304 Stainless Steel Seamless Pipe: SS 304 / 304L / 304H Seamless Pipes to ASTM A312

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SS 304 / 304L / 304H Seamless Pipe: Grade Comparison

Mill stage: the melt shop. The grade is fixed by the chemistry of the billet, before any pipe is made.

Point	SS 304 seamless	SS 304L seamless	SS 304H seamless
UNS	S30400	S30403	S30409
Carbon	0.08% max	0.035% max	0.04 to 0.10%
Grain size rule	None	None	ASTM No. 7 or coarser
Minimum tensile / yield	515 / 205 MPa	485 / 170 MPa	515 / 205 MPa
Why buy it seamless	Pressure lines where a seam is not allowed	Small bore welded process systems that must stay corrosion resistant	Steam, boiler and heater lines designed on creep strength
Dual certification	304/304L common	304/304L	304/304H possible when carbon is 0.04 to 0.08%

SS 304/ 304L / 304H Seamless Pipe Specifications 

Item	Range
Standard	ASTM A312 / ASME SA312, TP304, TP304L, TP304H
European standard	EN 10216-5 (seamless), 1.4301 / 1.4307 / 1.4948
Size range	NPS 1/8 to 12 (10.3 to 323.8 mm OD) in stock sizes; larger hot finished sizes on request
Schedules	Sch 10S, 40S, 80S, 160, XS, XXS
Finish route	Hot finished or cold finished
Length	Single random (about 5 to 7 m), double random (about 10 to 12 m) or cut to length; 5.8 m and 11.8 m for containers
Ends	Plain, bevelled to ASME B16.25, threaded on small bore
Surface	Annealed and pickled; bright annealed on cold finished sizes on request
Certificates	EN 10204 3.1; 3.2 through an independent inspector on request

Chemical Composition of TP304, TP304L and TP304H

Element, %	TP304	TP304L	TP304H
Carbon	0.08 max	0.035 max	0.04 to 0.10
Manganese	2.00 max	2.00 max	2.00 max
Phosphorus	0.045 max	0.045 max	0.045 max
Sulphur	0.030 max	0.030 max	0.030 max
Silicon	1.00 max	1.00 max	1.00 max
Chromium	18.0 to 20.0	18.0 to 20.0	18.0 to 20.0
Nickel	8.0 to 11.0	8.0 to 13.0	8.0 to 11.0
Iron	Balance	Balance	Balance

Mechanical Properties of SS 304 / 304L / 304H Seamless Pipe

Property	TP304	TP304L	TP304H
Tensile strength, min	515 MPa (75 ksi)	485 MPa (70 ksi)	515 MPa (75 ksi)
Yield strength (0.2% offset), min	205 MPa (30 ksi)	170 MPa (25 ksi)	205 MPa (30 ksi)
Elongation in 50 mm, min	35% longitudinal, 25% transverse	Same	Same
Grain size	Not required	Not required	ASTM No. 7 or coarser
Hardness	No limit for pipe; 201 HB / 92 HRB max is the ASTM A240 plate limit, for reference only	Same	Same

Thermal and Physical Properties of SS 304 Seamless Pipe

Property	Typical value
Density	7.93 g/cm³ (0.286 lb/in³)
Melting range	1400 to 1450 °C
Elastic modulus	193 GPa
Mean thermal expansion, 0 to 100 °C	17.2 µm/m·°C
Mean thermal expansion, 0 to 538 °C	18.4 µm/m·°C
Thermal conductivity at 100 °C	16.2 W/m·K
Thermal conductivity at 500 °C	21.5 W/m·K
Specific heat, 0 to 100 °C	500 J/kg·K
Electrical resistivity	0.72 µΩ·m
Scaling in air	about 870 °C intermittent, 925 °C continuous

Equivalent Grade Names for TP304, TP304L and TP304H Seamless Pipe

Mill stage: none. Use this when a drawing names a European or Japanese grade.

Standard	304	304L	304H
UNS	S30400	S30403	S30409
EN / Werkstoff No.	1.4301 (X5CrNi18-10)	1.4307 (X2CrNi18-9); 1.4306 (X2CrNi19-11) is close with more nickel	1.4948 (X6CrNi18-10)
JIS	SUS304	SUS304L	SUS304H
BS	304S31	304S11	n/a
GOST	08Kh18N10	03Kh18N11	n/a

Buyer note: 1.4301 is 304, not 304L, and the British 304L number is 304S11.

SS 304 Seamless Pipe Sizes and Weight Chart

Sizes cover NPS 1/8 to 12 (10.3 to 323.8 mm OD) in schedules 10S to XXS for SS 304, 304L and 304H seamless pipe. OD and schedule walls per ASME B36.19M; Sch 160 and XXS per ASME B36.10M. Each cell shows wall thickness in mm and weight in kg/m at 7.93 g/cm³. 

To convert to lb/ft, multiply by 0.672.

NPS (DN)	OD (mm)	Sch 10S - Wall (mm) / Weight (kg/m)	Sch 40S - Wall (mm) / Weight (kg/m)	Sch 80S - Wall (mm) / Weight (kg/m)	Sch 160S - Wall (mm) / Weight (kg/m)	XXS - Wall (mm) / Weight (kg/m)
1/8 (6)	10.3	1.24 / 0.28	1.73 / 0.37	2.41 / 0.47	n/a	n/a
1/4 (8)	13.7	1.65 / 0.50	2.24 / 0.64	3.02 / 0.80	n/a	n/a
3/8 (10)	17.1	1.65 / 0.64	2.31 / 0.85	3.20 / 1.11	n/a	n/a
1/2 (15)	21.3	2.11 / 1.01	2.77 / 1.28	3.73 / 1.63	4.78 / 1.97	7.47 / 2.57
3/4 (20)	26.7	2.11 / 1.29	2.87 / 1.70	3.91 / 2.22	5.56 / 2.93	7.82 / 3.68
1 (25)	33.4	2.77 / 2.11	3.38 / 2.53	4.55 / 3.27	6.35 / 4.28	9.09 / 5.51
1 1/4 (32)	42.2	2.77 / 2.72	3.56 / 3.43	4.85 / 4.51	6.35 / 5.67	9.70 / 7.85
1 1/2 (40)	48.3	2.77 / 3.14	3.68 / 4.09	5.08 / 5.47	7.14 / 7.32	10.15 / 9.65
2 (50)	60.3	2.77 / 3.97	3.91 / 5.49	5.54 / 7.56	8.74 / 11.23	11.07 / 13.58
2 1/2 (65)	73.0	3.05 / 5.32	5.16 / 8.72	7.01 / 11.52	9.53 / 15.07	14.02 / 20.60
3 (80)	88.9	3.05 / 6.52	5.49 / 11.41	7.62 / 15.43	11.13 / 21.56	15.24 / 27.97
4 (100)	114.3	3.05 / 8.45	6.02 / 16.24	8.56 / 22.55	13.49 / 33.88	17.12 / 41.45
5 (125)	141.3	3.40 / 11.68	6.55 / 21.99	9.53 / 31.28	15.88 / 49.62	19.05 / 58.02
6 (150)	168.3	3.40 / 13.97	7.11 / 28.55	10.97 / 43.00	18.26 / 68.25	21.95 / 80.03
8 (200)	219.1	3.76 / 20.17	8.18 / 42.98	12.70 / 65.30	23.01 / 112.41	22.23 / 109.03
10 (250)	273.0	4.19 / 28.06	9.27 / 60.91	12.70 / 82.36	28.58 / 174.03	25.40 / 156.68
12 (300)	323.8	4.57 / 36.34	9.53 / 74.61	12.70 / 98.43	33.32 / 241.13	25.40 / 188.82

Example: NPS 2 Sch 40S (60.3 x 3.91 mm) weighs 5.49 kg/m, so a 6 m length is about 33 kg. Sch 5S is a welded pipe wall and is rarely made seamless. For other grades see the SS pipe weight chart.

Buyer note: seamless pipe wall can run above nominal within the −12.5% ASTM A312 tolerance band, so actual delivered weight is often a few percent above these figures.

Have your SS 304 seamless pipe sizes confirmed? Submit your requirements - grade, schedule, length and quantity - and we will reply with a firm price within 24 hours.

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SS 304 Seamless Pipe OD and Wall Thickness Tolerances - ASTM A312

Feature	Allowed variation (ASTM A999 / A312)
OD, NPS 1/8 to 1 1/2	+0.4 / −0.8 mm
OD, over NPS 1 1/2 to 4	±0.8 mm
OD, over NPS 4 to 8	+1.6 / −0.8 mm
OD, over NPS 8 to 18	+2.4 / −0.8 mm
Wall thickness	−12.5% of nominal at any point
Cut length	+6 mm / −0

Point	Hot finished seamless	Cold finished seamless
Usual sizes	Larger diameters and heavier walls	Small and medium bores
Wall consistency	Wider variation, within −12.5%	Closer to nominal
Surface	Pickled, slightly rougher	Smoother; bright annealed possible
Typical use	Heavy wall pressure lines	Instrument, hydraulic and process lines

Where SS 304 / 304L / 304H Seamless Pipes Are Used

Industry	Typical seamless lines
Power generation	304H steam headers and boiler piping; 304 condensate lines
Refining and petrochemical	Hot process and utility lines, heater transfer lines in 304H
Chemical	304L small bore process and instrument lines
Food, dairy and pharma	Cold finished 304L process and utility lines
Hydraulics and instrumentation	Cold finished small bore 304 and 304L
Water and wastewater	High pressure pump discharge and dosing lines

Where chlorides are present (seawater, coastal air, brine), move to 316/316L pipe. For welded pipe and grade detail, see stainless steel 304 pipes.

SS 304 / 304L / 304H Seamless Pipe Supplier in Mumbai

Metinox Overseas works from Mumbai and supplies 304, 304L and 304H seamless pipe for project and stock orders. Seamless 304L is the most requested of the three, in Sch 10S, 40S and 80S from NPS 1/2 to 6. Lead time for mill orders and stock items is confirmed at quotation.

When asking a Mumbai supplier for seamless 304L, give: grade (TP304L or dual 304/304L), SMLS, OD x wall in mm or NPS and schedule, length, quantity, ends, tests and delivery port.

SS 304H Seamless Pipe: What to Check Before You Buy

304H is held by fewer stockists than 304 or 304L, so check every lot before it ships:

1. The certificate names TP304H and shows “SMLS”.
2. Carbon sits between 0.04 and 0.10%. A heat below 0.04% is 304, not 304H.
3. Grain size is reported, ASTM No. 7 or coarser.
4. The solution annealing temperature is stated.
5. The heat number on the certificate matches the stencil on every length.
6. Lengths are stored apart from 304 and 304L; they look identical.

SS 304 / 304L / 304H Seamless Pipe Price in India

SS 304 seamless pipe prices are not listed here because the nickel surcharge changes every month; see our SS 304 pipe price list.

Factor	Effect on seamless price
Seamless or welded	Seamless costs more per kg, most of all in small bores
Grade	304L is usually close to 304; 304H and dual certified pipe cost a little more
Hot or cold finished	Cold finished small bore costs more per kg
Size and wall	Very small bores and heavy walls cost more per kg
Testing	Grain size, IGC, UT and third party inspection add cost
Delivery terms	FOB, CIF and DAP differ by freight and insurance.

To convert a per kg price to price per metre, multiply by the kg/m figure from the size and weight chart above.

SS 304 Seamless Pipe Exporter in India: Packing and Dispatch

• Plastic end caps on plain ends, bevel protectors on bevelled ends
• Hexagonal bundles with non metallic straps, or wooden crates for small bore and bright annealed pipe
• Kept off carbon steel slings and racks
• Labels with grade, SMLS, size, heat number and order number on each bundle
• Lengths of 5.8 m or 11.8 m to fit 20 ft and 40 ft containers
• Sea worthy wrapping for export markets.

SS 304 / 304L / 304H Seamless Pipe FAQs