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TP304L vs TP316L: Composition & Key Differences

Aug 07, 2025

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Contents
  1. What is TP304L?
  2. What is TP316L material?
  3. Equivalent Materials of TP304L and TP316L
  4. Chemical Composition of TP304L and TP316L (wt%, ASTM A312)
  5. Mechanical Properties of TP304L and TP316L (Solution‑Annealed, Room Temp, ASTM A312 Minimum)
  6. Physical Properties of TP304L and TP316L
  7. Key Performance Differences of TP304L and TP316L
  8. Typical Applications
  9. Exporter of TP304L and TP316L
  10. Quick Selection Guide
  11. FAQ

What is TP304L?

ASTM A312 TP304L is a low-carbon austenitic grade designed with a superior composition of nickel and chromium, giving enhanced resistance against corrosive and oxidative media. These pipes have enhanced strength and can work in high-temperature setups

 

What is TP316L material?

A312 TP316L is the low-carbon austenitic grade produced with nickel, chromium and molybdenum (2.0–3.0%). The molybdenum addition provides superior corrosion and oxidation resistance, particularly against chlorides, pitting and crevice corrosion - making 316L the standard for marine, coastal and chemical service.

 

Both TP304L (UNS S30403) and TP316L (UNS S31603) are low‑carbon austenitic stainless‑steel pipe grades covered under ASTM A312. The letter "L" stands for low carbon (max 0.03%), minimizing carbide precipitation and intergranular corrosion after welding

 

Equivalent Materials of TP304L and TP316L

ASTM A312 Grade
EN (Europe)
DIN (Germany)
JIS (Japan)
GB (China)
TP304L
EN 1.4307 / X2CrNi18-9
1.4307
SUS304L
022Cr19Ni10
TP316L
EN 1.4404 / X2CrNiMo17-12-2
1.4404
SUS316L
022Cr17Ni12Mo2
 
 
 

Chemical Composition of TP304L and TP316L (wt%, ASTM A312)

Element TP304L (S30403) TP316L (S31603)
Carbon (C) ≤0.03 ≤0.03
Chromium (Cr) 18.0‑20.0 16.0‑18.0
Nickel (Ni) 8.0‑13.0 10.0‑14.0
Molybdenum (Mo) ‑ 2.0‑3.0
Manganese (Mn) ≤2.00 ≤2.00
Silicon (Si) ≤1.00 ≤1.00
P / S ≤0.045 / ≤0.030 ≤0.045 / ≤0.030
Iron Balance Balance

Key alloy difference: TP316L contains 2.0‑3.0% molybdenum, which TP304L does not have. Molybdenum greatly improves resistance to chloride‑induced pitting and crevice corrosion. PREN value: TP304L ≈18‑20; TP316L ≈24.

 

Mechanical Properties of TP304L and TP316L (Solution‑Annealed, Room Temp, ASTM A312 Minimum)

Property TP304L TP316L
Tensile Strength (MPa) ≥ 485 ≥ 485
Yield Strength (0.2%, MPa) ≥ 170 ≥ 170
Elongation (%) ≥ 35 ≥ 35
Hardness (HRB) ≤ 90 ≤ 90

Note: Room‑temperature mechanical properties are close for both grades. The major gap lies in corrosion performance rather than strength.

 

Physical Properties of TP304L and TP316L

Property TP304L TP316L
Density (g/cm³) 8.00 7.99
Melting Point (°C) 1400–1450 1370–1400
Thermal Conductivity (W/m·K) 16.2 (at 100 °C) 16.3 (at 100 °C)
Specific Heat (J/kg·K) 500 500
Electrical Resistivity (μΩ·cm) 72 74

 

Key Performance Differences of TP304L and TP316L

1.Chloride corrosion resistance

TP304L works well for fresh water, atmospheric and mild corrosive environments; poor performance under high‑chloride conditions. TP316L with molybdenum delivers excellent pitting & crevice corrosion resistance for chloride‑rich media, coastal and marine environments.

2.Weldability

Both are low‑carbon grades. No post‑weld solution annealing is normally required; weld sensitization risk is greatly reduced. Recommended filler: ER308L for TP304L, ER316L for TP316L.

3.Cost

TP316L has higher nickel plus molybdenum content, so raw‑material cost is higher than TP304L.

 

Typical Applications

1.TP304L
General process piping, purified‑water systems, food & beverage pipelines, pharmaceutical piping, indoor low‑chloride industrial equipment.
2.TP316L
Chemical processing, coastal/marine piping, heat exchangers, salt‑containing media, desalination, pulp‑and‑paper equipment, demanding pharmaceutical production lines
Stainless steel piping for purified water

Stainless steel piping for purified water

Stainless steel piping for the pharmaceutical industry

Stainless steel piping for the pharmaceutical industry

Process piping

Process piping

 

Exporter of TP304L and TP316L

As a trusted supplier of duplex stainless steel, GNEE offers comprehensive support to customers worldwide. GNEE not only stocks a wide range of stainless steel grades, including TP304, TP304L, and TP316, but also offers custom fabrication services, including plate cutting, edge processing, and surface treatment. GNEE also boasts efficient export logistics capabilities, enabling delivery to the Middle East, Southeast Asia, Europe, and other regions. GNEE also provides professional documentation support, including EN 10204 3.1 MTC and third-party inspection reports, to fully meet our customers' diverse needs.
Contact us today to receive a preferential quote or technical data sheet for ASTM A312 stainless steel pipe.Email: sales@gneestainless.com

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Quick Selection Guide

Choose TP304L: Mild corrosion, fresh water, no high chloride requirement, cost‑sensitive projects.
Choose TP316L: Chloride‑containing media, coastal/marine atmosphere, chemical process with pitting risk.
 

FAQ

1.Can TP304L replace TP316L?

Not for chloride‑rich conditions. Without molybdenum, TP304L is prone to pitting corrosion in salt‑containing service.

 

2.Why "L" grade for ASTM A312 pipe?

Low carbon limits chromium‑carbide precipitation in weld heat‑affected zones, preserving corrosion resistance without post‑weld heat treatment.

 

3.Are mechanical strengths much different?

No. Their minimum tensile and yield values are similar; corrosion performance is the main distinction.

 

 

 

 

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