Schedule 160 (SCH 160) seamless carbon steel pipe

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Seamless carbon steel pipe with schedule 160 wall for high-pressure lines: industrial hydraulics, high-pressure steam and injection service. 6 m lengths, 12 diameters from NPS 1/2″ to 8″, dimensions per ASME B36.10-2022; usual supply is triple-certified API 5L / ASTM A106 Gr B / ASTM A53 Gr B, made to order.

VT-tubo-acero-carbon-sch160 · seamless carbon steel pipe, schedule 160 wall · 6 m lengths · made to order — quoted per project (Jul 2026)

1. TECHNICAL SPECIFICATIONS

Dimensions and calculated working pressure per diameter

NPS	DN	Outside Ø		SCH 160 wall		Weight per linear metre		Allowable pressure at ≤38 °C¹
		mm	in	mm	in	kg/m	lb/ft	bar	psi
1/2″	15	21.3	0.840	4.78	0.188	1.95	1.31	541	7,854
3/4″	20	26.7	1.050	5.56	0.219	2.90	1.95	502	7,288
1″	25	33.4	1.315	6.35	0.250	4.24	2.85	458	6,654
1-1/4″	32	42.2	1.660	6.35	0.250	5.61	3.77	363	5,266
1-1/2″	40	48.3	1.900	7.14	0.281	7.25	4.86	356	5,174
2″	50	60.3	2.375	8.74	0.344	11.11	7.47	349	5,073
2-1/2″	65	73.0	2.875	9.53	0.375	14.92	10.02	315	4,569
3″	80	88.9	3.500	11.13	0.438	21.35	14.34	302	4,382
4″	100	114.3	4.500	13.49	0.531	33.54	22.53	284	4,130
5″	125	141.3	5.563	15.88	0.625	49.12	32.99	271	3,933
6″	150	168.3	6.625	18.26	0.719	67.57	45.39	261	3,797
8″	200	219.1	8.625	23.01	0.906	111.27	74.76	253	3,675

¹ Internal pressure value calculated in the engineering calculations section (Barlow, S = 137.9 MPa, E = 1.00, −12.5% wall tolerance), rounded down. It is not a certified rating for any lot: read the calculations and the technical notice. The schedule 160 series of ASME B36.10-2022 starts at NPS 1/2″: there is no SCH 160 designation for 1/8″–3/8″.

General specifications

Product	Seamless carbon steel pipe, schedule 160 (SCH 160) wall
Material and grade	Carbon steel. The usual supply is triple-certified API 5L / ASTM A106 Gr B / ASTM A53 Gr B; the certified grade and standard(s) of each lot appear on its mill test certificate (MTC) and are confirmed at quotation.
Manufacture	Seamless (no longitudinal weld) — quality factor E = 1.00 per ASME B31.3-2024, Table A-1B
Ends	Plain or beveled for butt welding (ASME B16.25); confirmed at quotation. On schedule 160 wall the usual joint is welded; for threaded or socket-weld connections, forged fittings per ASME B16.11-2021 are used (see the high-pressure section).
Commercial length	6 m lengths
Finish	Black, no galvanic coating; the surface protection of the lot is confirmed at quotation.
Wall tolerance	Minimum wall at any point ≥ 87.5% of nominal (−12.5%), per ASTM A530 (referenced by A106) and ASTM A53
Applicable standards	ASME B36.10-2022 (dimensions) · ASTM A106/A106M-19a (seamless, high-temperature service) · ASTM A53/A53M-24 · API Spec 5L, 46th ed. (2018) · reference design code: ASME B31.3-2024

2. ENGINEERING CALCULATIONS

The allowable internal pressure is estimated with the Barlow formula, applying the manufacturing wall tolerance. Every value used is declared below — nothing is silently assumed:

P = 2 · S · E · t_ef / D

S — basic allowable stress	S = 137.9 MPa (20.0 ksi) at ≤38 °C, per ASME B31.3-2024, Table A-1, for seamless ASTM A106 Gr B and ASTM A53 Gr B (identical values for both grades, and also for API 5L Gr B). Since the three standards of the usual supply share the same S, the result does not depend on which grade the lot certifies.
E — quality factor	E = 1.00 for seamless pipe, per ASME B31.3-2024, Table A-1B (see the joint factor section).
t_ef — effective wall	t_ef = 0.875 · nominal t: the manufacturing tolerance allows the wall to be up to 12.5% below nominal at any point (ASTM A530 / A53), so the calculation uses the guaranteed minimum wall. No corrosion allowance is subtracted here (see the Design note).
D — outside diameter	Nominal outside Ø per ASME B36.10-2022 (specifications table).

Worked example — NPS 2″ (DN 50)

1. SCH 160 nominal wall: t = 8.74 mm; outside Ø: D = 60.3 mm (ASME B36.10-2022).
2. Effective wall: t_ef = 0.875 × 8.74 = 7.648 mm.
3. P = 2 × 137.9 MPa × 1.00 × 7.648 / 60.3 = 34.98 MPa ≈ 349 bar ≈ 5,073 psi.

Derived allowable pressure per diameter (≤38 °C)

NPS	Effective wall	P (MPa)	P (bar)	P (psi)
1/2″	4.183 mm	54.16	541	7,854
3/4″	4.865 mm	50.25	502	7,288
1″	5.556 mm	45.88	458	6,654
1-1/4″	5.556 mm	36.31	363	5,266
1-1/2″	6.248 mm	35.67	356	5,174
2″	7.648 mm	34.98	349	5,073
2-1/2″	8.339 mm	31.50	315	4,569
3″	9.739 mm	30.21	302	4,382
4″	11.804 mm	28.48	284	4,130
5″	13.895 mm	27.12	271	3,933
6″	15.978 mm	26.18	261	3,797
8″	20.134 mm	25.34	253	3,675

Temperature derating — S(T) per ASME B31.3-2024, Table A-1

The allowable stress S — and with it, proportionally, the allowable pressure — decreases with service temperature. Series verified for seamless A53 Gr B / A106 Gr B and API 5L Gr B (identical values for all three grades); the last column applies the factor to the NPS 2″ of this series:

Temperature		S		Factor vs. 38 °C	Allowable P, NPS 2″
°C	°F	MPa	ksi
≤38 °C	100 °F	137.9	20.0	1.000	349 bar
93 °C	200 °F	137.9	20.0	1.000	349 bar
149 °C	300 °F	137.9	20.0	1.000	349 bar
204 °C	400 °F	137.2	19.9	0.995	348 bar
260 °C	500 °F	131.0	19.0	0.950	332 bar
316 °C	600 °F	123.4	17.9	0.895	313 bar
343 °C	650 °F	119.3	17.3	0.865	302 bar
371 °C	700 °F	115.1	16.7	0.835	291 bar
399 °C	750 °F	95.8	13.9	0.695	242 bar
427 °C	800 °F	78.6	11.4	0.570	199 bar

From 371 °C onward the values are no longer yield-derived and switch to creep criteria, which is why the drop accelerates. ASME B31.3-2024, Table A-1, also warns that prolonged exposure above 427 °C may convert the steel's carbides to graphite (graphitization). For high-temperature service specify ASTM A106 Gr B, whose scope is that service; the project's design temperature and code edition govern.

3. SCH 40 VS SCH 80 VS SCH 160 — ALLOWABLE PRESSURE COMPARED

Same Barlow formula, same S = 137.9 MPa, same E = 1.00 and same −12.5% tolerance: between schedules only the ASME B36.10-2022 wall thickness t changes. The table compares the calculated allowable pressure at ≤38 °C of the three schedules at the same diameter (SCH 40 per data sheet FT-TC-TUB-SCH40-001; pressures in bar, rounded down):

NPS	t SCH 40	P SCH 40	t SCH 80	P SCH 80	t SCH 160	P SCH 160	SCH 160 / SCH 40
1/2″	2.77 mm	313 bar	3.73 mm	422 bar	4.78 mm	541 bar	1.73×
3/4″	2.87 mm	259 bar	3.91 mm	353 bar	5.56 mm	502 bar	1.94×
1″	3.38 mm	244 bar	4.55 mm	328 bar	6.35 mm	458 bar	1.88×
1-1/4″	3.56 mm	203 bar	4.85 mm	277 bar	6.35 mm	363 bar	1.79×
1-1/2″	3.68 mm	183 bar	5.08 mm	253 bar	7.14 mm	356 bar	1.95×
2″	3.91 mm	156 bar	5.54 mm	221 bar	8.74 mm	349 bar	2.24×
2-1/2″	5.16 mm	170 bar	7.01 mm	231 bar	9.53 mm	315 bar	1.85×
3″	5.49 mm	149 bar	7.62 mm	206 bar	11.13 mm	302 bar	2.03×
4″	6.02 mm	127 bar	8.56 mm	180 bar	13.49 mm	284 bar	2.24×
5″	6.55 mm	111 bar	9.53 mm	162 bar	15.88 mm	271 bar	2.44×
6″	7.11 mm	101 bar	10.97 mm	157 bar	18.26 mm	261 bar	2.58×
8″	8.18 mm	90 bar	12.70 mm	139 bar	23.01 mm	253 bar	2.81×

The SCH 160 advantage grows with diameter (from 1.73× at 1/2″ to 2.81× at 8″) because in the B36.10-2022 series its wall increases more than proportionally to the outside diameter: it is the schedule that sustains three-digit pressures in large diameters, where SCH 40 has already dropped to 90–127 bar. The ratio between schedules is a quotient of effective walls, so it stays the same at any temperature of the derating table.

4. JOINT QUALITY FACTOR E — SEAMLESS VS WELDED

The quality factor E of ASME B31.3-2024, Table A-1B, penalizes the allowable pressure according to how the pipe was manufactured — a figure almost no Spanish-language data sheet publishes, and the reason the same diameter and schedule "welded" admits less pressure:

• Seamless: E = 1.00 — the case of this product.
• Electric resistance welded (ERW): E = 0.85.
• Furnace butt welded: E = 0.60.

Effect in figures, NPS 2″ SCH 160 at ≤38 °C: seamless P = 349 bar; the same pipe in ERW version would drop to P = 349 × 0.85 ≈ 297 bar (4,312 psi). In heavy wall for high pressure, seamless also avoids the longitudinal weld as an additional inspection point. The lot's E depends on the standard and method certified on the MTC.

5. HIGH-PRESSURE SERVICE — WHEN SCH 160 IS REQUIRED

Schedule 160 is not picked from a catalog but by calculation: it is specified when the wall required by the design code —para. 304.1.2 of ASME B31.3-2024 in process piping, or the equivalent calculation of ASME B31.1-2024 in power piping— exceeds that of SCH 80. With this sheet's calculations, the calculated capacity of the series runs from 253 bar (8″) to 541 bar (1/2″) at ≤38 °C, and at NPS 2″ it keeps 291 bar at 371 °C and 199 bar at 427 °C: the range where high-pressure industrial hydraulic lines, high-pressure steam in power generation (ASME B31.1-2024 code, where the temperature derating of the calculations section governs) and high-pressure injection and process lines under ASME B31.3-2024 operate.

Matching fittings: class–schedule correlation of ASME B16.11-2021

Forged fittings (threaded and socket-weld) are classified by class, and ASME B16.11-2021 defines which pipe schedule each class corresponds to for rating purposes:

B16.11 class	Threaded end (THD)	Socket-weld end (SW)
2000	SCH 80 / XS	—
3000	SCH 160	SCH 80 / XS
6000	XXS	SCH 160
9000	—	XXS

For SCH 160 pipe: threaded Class 3000 or socket-weld Class 6000 fitting. In butt-welded joints, the fitting (elbow, tee, reducer) is specified in the same schedule 160 as the pipe to keep the wall of the whole line.

6. PIPE MARKING (STENCIL)

The pipe stencil allows verifying at receiving that what was delivered matches what was certified, by cross-checking it against the lot's mill test certificate (MTC). The marking sections of ASTM A106, ASTM A53 and API 5L require marking on each length:

• Manufacturer: name or registered brand.
• Standard(s) and grade: in triple-certified supply the stencil lists the three designations (e.g. API 5L B / A106 B / A53 B) — the lot complies with all three simultaneously.
• Size and schedule: NPS and SCH 160, or the wall thickness.
• Manufacturing method: SMLS or S = seamless.
• Heat number: the traceability key against the MTC.
• Test: hydrostatic test pressure or nondestructive examination mark, per whichever standard the lot certifies.

If the stencil does not match the MTC —grade, heat, schedule—, the length is rejected at receiving. TECTUL provides the lot's MTC upon request.

7. Application notes

8. Technical notice and limitation of liability