TP304L Stainless Steel Seamless Pipe

UNS S30403|1.4307|TP304L Seamless Stainless Steel Pipe

UNS S30403|1.4307|TP304L Seamless Stainless Steel Pipe
Seamless Stainless Steel TP304L Pipes (UNS S30403) are premium low-carbon austenitic solutions engineered to eliminate carbide precipitation during welding. As a specialized manufacturer in Wenzhou, China, XinZhe produces high-integrity 304L seamless piping that strictly complies with ASTM A312, ASME SA312, and EN 10216-5 standards.

Due to its reduced carbon content, our TP304L tubing offers superior intergranular corrosion resistance, making it the ideal choice for heavy-gauge welded components in chemical processing, cryogenic applications, and pharmaceutical systems. Through advanced cold-drawing and bright annealing processes, XinZhe ensures every pipe maintains precise dimensional tolerances and a high-quality surface finish. Rely on our expertise for certified stainless steel solutions that guarantee long-term structural integrity in corrosive environments.
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What Is a Seamless Stainless steel TP304L Pipe?

Seamless Stainless Steel TP304L Pipe – Low-Carbon Austenitic Stainless Steel for Welded and Corrosion-Resistant Systems

ASeamless Stainless Steel TP304L Pipe is a corrosion-resistant industrial pipe manufactured from a solid stainless steel billetthroughhot extrusion or cold drawing processes. The seamless manufacturing method eliminates longitudinal weld seams, ensuring uniform metallurgical structure, improved pressure resistance, and consistent mechanical properties.

Key Features and Technical Advantages

Under the ASTM A312 / ASME SA312 specification,TP304L stainless steel is a low-carbon version of Type 304 austenitic stainless steel. It is commonly dual-certified as EN 1.4307.

The defining feature of 304L stainless steel is its reduced carbon content (maximum 0.03%), compared with 0.08% in standard 304 stainless steel. This lower carbon level significantly reduces the risk of chromium carbide precipitation during welding, preventing intergranular corrosion in the heat-affected zone (HAZ).

Because of these characteristics, ASTM A312 TP304L seamless pipes are widely used in industries requiring extensive welding, high corrosion resistance, and long-term structural reliability.

Using304L stainless steel in seamless pipe form provides several important engineering advantages in demanding industrial environments.

Resistance to Intergranular Corrosion

Thelow carbon composition prevents the formation of chromium carbides at grain boundaries during exposure to temperatures between 425°C and 815°C, a phenomenon known as sensitization. This ensures the material maintains its corrosion resistance after welding.

Excellent Weldability

Because of its low carbon content, TP304L stainless steel often does not require post-weld heat treatment, reducing fabrication time and installation costs for large piping systems.

High Pressure Reliability

Theseamless pipe structure eliminates longitudinal weld seams, resulting in improved structural integrity and higher allowable working pressures in critical process systems.

Superior Formability and Fabrication Performance

TP304L stainless steel maintains excellent ductility and workability, allowing the pipe to be easily processed through bending, flanging, forming, and complex piping fabrication.

Excellent Low-Temperature Toughness

As an austenitic stainless steel, TP304L retains high impact toughness and mechanical stability at cryogenic temperatures, making it suitable for low-temperature applications.

To provide a comprehensive understanding of our Seamless Stainless steel 304L pipe, here are the detailed technical specifications and performance data.

The exceptional properties of 304L are a direct result of its specialized low-carbon chemical composition.

Despite its lower carbon content, 304L maintains excellent mechanical properties.

Here are some of the key physical properties of 304L that dictate its performance in various applications.

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

Typical Applications of ASTM A312 TP304L Seamless Pipe

Due to its corrosion resistance and excellent weldability, TP304L seamless stainless steel pipe is widely used in industries that require extensive welding and high structural reliability.

Product Specifications and Data

Chemical Composition

GradeCSiMnCrNiSP
304≤ 0.08≤1.00≤2.0018.00-20.008.00-11.00≤0.03≤0.045
304L≤0.035≤1.00≤2.0018.00-20.008.00-13.00≤0.03≤0.045
304H0.04-0.10≤1.00≤2.0018.00-20.008.00-11.00≤0.03≤0.045

Typical Mechanical Properties

MaterialTensile Strength ksi(MPa)Yield Strength ksi(MPa)Elongation (%)Hardness Brinell/VickersHardness Rockwell
304≥75(515)≥30(205)≥ 35≤192HBW/200HV≤90HRB
304L≥70(485)≥25(170)≥ 35≤192HBW/200HV≤90HRB
304H≥75(515)≥30(205)≥ 35≤192HBW/200HV≤90HRB

Typical Physical Properties

DensityMelting PointThermal ExpansionThermal ConductivityModulus of ElasticityElectrical Resistivity
8.0 g/cm³1400-1450 ℃17.2 µm/m·℃16.2 W/m·K193 GPa0.72 µΩ·m

Dimensional Standards and Tolerances

StandardOD(D)Tolerance （MM)Thickness(S)Tolerance(MM)LengthTolerance
MMCommonHighMMMM
ASTM A312D ≤48.3+0.4/-0.810.3 ≤73+20%-12.5%+6.0/0
48.3 ≤114.30±0.888.9 ≤457.2,t/D ≤5%+22.5%/-12.5%
114.3 ≤219.1+1.6/-0.888.9 ≤457.2,t/D >5%+15%/-12.5%
219.1 ≤457.2+2.4/-0.8D ≥508, t/D≤5%,SMLS+22.5%/-12.5%
457.2 ≤660.4+3.2/-0.8D ≥508, t/D>5%,SMLS+15%/-12.5%
660.4 ≤863.6+4.0/-0.8D ≥508, WELD+17.5%/-12.5%
863.6 ≤1219.2+4.8/-0.8
JIS 3459 Hot-Finished Smls PipeD ＜50±0.51S ＜4±0.5
D ≥50±1.0%S ≥4±12.5%
JIS 3459 Cold-FinishedD ＜30±0.3S ＜2±0.2
D ≥30±1.0%S ≥2±10.0%
JIS G3463 Hot-Finished Smls Pipe100+0.4/-0.8D ＜100， S/D+7/0
D ＜100， 2≤S+40%/0D+10/0
D ＜100， 2.4≤S+35%/0
D ＜100， 3.8≤S+33%/0
D ＜100， 4.6≤S+28%/0D+13/0
100 ≤D+0.4/-1.2D>100, S ＜2/
120 ≤DD>100 ， 2≤S/D+15/0
160 ≤D+0.4/-1.8D>100 ， 2.4≤S+35%/0
200 ≤D+0.4/-2.4D>100 ， 3.8≤S+33%/0D>50,7+10/0
D>100 ， 4.6≤S+28%/0
JIS G3463 Cold-finished+0.4/-0.8D+0.4/0
60 ≤D±0.3D ≥2.0+20%/0D>50,7+13/0
80 ≤D±0.4D ≥40+22%/0
100 ≤D+0.4/-0.6
120 ≤D+0.4/-0.8D>50,10M+15/0
160 ≤D+0.4/-1.2
200 ≤D+0.4/-1.6
GB/T 14975 冷拔(扎)钢管D±0.3±0.1所有壁厚，普通级PA+12.5%/-10%
12.7±0.15
38.1±0.4±0.3
88.9±0.9%±0.4
139.7±0.8所有壁厚，高级PC±10%
203.2±1.1
219.1±1.6
D ≥323.9±0.5%
GB/T 14976 冷拔(轧)钢管6±0.2±0.15S ≤3±12%(10% /0 高级PC)
10 ≤D±0.2±0.2
30 ≤D±0.2±0.3S>3+12.5%/-10%(10%/0 高级PC)
50 ≤D0.85%0.75%
D>2190.9%0.8%Smin, all+22%/0(+20%/0 高级PC)

Common Industrial Applications

Due to its corrosion resistance and excellent weldability, TP304L seamless stainless steel pipe is widely used in industries that require extensive welding and high structural reliability.

Petrochemical and Oil Refining

  • Process piping systems
  • Heat exchanger tubing
  • Corrosion-resistant pipelines
  • Field-welded piping installations

Nuclear and Power Generation

  • Cooling water systems
  • Structural containment components
  • Corrosion-resistant piping for high-reliability systems

Chemical Processing Industry

  • Nitric acid
  • Oxidizing chemicals
  • Industrial solvents
  • Corrosive process fluids

High-Purity Processing Industries

  • Food and beverage processing
  • Pharmaceutical manufacturing
  • Biotechnology production systems
  • CIP (Clean-in-Place) sanitary piping systems

Quality Assurance and Manufacturing Process

To ensure reliability and full traceability, all Seamless Stainless Steel TP304L Pipes are supplied with comprehensive testing and certification documentation in compliance with ASTM A312 / ASME SA312 standards.

Every TP304L seamless pipe undergoes strict quality control from billet selection through forming, heat treatment and final inspection:

Certification

  • EN 10204 3.1 / 3.2 Material Test Certificates (MTC) issued for every heat
  • Compliance with ASTM A312 / ASME SA312 and ASTM A213 / ASME SA213
  • Full heat traceability from raw material to finished pipe

Non-Destructive Testing (NDT)

  • Ultrasonic Testing (UT) per ASTM E213
  • Eddy Current Testing (ET) for surface and near-surface defects
  • Hydrostatic pressure testing to verify pipe integrity

Material Verification

  • 100% Positive Material Identification (PMI)
  • Chemical analysis confirming composition against the specified grade
  • Carbon and sulfur analysis where required

Mechanical Testing

  • Tensile, yield and elongation testing per ASTM A370
  • Hardness testing to confirm the specified condition
  • Flattening, flaring and intergranular corrosion tests

Dimensional Inspection

  • OD, wall thickness and ovality verified against the tolerance table
  • Length, straightness and end preparation checked before dispatch
  • Third-party inspection available through ABS, DNV, BV, TUV or SGS

TP304L vs TP304 / TP304H – Technical Comparison

TP304L (UNS S30403) is the extra-low-carbon version of Type 304 stainless steel. Along with TP304 and TP304H it forms the most widely used family of austenitic stainless steel pipe grades, differentiated by carbon content and intended service temperature.

Chemical and Metallurgical Differences

  • Carbon content: TP304 allows 0.080% max, TP304L limits carbon to 0.030% max, and TP304H requires 0.040–0.100%.
  • Chromium and nickel: TP304 and TP304L specify 18.00–20.00% Cr and 8.00–12.00% Ni; TP304H is held to 8.00–11.00% Ni.
  • Silicon and manganese: All grades limit Si to 1.00% and Mn to 2.00% max.
  • Microstructure: The low carbon of TP304L prevents chromium carbide precipitation at grain boundaries, preserving corrosion resistance after welding.

Mechanical Properties Comparison

  • Tensile strength: TP304L requires 485 MPa (70 ksi) minimum; TP304H requires 515 MPa (75 ksi) minimum.
  • Yield strength: TP304L requires 170 MPa (25 ksi) minimum; TP304H requires 205 MPa (30 ksi) minimum.
  • Elevated temperature: TP304H is preferred above 525°C because its higher carbon content improves creep and rupture strength.
  • Low-temperature toughness: TP304L retains good impact toughness down to cryogenic temperatures.

Corrosion and Welding Behaviour

  • Intergranular corrosion: TP304L is immune to sensitization after welding without post-weld heat treatment, unlike standard TP304.
  • Weldability: TP304L is the standard choice for field-welded and heavily fabricated piping systems.
  • General corrosion: All grades provide equivalent resistance to atmospheric, fresh water and oxidizing chemical media.
  • Cost position: TP304, TP304L and TP304H are normally priced within a narrow band, so grade selection follows the welding and temperature requirement.

Selection Guide

  • ChooseTP304L for welded piping systems, chemical process lines, food and pharmaceutical service and cryogenic applications.
  • ChooseTP304 for general corrosion-resistant service where welding is limited.
  • ChooseTP304H for elevated-temperature service above 525°C such as superheater and heat-exchanger tubing.

Frequently Asked Questions

What is TP304L seamless pipe?

TP304L (UNS S30403) is an extra-low-carbon austenitic stainless steel seamless pipe containing 18.00–20.00% Cr and 8.00–12.00% Ni, with carbon limited to 0.030% maximum. The low carbon content makes it resistant to intergranular corrosion after welding.

What is the difference between TP304 and TP304L?

The difference is carbon content. TP304 permits up to 0.080% carbon while TP304L allows only 0.030%. This makes TP304L immune to sensitization in the 425–815°C range, so it does not require post-weld heat treatment in corrosive service.

Is TP304L suitable for cryogenic service?

Yes. As an austenitic stainless steel, TP304L retains high impact toughness at cryogenic temperatures and is commonly used in LNG, liquid nitrogen and other low-temperature systems, subject to the applicable design code requirements.

What is TP304L pipe used for?

Typical uses include petrochemical and oil refining process piping, heat-exchanger tubing, nuclear and power generation cooling systems, chemical processing, food and beverage production, pharmaceutical manufacturing and sanitary CIP piping.

Ready to Request a Quotation?

Send your Seamless Stainless steel TP304L pipe enquiry with grade, applicable ASTM/ASME standard and edition, OD × wall thickness, length, quantity, end finish, delivery destination and inspection documents — you will get a written quotation stating the specification and edition, delivery condition, documents included and lead time.

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