304 Stainless Steel Pipe – Material & Specification Guide

304 Stainless Steel Pipe (UNS S30400), with its 18/8 chromium-nickel composition (18% Cr / 8% Ni), is the most widely used austenitic stainless steel, offering an optimal balance of corrosion resistance, strength, and cost-effectiveness. It is available in seamless, welded, and EFW forms, meeting ASTM A312 and ASME SA312 standards. This guide provides complete material and specification information to support your procurement and engineering decisions.

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What is Stainless Steel Pipe?

Stainless steel pipe is a long round steel material that is hollow and extends longitudinally. Stainless steel pipe is widely used in petroleum, chemical, medical, food, light industry, equipment and instruments, structural parts, etc. In addition, when the torsional strength and anti-torsion strength are equal, stainless steel is lighter, so it is often used in mechanical equipment parts and engineering structural parts, and is also commonly used as furniture and kitchen utensils, etc. Stainless steel pipes can be divided into seamless stainless steel pipes and welded stainless steel pipes according to the production process.

Stainless steel pipes have excellent corrosion resistance due to the addition of Ni and Cr chemical elements to adapt to different environments. Commonly used materials are 304/L and 316/L, and the standards are ASTM A312, A213, A270, etc. It is safe, reliable, hygienic, environmentally friendly, economical and applicable, and can resist corrosion from weak corrosive media such as air, steam, and water, and chemically corrosive media such as acids, alkalis, and salts.

What is 304 Stainless Steel Pipe?

304 stainless steel pipe is a common stainless steel pipe with excellent corrosion resistance and a beautiful surface. It is widely used in construction, decoration, machinery, and other fields.

Key properties of 304 stainless steel pipe:
● Corrosion Resistance: Excellent resistance to a wide range of corrosive environments, including many acids and alkalis.
● Heat Resistance: Can operate continuously at temperatures up to approximately 870°C, with short-term service up to 1000-1200°C.
● Strength: Minimum yield strength of 205MPa and minimum tensile strength of 515MPa.
● Formability: Excellent formability and weldability, making it suitable for various fabrication methods.

ASTM A312 TP304 pipe is used for high-pressure and high-temperature applications. ASME SA312 Grade 304 welded pipes are among the most cost-effective and widely used stainless steel pipes in the world.

304 Stainless Steel Material

304 stainless steel is a grade produced in accordance with American ASTM standards (ASTM A312). It is a general-purpose stainless steel material with stronger anti-rust performance than 200 series stainless steel materials.

304 stainless steel has excellent corrosion resistance and good intergranular corrosion resistance. For oxidizing acids, experiments have shown that 304 stainless steel has strong corrosion resistance in nitric acid with a concentration of ≤65% below boiling temperature. It also has good corrosion resistance to alkali solutions and most organic and inorganic acids.

▶ For a basic introduction to 304 seamless stainless steel pipe, please refer to our [304 Seamless Stainless Steel Pipe Guide].

304 Stainless Steel Pipe Specifications

Specification	Details
Standards	ASTM A312 / ASME SA312 (Seamless & Welded), ASTM A358 / ASME SA358 (EFW)
Dimensions	ASTM, ASME and API
SS 304 Seamless Pipe Size	1/8″ NB – 16″ NB
SS 304 ERW Pipe Size	1/8″ NB – 24″ NB
SS 304 EFW Pipe Size	6″ NB – 100″ NB
Schedule	SCH 20, SCH 30, SCH 40, STD, XS, SCH 60, SCH 80, SCH 120, SCH 140, SCH 160, XXS
Type	Seamless / ERW / Welded / Fabricated / LSAW Pipes
Form	Round, Square, Rectangular, Hydraulic, etc.
Length	Single Random, Double Random & Cut Length
End Finish	Plain End, Beveled End, Threaded

Schedule Chart of ASTM A312 TP304/304L SS Welded Pipe

Pipe Size	Outside Diameter	Available Schedules
1/8" IPS	.405" O.D.	SCH 40, 80
1/4" IPS	.540" O.D.	SCH 10, 40, 80
3/8" IPS	.675" O.D.	SCH 10, 40, 80
1/2" IPS	.840" O.D.	SCH 5, 10, 40, 80, 160, XXH
3/4" IPS	1.050" O.D.	SCH 10, 40, 80, 160, XXH
1" IPS	1.315" O.D.	SCH 5, 10, 40, 80, 160, XXH
1-1/4" IPS	1.660" O.D.	SCH 10, 40, 80, 160, XXH
1-1/2" IPS	1.900" O.D.	SCH 10, 40, 80, 160, XXH
2" IPS	2.375" O.D.	SCH 10, 40, 80, 160, XXH
2-1/2" IPS	2.875" O.D.	SCH 10, 40, 80, 160, XXH
3" IPS	3.500" O.D.	SCH 5, 10, 40, 80, 160, XXH
3-1/2" IPS	4.000" O.D.	SCH 10, 40, 80, 160, XXH
4" IPS	4.500" O.D.	SCH 10, 40, 80, 160, XXH
5" IPS	5.563" O.D.	SCH 10, 40, 80, 160, XXH
6" IPS	6.625" O.D.	SCH 5, 10, 40, 80, 120, 160, XXH
8" IPS	8.625" O.D.	SCH 5, 10, 40, 80, 120, 160, XXH
10" IPS	10.750" O.D.	SCH 10, 20, 40, 80
12" IPS	12.750" O.D.	SCH 10, 20, 40, 80
14" IPS	14.000" O.D.	SCH 10, 40
16" IPS	16.000" O.D.	SCH 10, 40
18" IPS	18.000" O.D.	SCH 40

Chemical Composition of 304 Stainless Steel

The chemical composition of 304 stainless steel mainly includes carbon (C), silicon (Si), manganese (Mn), chromium (Cr), nickel (Ni), sulfur (S), phosphorus (P) and nitrogen (N). The contents of chromium and nickel have a decisive influence on performance. 304 contains 18% chromium and 8% nickel. It is equivalent to China's 0Cr19Ni9 (0Cr18Ni9) stainless steel.

Element	Content (%)
Carbon (C)	≤0.08
Silicon (Si)	≤1.0
Manganese (Mn)	≤2.0
Chromium (Cr)	18.0 – 20.0
Nickel (Ni)	8.0 – 10.5
Sulfur (S)	≤0.03
Phosphorus (P)	≤0.045
Nitrogen (N)	≤0.1

Mechanical Properties of 304 Stainless Steel Pipe

Property	Value
Tensile Strength	≥515 MPa
Yield Strength (min)	≥205 MPa
Elongation	≥35% (typically)
Hardness (Brinell)	≤201 HB
Max. Service Temperature (Continuous)	~870°C

304 vs 304L Stainless Steel: How to Choose?

Both 304 and 304L are austenitic stainless steels. The most basic difference is carbon content. "L" stands for low carbon: 304L has ≤0.03% C, while 304 has ≤0.08% C.

The key advantage of 304L is its resistance to intergranular corrosion after welding. The lower carbon content reduces the precipitation of chromium carbides in the welded area, which can cause sensitization and reduce corrosion resistance.

Feature	Grade 304	Grade 304L
Carbon Content	≤0.08%	≤0.03%
Corrosion Resistance (General)	Excellent	Excellent
Corrosion Resistance (After Welding)	Good	Superior
Cost	Lower	Higher
Best For	General purpose, non-welded or thin-walled applications	Welded structures, thick sections, and applications without post-weld heat treatment

Selection Advice: For most standard piping applications, 304 offers the best value. For welded components without post-weld heat treatment, especially those with wall thickness over 1/4 inch, 304L is the safer, more reliable choice to prevent weld decay.

Production Process of 304 Seamless Stainless Steel Pipe:

304 seamless stainless steel pipes are made from steel ingots or solid tube blanks that are perforated into capillary tubes, and then hot rolled, cold rolled or cold drawn. The production process mainly includes smelting, rolling, piercing, straightening, cutting and other links. Each link has specific requirements and operating specifications to ensure high-quality products.

Application fields of 304 stainless steel pipes

304 stainless steel pipes are widely used in the following fields:
1. Chemical industry: 304 stainless steel pipes are widely used in the chemical industry, such as manufacturing various chemical equipment, pipelines, valves, etc. Its excellent corrosion resistance can withstand the erosion of various corrosive media such as acids and alkalis.
2. Construction field: In the construction field, 304 stainless steel pipes are mainly used for decoration, railings, handrails, etc. Its beautiful appearance and excellent mechanical properties make it an ideal material for architectural decoration.
3. Mechanical equipment: 304 stainless steel pipes also occupy an important position in the field of mechanical equipment manufacturing. Such as manufacturing bearings, transmission parts, hydraulic systems, etc., its excellent mechanical properties and corrosion resistance can meet the needs of various complex working conditions.
4. Food processing: In the field of food processing, 304 stainless steel pipes are favored because of their non-toxic, odorless and easy to clean characteristics. It is widely used in the manufacture of various food processing equipment, pipelines, etc.
5. Other fields: In addition, 304 stainless steel pipes have also been widely used in environmental protection, medical equipment, shipbuilding and other fields.

Frequently Asked Questions:

Q1: What is the difference between 304 and 304L stainless steel pipe?
A: The key difference is carbon content. 304L has a lower carbon content (≤0.03%) than 304 (≤0.08%), which gives 304L better resistance to intergranular corrosion after welding. For most general applications, 304 is sufficient. For welded structures without post-weld heat treatment, 304L is recommended.

Q2: What sizes are available for 304 stainless steel pipe?
A: We supply 304 stainless steel pipe in seamless sizes from 1/8″ NB to 16″ NB, ERW sizes from 1/8″ NB to 24″ NB, and EFW sizes from 6″ NB to 100″ NB. Custom sizes are available upon request.

Q3: What schedules are available for 304 stainless steel pipe?
A: We offer SCH 20, SCH 30, SCH 40, STD, XS, SCH 60, SCH 80, SCH 120, SCH 140, SCH 160, and XXS.

Q4: Do you provide material test certificates?
A: Yes, we provide complete material test certificates (MTC) with full traceability, including chemical composition and mechanical property reports for all our 304 stainless steel pipes.

Q5: What is the maximum working temperature for 304 stainless steel pipe?
A: 304 stainless steel pipe can be used continuously at temperatures up to approximately 870°C. For short-term service, it can withstand temperatures up to 1000-1200°C.

Q6: What is the minimum order quantity (MOQ)?
A: Please contact our sales team for MOQ details, as it varies by size and specification.

Advantages and precautions of 304 stainless steel pipes:

304 stainless steel pipes have the advantages of corrosion resistance, beauty, hygiene and environmental protection, high strength, safety and reliability, etc., and can withstand corrosion from weak corrosive media such as air, steam, and water, and chemically corrosive media such as acids, alkalis, and salts. However, the following points should also be noted during use:

1. During installation, care should be taken to protect the surface of the pipe to avoid scratches or bumps.
2. When welding, the correct welding process should be followed to ensure the quality of welding.
3. Avoid heavy pressure and impact during transportation and storage to avoid deformation or damage.
4. Regular inspection and maintenance are required during use to ensure the normal use and safety and reliability of the pipe.

In short, as a common metal material, 304 stainless steel pipes have a wide range of applications and excellent performance characteristics. During use, attention should be paid to maintenance and care to ensure its safe and reliable performance.

Read more: 304 vs. 316 Stainless Steel: Which is Better? or Stainless Steel Seamless Pipe Manufacturing Process