UNS S30400|1.4301|TP304 Seamless Stainless Steel Tube

TP304 Stainless Steel Seamless Tubes are the industry standard for high-performance, corrosion-resistant piping solutions. Engineered from premium 18-8 chromium-nickel austenitic alloy, these tubes provide an optimal balance of mechanical strength, superior formability, and long-term reliability in mildly corrosive environments.
As a dedicated stainless steel seamless tube manufacturer based in Wenzhou’s industrial hub, Xinzhe specializes in high-precision Cold Drawn (CD) and Cold Rolled production processes. Our facility integrates advanced heat treatment and precision finishing to ensure every tube features a homogeneous metallurgical structure and exceptional dimensional stability.
Compared to welded alternatives, our seamless TP304 tubes offer enhanced structural integrity, making them the preferred choice for high-pressure systems and critical fluid transport.

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What Is a Seamless Stainless Steel TP304 Tube?

Seamless TP304 (UNS S30400 / W.Nr. 1.4301) tube is the industry-standard austenitic stainless steel for corrosion-resistant tubing. Its balanced 18% chromium and 8% nickel chemistry gives a stable austenitic structure with good resistance to oxidising media, excellent toughness from cryogenic to moderately elevated temperatures, and outstanding fabrication characteristics.

A Seamless Stainless Steel TP304 Tube is a high-performance, pressure-rated cylindrical component produced through an extrusion and cold-finishing process. Unlike welded alternatives, these tubes are engineered from a solid stainless steel billet, ensuring a seamless, continuous metal structure that eliminates the risk of longitudinal failure.

As the industry-standard"18/8"austenitic grade, Type 304 is the most versatile alloy for tubing. It offers a strategic balance of high ductility, excellent oxidation resistance, and long-term cost-efficiency in diverse industrial environments.

Key Features and Technical Advantages

While standard piping focuses on fluid volume, TP304 seamless tubing is defined by its rigorous dimensional control and structural integrity:

Tight Dimensional Tolerances

Through precision cold-drawing (CD) or cold-rolling, these tubes achieve superior accuracy in Outside Diameter (OD) and Wall Thickness (WT), essential for high-tolerance fittings.

Enhanced Surface Integrity

The manufacturing process results in a superior surface finish (often reaching Ra ≤ 0.8μm or better), minimizing turbulence in fluid flow and preventing bio-fouling in sensitive applications.

Superior Pressure Rating

The absence of a weld seam allows for higher working pressures and safety factors, making them indispensable for critical hydraulic and instrumentation systems.

Excellent Formability

The inherent ductility of the 304 grade allows for complex fabrication, including coiling, 180° bending, and flaring, without compromising the material's microstructural stability.

Product Specifications and Data

To provide a comprehensive overview of this high-performance material, here are the detailed technical specifications and performance data for 304L stainless steel.

C	Si	Mn	P	S	Cr	Ni	Fe
≤ 0.08	≤ 0.75	≤ 2.0	≤ 0.045	≤ 0.03	18.0 - 20.0	8.0 - 11.0	Balance

Dimensional Standards and Tolerances

TP304 seamless tubes are produced to the dimensional tolerances of ASTM A213 / A213M, ASTM A269 or ASTM A312, with inspection criteria taken from ASTM A1016 / A1016M.

Table 4: The Standard of Stainless Steel Seamless Tube Size Tolerance Size Chart :

Standard	OD(D)	Tolerance（MM)		Thickness(S)	Tolerance(MM)	Length	Tolerance
	MM	Common	High	MM			MM
EN 10216-5 HFD	30≤D≤219.1（D2)	±1.0% or ±0.5mm, whicever is the greater(取较大者)		T1, T≤4	±15% or ±0.6mm, whicever is the greater(取较大者)	L≤6M	+5/0
				T2	±12.5% or ±0.4mm, whicever is the greater(取较大者)
	219.1≤D≤610 (D1)	±1.5% or ±0.75mm, whicever is the greater (取较大者)		T≤0.05D	+22.5%/-15%	6≤12	+10/0
				T1, 0.05D≤0.09D	±15% or ±0.6mm, whicever is the greater(取较大者)
				T2, T>0.09D	±12.5% or ±0.4mm, whicever is the greater(取较大者)	L>12	+by agreement/0
EN 10216-5 CFD	D3(D≤219.1)	±0.75% or ±0.3mm, whicever is the greater(取较大者)		T3	±10% or ±0.2mm, whicever is the greater(取较大者)
	D4(D≤219.1)	±0.5% or ±0.mm, whicever is the greater(取较大者)		T4	±7.5% or ±0.15mm, whicever is the greater(取较大者)
ASTM A213 HFD	D≤100	+0.4/-0.8		D<100,S≤2.4	+40%/0	HFD, all size	+5.0/0
		+0.4/-1.2		D<100,2.4≤3.8	+35%/0
		+0.4/-1.6		D<100,3.8≤4.6	+33%/0
				D<100,S>4.6	+28%/0
	100≤200	+0.4/-1.2		D>100, 2.4≤3.8	+35%/0
	200≤225	+0.4/-1.6		D>100,3.8≤4.6	+33%/0
				D>100,S>4.6	+28%/0
ASTM A213 CFD	D<25	±0.10		D≤38.1	+20%/0	CFD, D<50.8	+3.0/0
	25≤D≤40	±0.15
	40	±0.20
	50≤D<65	±0.25
	65≤D<75	±0.30		D>38.1	+22%/0	CFD, D≥50.8	+5.0/0
	75≤D≤100	±0.38
	100≤200	+0.38/-0.64
	200≤225	+0.38/-1.14
ASTM A269	D≤13	±0.13		D≤13	±15%	D<38	+3.2/0
	13	±0.13		13	±10%
	38≤D<89	±0.25				D>38	+4.8/0
	89≤D<140	±0.38
	140≤D<203	±0.76
	203≤D<305	±1.01
	305≤D<356	±1.26
ASTM A270	D<25	±0.13		For weld pipe all size	±12.5%		+3.0/0
	25-50	±0.20
	50-75	±0.25
	75-100	±0.38		For CD SMLS pipe D≤38.1	+20%/0
	100-140	±0.38					+5.0/0
	140-200	±0.75		For CD SMLS pipe D>38.1	+22%/0
	200-300	±1.25

Common Industrial Applications

Food and Beverage

Hygienic product and utility tubing
Dairy, brewery and bottling lines
Clean-in-place circuit pipework

Water Treatment and Desalination

Potable and process water tubing
Multi-stage flash and RO support pipework
Filtration and dosing lines

General Chemical and Process

Oxidising and mildly reducing media
Heat exchanger and condenser tubing
Process and utility pipework

Architectural, Automotive and Instrumentation

Decorative and structural tubular components
Exhaust and fuel system tubing
Precision instrument and sensor housings

Quality Assurance and Manufacturing Process

Certification and Documentation

All TP304 tubes are supplied to ASTM A213 / A269 / A312 with EN 10204 3.1 mill test certificates. Third-party inspection and full heat-number traceability are available on request.

Non-Destructive Testing (NDT)

Hydrostatic or eddy-current testing is performed on 100% of tubes, with ultrasonic testing and dye-penetrant inspection available for critical service applications.

Mechanical and Metallurgical Testing

Tensile, yield, elongation and hardness tests are carried out per heat. Grain size, microstructure and intergranular corrosion testing per ASTM A262 are available where specified.

Dimensional and Surface Inspection

Outside diameter, wall thickness, ovality and straightness are verified against ASTM A1016 / A1016M, with surface finish inspected for both industrial and hygienic service.

TP304 vs TP316 – Technical Comparison

TP304 and TP316 are the two workhorses of austenitic stainless tubing. They are metallurgically related, but the molybdenum addition in TP316 shifts the corrosion envelope decisively in chloride and reducing-acid service.

Chemical Composition

Molybdenum: TP316 2.00–3.00 % vs none in TP304
Nickel: TP316 10.0–14.0 % vs TP304 8.0–10.5 %
Chromium: both 16.0–18.0 % (TP316) / 18.0–20.0 % (TP304)
Carbon: both ≤ 0.080 %

Corrosion Performance

PREN: TP316 ≈ 24–26 vs TP304 ≈ 18–19
TP316 resists pitting and crevice attack in chlorides and seawater far better than TP304
TP316 tolerates reducing acids such as sulphuric and phosphoric acid where TP304 performs poorly
TP304 is fully adequate in oxidising media, fresh water and atmospheric service

Mechanical and Thermal Properties

Tensile strength: both ≥ 515 MPa
Yield strength (0.2 %): both ≥ 205 MPa
TP304 shows slightly better thermal conductivity and lower cost
Both remain fully austenitic and non-magnetic in the annealed condition

Selection Guidance

Choose TP304 for general-purpose, mildly corrosive and food-grade service where cost matters
Choose TP316 for chlorides, seawater, reducing acids, pulp and paper, and pharmaceutical duty
For welded heavy sections in TP316 duty, prefer TP316L to avoid post-weld sensitisation

Frequently Asked Questions

What is TP304 stainless steel tube?

TP304 is the standard 18 % chromium / 8 % nickel austenitic stainless steel in seamless tube form, covered by UNS S30400 and W.Nr. 1.4301. It offers good resistance to oxidising media, excellent toughness from cryogenic to moderately elevated temperatures, and outstanding formability and weldability.

Which standards cover TP304 seamless tubes?

TP304 seamless tubing is typically supplied to ASTM A213 / A213M, ASTM A269 or ASTM A312, with dimensional inspection per ASTM A1016 / A1016M. Equivalent specifications include EN 10216-5 grade 1.4301 and JIS G3459 SUS304.

What is the difference between TP304 and TP316?

TP316 contains 2.00–3.00 % molybdenum while TP304 contains none. That addition raises the pitting resistance equivalent number from roughly 18–19 to 24–26, giving TP316 markedly better resistance to chloride pitting, crevice attack and reducing acids. TP304 remains the more economical choice for mildly corrosive and oxidising service.

Can TP304 tubes be used in food and pharmaceutical service?

Yes. TP304 is widely used for hygienic tubing in dairy, brewery, beverage and general food contact duty. Where chlorides, aggressive cleaning chemicals or higher-purity requirements apply, TP316L is normally preferred. Surface finish and roughness can be specified and verified for hygienic applications.