Type 304 Pipe

304 stainless steel pipe is a commonly used material for transporting fluids and gases. As an austenitic stainless steel containing 18% chromium and 8% nickel, its microstructure gives it excellent oxidation and corrosion resistance. This grade is favored for its high strength, good hygiene properties, and reliable operation under a wide range of temperature conditions, from low to high.

Its non-magnetic nature and excellent weldability make it ideal for complex piping systems assembled using common welding techniques. The smooth inner surface prevents product buildup and simplifies cleaning, making 304 pipe the standard choice for sanitary applications. Compared to carbon steel pipe, 304 pipe has a longer service life in corrosive environments, making it the preferred metal for projects with extremely high requirements for reliability and low maintenance costs.

⚠️ Reference Data Only: Values shown are typical industry standards and may vary by manufacturer, lot, and heat treatment. For critical applications, please contact us to verify specifications or request a Mill Test Report (MTR).

1. Mechanical Properties

2. Chemical Composition

3. Dimensions & Weight Schedule

Standard dimensions per ASTM A312 / ASME B36.19:

Schedule 5, 10, and XXS also available. Custom lengths up to 12 meters (40 ft).

4. Pressure Ratings (Typical, per ASME B31.3)

5. Temperature Range

6. Seamless vs. Welded 304 Pipe

We supply both seamless and welded 304 pipe. Contact us for the best option for your application.

Applicable Standards

ASTM A312: Standard Specification for Seamless, Welded, and Heavily Cold Worked Austenitic Stainless Steel Pipes

ASME B36.19: Stainless Steel Pipe Dimensions

ASTM A269: Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubing

Food & Beverage:

Sanitary piping, dairy tubing, and brewery transfer lines - Excellent cleanability and resistance to organic acids.

Chemical Processing:

Process piping and transfer lines for corrosive fluids - Resists a wide range of chemicals.

Pharmaceutical:

High-purity water systems and product transfer lines - Hygienic surface and proven corrosion resistance.

Water Treatment:

Distribution piping and filtration systems - Long service life in various water chemistries.

Architectural:

Handrails, decorative structures, and support posts - Aesthetic appeal and low maintenance.

Oil & Gas:

Instrumentation lines and low-pressure fluid transport - Good general corrosion resistance in non-chloride environments.

Cryogenics:

Liquefied gas transport lines - Retains toughness and strength at very low temperatures.

Automotive:

Exhaust system components and fluid lines - Resists high temperatures and corrosive condensates.

Machining

Type 304 stainless steel is tougher than carbon steel and prone to work-hardening, so sharp tooling, heavy positive feeds, and slow cutting speeds are critical. Take a continuous cut to stay below the work-hardened layer. Coolant and lubricant are essential — without them, the material will work-harden and destroy your tooling.

Welding

This grade offers excellent weldability and accepts all common fusion methods, including TIG (GTAW) and MIG (GMAW). Use 308L filler metal to prevent weld decay and maintain maximum corrosion resistance at the joint. Post-weld annealing is generally not required.

Finishing

304 pipe ships with a standard mill finish by default. For architectural or sanitary applications, it can be mechanically polished to a brushed, satin, or mirror finish. Chemical passivation is also an option to further enhance its natural corrosion resistance.

Available Surface Finishes

Installation & Maintenance Tips

Cutting: Use a band saw with bi-metal blades or an abrasive cutoff wheel. Apply cutting fluid to prevent work-hardening. Deburr all cut ends thoroughly.

Threading: Use sharp, stainless-rated dies with liberal threading oil. Chase to NPT standard taper (3/4" per foot).

Storage: Store on wooden racks or rubber pads away from carbon steel to prevent surface contamination. Keep end caps on until installation.

Cleaning: Use mild detergent and warm water. Never use steel wool or carbon steel brushes — embedded particles will rust. Passivate after welding or grinding to restore corrosion resistance.

Q: What is the difference between 304 and 304L stainless steel pipe?

A: 304L has a lower carbon content (0.03% max vs. 0.08% for 304) to minimize carbide precipitation during welding, which improves corrosion resistance at the weld seam. For most pipe applications, the material is dual-certified as 304/304L and is interchangeable.

Q: Is 304 pipe suitable for drinking water?

A: Yes, 304 stainless steel is widely used for potable water systems. It is lead-free, and its excellent corrosion resistance prevents the leaching of harmful materials, ensuring water purity and meeting public health standards.

Q: When should I use 316 pipe instead of 304?

A: Use 316 pipe for applications with significant exposure to chlorides, such as in marine environments, coastal areas, or for transporting certain industrial chemicals. The added molybdenum in 316 provides superior resistance to pitting and crevice corrosion caused by chlorides.

Q: What is the difference between Schedule 40 and Schedule 80 pipe?

A: Schedule 80 has a thicker wall than Schedule 40 for the same NPS size. For example, 2" Schedule 40 has a 0.154" wall while Schedule 80 has a 0.218" wall. Schedule 80 offers higher pressure ratings but weighs more and costs more. Schedule 40 is suitable for most general-purpose applications.

Q: Is 304 stainless steel pipe magnetic?

A: 304 stainless steel is generally non-magnetic in the annealed condition. Some slight magnetism can appear after cold working (bending, forming) due to the formation of martensite. This is normal and does not affect corrosion resistance.

Q: What welding filler metal should I use for 304 pipe?

A: Use ER308L or E308L filler metal. The "L" grade filler ensures the weld deposit has low carbon content, which prevents sensitization and maintains corrosion resistance at the weld joint.

Q: Can 304 pipe be bent and formed?

A: Yes. 304 pipe can be bent using standard shop equipment. It work-hardens more quickly than carbon steel, so mandrel bending is recommended for tight radii. Annealing may be required after severe cold forming to restore full corrosion resistance.

Q: What is the difference between 304 and 201 stainless steel?

A: 201 stainless steel replaces some nickel with manganese, making it less expensive but also less corrosion-resistant than 304. For outdoor, chemical, or sanitary applications, 304 is the preferred grade. 201 is sometimes used in indoor decorative applications where cost is the primary concern.