, 20, 40, STD, 60, 80, XS, 100, 120, 140, 160, XXS |
| Length | Single Random, Double Random, Cut Length (up to 12 m) |
| Ends | Plain End, Bevelled End (ASME B16.25), Threaded |
| Heat Treatment | Annealed or Normalized & Tempered (P91 / P92: N 1040–1080°C + T 730–800°C) |
| Surface | Black Painted, Varnished, Anti-rust Oil, Pickled |
| Dimension Standard | ASME B36.10M |
| NDT | Ultrasonic, Eddy Current or Hydrostatic per ASTM A335 / A999 |
| Mechanical Tests | Tension, Flattening, Bend, Hardness, Impact (on request) |
| Certificates | EN 10204 3.1 / 3.2, IBR Form III-A, TPI Reports |
International equivalents of ASTM A335 seamless grades
| Grade | ASTM | UNS | EN | DIN / W.Nr. | JIS | BS |
|---|---|---|---|---|---|---|
| P5 | A335 P5 | K41545 | X11CrMo5 | 1.7362 | STPA 25 | 3604 HFS 625 |
| P9 | A335 P9 | K90941 | X11CrMo9-1 | 1.7386 | STPA 26 | 3604 HFS 629-470 |
| P11 | A335 P11 | K11597 | 13CrMo4-5 | 1.7335 | STPA 23 | 3604 HFS 621 |
| P12 | A335 P12 | K11562 | 13CrMo4-5 | 1.7335 | STPA 22 | 3604 HFS 620-460 |
| P22 | A335 P22 | K21590 | 10CrMo9-10 | 1.7380 | STPA 24 | 3604 HFS 622 |
| P91 | A335 P91 | K91560 | X10CrMoVNb9-1 | 1.4903 | STPA 28 | 3604 HFS 91 |
| P92 | A335 P92 | K92460 | X10CrWMoVNb9-2 | 1.4901 | STPA 29 | — |
Weight %, as per ASTM A335
| Grade | C | Mn | P | S | Si | Cr | Mo | Others |
|---|---|---|---|---|---|---|---|---|
| P5 | 0.15 max | 0.30 – 0.60 | 0.025 max | 0.025 max | 0.50 max | 4.00 – 6.00 | 0.45 – 0.65 | — |
| P9 | 0.15 max | 0.30 – 0.60 | 0.025 max | 0.025 max | 0.25 – 1.00 | 8.00 – 10.00 | 0.90 – 1.10 | — |
| P11 | 0.05 – 0.15 | 0.30 – 0.60 | 0.025 max | 0.025 max | 0.50 – 1.00 | 1.00 – 1.50 | 0.44 – 0.65 | — |
| P12 | 0.05 – 0.15 | 0.30 – 0.61 | 0.025 max | 0.025 max | 0.50 max | 0.80 – 1.25 | 0.44 – 0.65 | — |
| P22 | 0.05 – 0.15 | 0.30 – 0.60 | 0.025 max | 0.025 max | 0.50 max | 1.90 – 2.60 | 0.87 – 1.13 | — |
| P91 | 0.08 – 0.12 | 0.30 – 0.60 | 0.020 max | 0.010 max | 0.20 – 0.50 | 8.00 – 9.50 | 0.85 – 1.05 | V 0.18–0.25, Nb 0.06–0.10, N 0.030–0.070, Ni 0.40 max, Al 0.02 max |
| P92 | 0.07 – 0.13 | 0.30 – 0.60 | 0.020 max | 0.010 max | 0.50 max | 8.50 – 9.50 | 0.30 – 0.60 | W 1.50–2.00, V 0.15–0.25, Nb 0.04–0.09, N 0.030–0.070, B 0.001–0.006, Ni 0.40 max |
Minimum values at room temperature, as per ASTM A335
| Grade | Tensile Strength | Yield Strength (0.2%) | Elongation (Long.) | Elongation (Trans.) | Hardness |
|---|---|---|---|---|---|
| P5 | 415 MPa (60 ksi) min | 205 MPa (30 ksi) min | 30% min | 20% min | — |
| P9 | 415 MPa (60 ksi) min | 205 MPa (30 ksi) min | 30% min | 20% min | — |
| P11 | 415 MPa (60 ksi) min | 205 MPa (30 ksi) min | 30% min | 20% min | — |
| P12 | 415 MPa (60 ksi) min | 220 MPa (32 ksi) min | 30% min | 20% min | — |
| P22 | 415 MPa (60 ksi) min | 205 MPa (30 ksi) min | 30% min | 20% min | — |
| P91 | 585 MPa (85 ksi) min | 415 MPa (60 ksi) min | 20% min | 13% min | 190 – 250 HBW |
| P92 | 620 MPa (90 ksi) min | 440 MPa (64 ksi) min | 20% min | 13% min | 250 HBW max |
Typical values by grade family (for reference)
| Property | P11 / P12 / P22 | P5 / P9 | P91 / P92 |
|---|---|---|---|
| Density | 7.75 – 7.85 g/cm³ | 7.70 – 7.75 g/cm³ | 7.77 – 7.85 g/cm³ |
| Melting Range | 1450 – 1510 °C | 1450 – 1500 °C | 1420 – 1500 °C |
| Modulus of Elasticity | 205 GPa | 213 GPa | 218 GPa |
| Thermal Conductivity (100°C) | 36 – 38 W/m·K | 26 – 30 W/m·K | 26 – 27 W/m·K |
| Mean Thermal Expansion (20–300°C) | 12.4 – 12.6 µm/m·°C | 11.5 µm/m·°C | 11.2 µm/m·°C |
| Specific Heat | 0.46 J/g·°C | 0.46 J/g·°C | 0.45 J/g·°C |
| Max. Service Temperature | ≈ 565 – 600 °C | ≈ 650 °C | ≈ 620 – 650 °C |
As per ASME B36.10M – wall thickness (mm) / weight (kg/m)
| NPS | OD (mm) | SCH 40 WT | SCH 40 Wt | SCH 80 WT | SCH 80 Wt | SCH 160 WT | SCH 160 Wt | XXS WT | XXS Wt |
|---|---|---|---|---|---|---|---|---|---|
| 1/2" | 21.3 | 2.77 | 1.27 | 3.73 | 1.62 | 4.78 | 1.95 | 7.47 | 2.55 |
| 3/4" | 26.7 | 2.87 | 1.69 | 3.91 | 2.20 | 5.56 | 2.90 | 7.82 | 3.64 |
| 1" | 33.4 | 3.38 | 2.50 | 4.55 | 3.24 | 6.35 | 4.24 | 9.09 | 5.45 |
| 1 1/4" | 42.2 | 3.56 | 3.39 | 4.85 | 4.47 | 6.35 | 5.61 | 9.70 | 7.77 |
| 1 1/2" | 48.3 | 3.68 | 4.05 | 5.08 | 5.41 | 7.14 | 7.25 | 10.15 | 9.56 |
| 2" | 60.3 | 3.91 | 5.44 | 5.54 | 7.48 | 8.74 | 11.11 | 11.07 | 13.44 |
| 2 1/2" | 73.0 | 5.16 | 8.63 | 7.01 | 11.41 | 9.53 | 14.92 | 14.02 | 20.39 |
| 3" | 88.9 | 5.49 | 11.29 | 7.62 | 15.27 | 11.13 | 21.35 | 15.24 | 27.68 |
| 4" | 114.3 | 6.02 | 16.07 | 8.56 | 22.32 | 13.49 | 33.54 | 17.12 | 41.03 |
| 6" | 168.3 | 7.11 | 28.26 | 10.97 | 42.56 | 18.26 | 67.56 | 21.95 | 79.22 |
| 8" | 219.1 | 8.18 | 42.55 | 12.70 | 64.64 | 23.01 | 111.27 | 22.23 | 107.92 |
| 10" | 273.1 | 9.27 | 60.29 | 15.09 | 95.98 | 28.58 | 172.33 | 25.40 | 155.15 |
| 12" | 323.9 | 10.31 | 79.71 | 17.48 | 132.05 | 33.32 | 238.76 | 25.40 | 186.97 |
| 14" | 355.6 | 11.13 | 94.55 | 19.05 | 158.10 | 35.71 | 281.70 | — | — |
| 16" | 406.4 | 12.70 | 123.30 | 21.44 | 203.53 | 40.49 | 365.35 | — | — |
| 18" | 457.0 | 14.27 | 155.80 | 23.83 | 254.55 | 45.24 | 459.37 | — | — |
| 20" | 508.0 | 15.09 | 183.42 | 26.19 | 311.17 | 50.01 | 564.81 | — | — |
| 24" | 610.0 | 17.48 | 255.41 | 30.96 | 442.08 | 59.54 | 808.22 | — | — |
WT = Wall Thickness in mm, Wt = Weight in kg/m. Values are nominal; actual weights may vary within ASTM tolerances. XXS is not defined in ASME B36.10M above 12" NB.
Where alloy steel seamless pipes are used
Main steam, reheat and feedwater lines in thermal and combined-cycle plants.
Headers, links and superheater piping under sustained heat and pressure.
Heater, hydrotreater and hydrocracker piping in sulphidic service.
Reformer, cracker and high-temperature process lines.
Gas processing and high-pressure hydrocarbon transfer piping.
Ammonia and urea plant lines resisting hydrogen attack.
Quality you can verify on every heat
Large inventory for fast dispatch
MTC EN 10204 3.1 / 3.2
Positive material identification
Pan-India & export shipping
Quick answers about alloy steel seamless pipes
Get competitive pricing, ready stock and complete documentation.
