Product Description
A213 Tp304/304L/316/316L SMLS Stainless Steel Tubes
1. Introduction
The A213 standard by ASTM International is designed for seamless ferritic and austenitic alloy - steel boiler, superheater, and heat - exchanger tubes. Tp304, Tp304L, Tp316, and Tp316L are austenitic stainless - steel grades within this standard. Seamless (SMLS - Seamless Mechanical Longitudinal Welded Steel) construction ensures high integrity and reliability, making these tubes suitable for a wide range of high - temperature and high - pressure applications.
2. Chemical Composition
2.1 Tp304
- Chromium (Cr): 18.0 - 20.0%. Chromium is a key element that forms a passive oxide layer on the surface of the steel, providing excellent corrosion resistance. It also contributes to the high - temperature strength of the alloy.
- Nickel (Ni): 8.0 - 10.5%. Nickel stabilizes the austenitic structure of the steel, enhancing its toughness, formability, and corrosion resistance, especially in reducing environments.
- Carbon (C): ≤0.08%. Carbon content affects the strength and weldability of the steel. In Tp304, the relatively low carbon content helps maintain good weldability without sacrificing too much strength.
- Manganese (Mn): ≤2.00%. Manganese is added as a deoxidizer and to improve the strength and hardenability of the steel.
- Silicon (Si): ≤1.00%. Silicon also acts as a deoxidizer and can enhance the strength and oxidation resistance of the steel at elevated temperatures.
2.2 Tp304L
- Chromium (Cr): 18.0 - 20.0%, similar to Tp304.
- Nickel (Ni): 8.0 - 12.0%. The nickel range is slightly broader compared to Tp304.
- Carbon (C): ≤0.03%. The significantly lower carbon content in Tp304L is the main differentiator from Tp304. This low carbon level minimizes the risk of carbide precipitation during welding, improving the intergranular corrosion resistance, especially in welded structures.
- Manganese (Mn): ≤2.00%, and Silicon (Si) ≤1.00%, with functions similar to those in Tp304.
2.3 Tp316
- Chromium (Cr): 16.0 - 18.0%. The chromium content is slightly lower than that of Tp304, but the overall corrosion resistance is still high due to other alloying elements.
- Nickel (Ni): 10.0 - 14.0%. Nickel stabilizes the austenitic structure and contributes to corrosion resistance.
- Molybdenum (Mo): 2.0 - 3.0%. Molybdenum is a crucial addition in Tp316. It significantly improves the pitting and crevice corrosion resistance, especially in chloride - containing environments.
- Carbon (C): ≤0.08%. Similar to Tp304, carbon content affects strength and weldability.
- Manganese (Mn): ≤2.00% and Silicon (Si) ≤1.00%, with their usual roles.
2.4 Tp316L
- Chromium (Cr): 16.0 - 18.0%, like Tp316.
- Nickel (Ni): 10.0 - 14.0%, same as Tp316.
- Molybdenum (Mo): 2.0 - 3.0%, providing excellent pitting and crevice corrosion resistance.
- Carbon (C): ≤0.03%. The low - carbon version of Tp316, Tp316L, has enhanced intergranular corrosion resistance, especially important for welded components in corrosive environments.
3. Mechanical Properties
3.1 Tp304
- Tensile Strength: ≥515 MPa. This relatively high tensile strength allows Tp304 tubes to withstand significant pulling forces in applications such as heat - exchanger tubes in power plants.
- Yield Strength: ≥205 MPa. Tp304 can resist plastic deformation under normal operating stress, ensuring the integrity of the tubes.
- Elongation: ≥40%. Good elongation indicates high ductility, enabling the tubes to be easily formed into various shapes during manufacturing processes like bending and flanging.
3.2 Tp304L
- Tensile Strength: ≥485 MPa. Slightly lower than Tp304 due to its lower carbon content.
- Yield Strength: ≥170 MPa. Also lower than Tp304, but still sufficient for many applications. The lower strength is a trade - off for improved corrosion resistance in welded joints.
- Elongation: ≥40%, similar to Tp304, maintaining good formability.
3.3 Tp316
- Tensile Strength: ≥515 MPa, comparable to Tp304.
- Yield Strength: ≥205 MPa, similar to Tp304. The addition of molybdenum does not significantly reduce the strength but enhances corrosion resistance.
- Elongation: ≥40%, ensuring good formability for manufacturing purposes.
3.4 Tp316L
- Tensile Strength: ≥485 MPa, lower than Tp316 due to the reduced carbon content.
- Yield Strength: ≥170 MPa, also lower. However, the focus is on its excellent corrosion resistance, especially in welded conditions.
- Elongation: ≥40%, maintaining good ductility for shaping operations.
4. Corrosion Resistance
4.1 Tp304
- General Corrosion Resistance: Tp304 offers good general corrosion resistance in a variety of environments, including atmospheric, fresh - water, and many chemical - free industrial environments. The chromium - rich passive film formed on its surface protects the underlying metal from corrosion.
- Limitations: However, it is less resistant to chloride - containing environments compared to Tp316 and Tp316L. Chloride ions can penetrate the passive film, leading to pitting and crevice corrosion, especially at higher temperatures.
4.2 Tp304L
- Intergranular Corrosion Resistance: Tp304L has significantly better intergranular corrosion resistance than Tp304, especially in welded components. The low - carbon content reduces the formation of chromium - carbide precipitates at grain boundaries during welding, which can cause intergranular corrosion in Tp304.
- General Corrosion: Its general corrosion resistance is similar to Tp304 in non - chloride - containing environments.
4.3 Tp316
- Pitting and Crevice Corrosion Resistance: Tp316 is highly resistant to pitting and crevice corrosion, mainly due to the addition of molybdenum. This makes it suitable for applications in chloride - rich environments, such as marine and chemical processing industries.
- General Corrosion: It also has good general corrosion resistance, similar to Tp304, but with enhanced performance in more aggressive environments.
4.4 Tp316L
- Combined Corrosion Resistance: Tp316L combines the excellent pitting and crevice corrosion resistance of Tp316 with the enhanced intergranular corrosion resistance due to its low - carbon content. This makes it an ideal choice for applications where welded components are exposed to harsh, chloride - containing, and corrosive environments.
5. Machinability
5.1 Tp304
- Fair Machinability: Tp304 has fair machinability. The austenitic structure and the presence of alloying elements can make machining challenging. During machining, issues such as work - hardening can occur. Proper tool selection, such as using carbide - tipped tools, and appropriate cutting parameters, including a relatively lower cutting speed compared to some carbon steels, are necessary to achieve good surface finish and efficient machining.
5.2 Tp304L
- Similar Machinability to Tp304: Tp304L has similar machinability to Tp304. The low - carbon content does not significantly affect the machining process, and the same machining techniques and tooling are generally applicable.
5.3 Tp316
- Slightly More Difficult Machining: Tp316 can be slightly more difficult to machine than Tp304 due to the addition of molybdenum. Molybdenum increases the alloy's hardness, which may require more robust tooling and adjusted cutting parameters. Carbide - based tools are often preferred, and cutting speeds may need to be further reduced to prevent excessive tool wear.
5.4 Tp316L
- Machinability Similar to Tp316: Tp316L has machinability similar to Tp316. The low - carbon content does not have a major impact on the machining characteristics, and the challenges related to the presence of molybdenum are the same as in Tp316.
6. Applications
6.1 Tp304
- Heat Exchangers: Commonly used in heat - exchanger applications in power plants, HVAC systems, and industrial processes where general corrosion resistance and good heat - transfer properties are required.
- Food and Beverage Industry: Suitable for equipment in the food and beverage industry as it meets the hygiene requirements and has good corrosion resistance to many food - related substances.
6.2 Tp304L
- Welded Structures in Corrosive Environments: Tp304L is preferred for welded components in environments where intergranular corrosion could be a problem, such as in some chemical processing plants and pharmaceutical manufacturing facilities.
- Architecture and Construction: Used in architectural applications, such as handrails and decorative elements, where corrosion resistance and formability are important.
6.3 Tp316
- Marine Applications: Tp316 is widely used in marine environments, including shipboard heat exchangers, seawater piping systems, and marine equipment, due to its excellent resistance to chloride - induced corrosion.
- Chemical Processing: Ideal for chemical processing plants where it can withstand the corrosive effects of various chemicals, especially those containing chlorides.
6.4 Tp316L
- High - Purity and Corrosive Applications: Tp316L is used in applications where high - purity materials are required, such as in the pharmaceutical and biotechnology industries, as well as in extremely corrosive environments where both pitting and intergranular corrosion resistance are crucial.
- Offshore Oil and Gas: In offshore oil and gas platforms, Tp316L tubes are used in pipelines and equipment due to their ability to resist the harsh marine and chemical environments.
7. ASTM A312 TP 304 Chemical Composition
Manufacturer of SA312 TP304 Pipe in Schedule 10, 40 and other wall thickness, PED approved ASTM A312 TP 304 Seamless pipe suppliers, check dimensions and thickness chart
| Grade |
Carbon |
Sulfur |
Manganese |
Chromium |
Phosphorus |
Silicon |
Nickel |
| TP304 |
0.08 |
0.03 |
2 |
18.0-20.0 |
0.045 |
1 |
8.0-11.0 |
Mechanical Properties of SA 312 TP 304 ERW Pipes
| Material |
Yield Strength |
Heat |
Tensile Strength |
Temperure |
Elongation |
| Ksi (MPa), Min. |
Treatment |
Ksi (MPa), Min. |
Min.º F(º C) |
| TP304 |
30(205) |
Solution |
75(515) |
1900 (1040) |
35 |
Equivalent of ASTM A312 TP304 Seamless Pipe
| Werkstoff/ DIN |
European Standards grades |
ASTM grades |
| 1.4301 |
X5CrNi18-10 |
A 312 Grade TP304 |
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